Fluke Lawn Mower 2635A User Manual

®
2635A  
Hydra Series II Data Bucket  
Users Manual  
PN 686698  
November 1997  
© 1997 Fluke Corporation, All rights reserved. Printed in U.S.A.  
All product names are trademarks of their respective companies.  
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Table of Contents  
Chapter  
1
Title  
Page  
Preparation for Use............................................................................ 1-1  
Introduction ....................................................................................................... 1-5  
Operating Modes ............................................................................................... 1-5  
Front Panel Operation................................................................................... 1-7  
Memory Card Operation ............................................................................... 1-7  
Computer Operation...................................................................................... 1-8  
Printer Operation........................................................................................... 1-8  
Modem Operation ......................................................................................... 1-8  
Measurement Capabilities................................................................................. 1-9  
Mx+B Scaling ............................................................................................... 1-9  
Alarms........................................................................................................... 1-9  
Totalizer Channel.......................................................................................... 1-9  
Alarm Outputs and Digital I/O...................................................................... 1-9  
Applications Software....................................................................................... 1-9  
Hydra Starter Package................................................................................... 1-10  
Hydra Logger ................................................................................................ 1-10  
Options and Accessories ................................................................................... 1-10  
Memory Card Reader.................................................................................... 1-10  
Connector Set, 2620A-100............................................................................ 1-10  
Setting Up the Instrument.................................................................................. 1-11  
Unpacking and Inspecting the Instrument..................................................... 1-11  
Adjusting the Handle .................................................................................... 1-12  
Connecting the Instrument to a Power Source.............................................. 1-12  
AC Operation............................................................................................ 1-13  
DC Operation............................................................................................ 1-13  
Input Channels .............................................................................................. 1-13  
Measurement Connections ................................................................................ 1-14  
Using Shielded Wiring.................................................................................. 1-14  
Crosstalk........................................................................................................ 1-14  
Universal Input Module Connections ........................................................... 1-14  
Alarm Outputs Connections.......................................................................... 1-17  
DC Power.................................................................................................. 1-17  
Alarm Outputs .......................................................................................... 1-17  
External Trigger Input .............................................................................. 1-17  
Digital I/O Connections ................................................................................ 1-18  
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2635A  
Users Manual  
Digital I/O................................................................................................. 1-18  
Totalizer Input .......................................................................................... 1-18  
Controls and Indicators ..................................................................................... 1-19  
Front Panel Controls ..................................................................................... 1-19  
Front Panel Indicators................................................................................... 1-19  
2
Front Panel Operations ..................................................................... 2-1  
Summary of Front Panel Operations................................................................. 2-5  
Configuring the Instrument for Operation......................................................... 2-6  
Turning the Power on.................................................................................... 2-6  
Selecting a Channel....................................................................................... 2-8  
Configuring a Measurement Channel................................................................ 2-8  
Configuring a Channel to Measure DC Volts............................................... 2-9  
Configuring a Channel to Measure AC Volts............................................... 2-10  
Configuring a Channel to Measure Resistance............................................. 2-11  
Configuring a Channel to Measure Frequency ............................................. 2-12  
Configuring a Channel to Measure Temperature.......................................... 2-13  
Thermocouples ......................................................................................... 2-13  
Resistance-Temperature Detectors........................................................... 2-13  
Thermocouple Restrictions:...................................................................... 2-13  
Resistance Temperature Detectors Restrictions:...................................... 2-13  
Configuring a Channel Off ........................................................................... 2-16  
Setting Operating Conditions............................................................................ 2-16  
Setting the Scan Interval ............................................................................... 2-17  
Setting the Measurement Rate ...................................................................... 2-18  
Setting the Alarms......................................................................................... 2-18  
Alarm Indications While Scanning........................................................... 2-18  
Alarm Indications While Monitoring ....................................................... 2-19  
Alarm Indications While Reviewing ........................................................ 2-19  
Clearing Alarm Parameters from a Channel............................................. 2-19  
Alarm Outputs for Channel 0 to 3 Using the Alarm Outputs Connector . 2-19  
Alarm Outputs for Channels 4 to 20 Using the Digital I/O Connector .... 2-19  
Alarms and Autoprinting.......................................................................... 2-20  
Alarms and Monitor-Alarm Triggering.................................................... 2-20  
Alarms and Mx+B Scaling ....................................................................... 2-20  
Setting the Mx+B Scaling............................................................................. 2-23  
Examples................................................................................................... 2-23  
Restrictions ............................................................................................... 2-23  
Clearing Mx+B Scaling from a Channel .................................................. 2-23  
Operating Modes ............................................................................................... 2-26  
Using the Scan Mode .................................................................................... 2-26  
Memory Card as a Data Destination......................................................... 2-26  
Memory Card Formatting......................................................................... 2-26  
Memory Card Capacity............................................................................. 2-26  
Memory Card Files................................................................................... 2-26  
Memory Card Exchange During Scanning............................................... 2-26  
Memory Card Data Extraction.................................................................. 2-27  
Memory Card Error Messages ...................................................................... 2-28  
Using the Monitor Mode............................................................................... 2-29  
Using the Review Mode................................................................................ 2-30  
Additional Features ........................................................................................... 2-31  
Scan Triggering Options ............................................................................... 2-31  
External Trigger........................................................................................ 2-31  
Monitor-Alarm Trigger............................................................................. 2-31  
ii  
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Contents (continued)  
Triggering Options and Memory Card Operation .................................... 2-31  
Totalizer Operation ....................................................................................... 2-32  
Digital Input/output Lines............................................................................. 2-33  
Setting Date and Time................................................................................... 2-34  
Reading Instrument Software Versions ........................................................ 2-35  
Returning to the Local Mode ........................................................................ 2-35  
Front Panel Key Lockout Options ................................................................ 2-36  
Instrument Interfaces......................................................................................... 2-36  
Memory Card Interface................................................................................. 2-36  
RS-232 Computer Interface .......................................................................... 2-37  
Using the RS-232 Computer Interface With a Printer .................................. 2-37  
Using the RS-232 Computer Interface With a Modem................................. 2-37  
3
Memory Card Operations .................................................................. 3-1  
Summary of Memory Card Operations ............................................................. 3-3  
Memory Card Files ....................................................................................... 3-3  
Setup Files..................................................................................................... 3-4  
Data Files ...................................................................................................... 3-4  
Memory Card Capacity................................................................................. 3-4  
Memory Card Battery ................................................................................... 3-5  
Inserting and Removing the Memory Card ....................................................... 3-5  
Inserting a Memory Card .............................................................................. 3-5  
Removing a Memory Card............................................................................ 3-5  
Changing the Memory Card During Scanning.............................................. 3-5  
Setting the Memory Card Write-protect Feature .......................................... 3-5  
Installing or Replacing the Memory Card Battery ............................................ 3-5  
Initializing a Memory Card ............................................................................... 3-7  
Recording Measurement Results During Scanning........................................... 3-8  
Setup File Procedures........................................................................................ 3-9  
Using Setup Store.......................................................................................... 3-9  
Using Setup Load.......................................................................................... 3-10  
Using Setup Erase ......................................................................................... 3-11  
Data File Procedures ......................................................................................... 3-12  
Using Data Open........................................................................................... 3-12  
Using Data Erase........................................................................................... 3-13  
Setup and Data Files Directory ......................................................................... 3-14  
Setup and Data File Current Status ................................................................... 3-15  
Memory Card File Operations to and from a PC .............................................. 3-16  
4
Computer Operations ........................................................................ 4-1  
Summary of Computer Operations.................................................................... 4-3  
Connecting the Instrument to a PC.................................................................... 4-3  
Configuring the Instrument for Computer Operations...................................... 4-5  
Configuring the PC for Computer Operations .................................................. 4-6  
Testing the Instrument/PC RS-232 Interface .................................................... 4-6  
Testing the RS-232 Interface Using Terminal Emulation (Windows) ......... 4-6  
Testing the RS-232 Interface Using Terminal Emulation (Generic) ............ 4-7  
Testing the RS-232 Interface Using Gwbasic............................................... 4-9  
Testing the RS-232 Interface Using Qbasic.................................................. 4-10  
Computer Interface Commands and Operation................................................. 4-12  
How the Instrument Processes Input............................................................. 4-12  
Input Terminators.......................................................................................... 4-12  
Input String Examples................................................................................... 4-13  
Sending Numeric Values to the Instrument .................................................. 4-13  
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2635A  
Users Manual  
How the Instrument Processes Output.......................................................... 4-13  
Status Registers............................................................................................. 4-14  
Instrument Event Register (IER) .............................................................. 4-14  
Standard Event Status Register (ESR)...................................................... 4-16  
Status Byte Register (STB)....................................................................... 4-17  
Computer Interface Command Set................................................................ 4-18  
Xmodem File Transfers ................................................................................ 4-18  
5
Printer Operations ............................................................................. 5-1  
Summary of Printer Operations......................................................................... 5-3  
Connecting the Instrument to a Printer.............................................................. 5-3  
Configuring for Printer Operations ................................................................... 5-5  
Printing Measurement Data and Memory Card Directory ................................ 5-6  
Problems?...................................................................................................... 5-6  
Printing Measurement Results During Scanning.......................................... 5-6  
Printing the Review Array ............................................................................ 5-8  
Printing the Directory of the Memory Card.................................................. 5-9  
6
7
Modem Operations ............................................................................ 6-1  
Summary of Modem Operations ....................................................................... 6-3  
Connecting the Modem to a PC for Modem Configuration.............................. 6-4  
Configuring the Instrument Modem for Modem Operations ............................ 6-4  
Connecting the Modem to an Instrument .......................................................... 6-6  
Configuring the Instrument for Modem Operations.......................................... 6-7  
Testing the RS-232/Modem Interface ............................................................... 6-8  
Maintenance....................................................................................... 7-1  
Introduction ....................................................................................................... 7-3  
Cleaning............................................................................................................. 7-3  
Line Fuse ........................................................................................................... 7-3  
Selftest Diagnostics and Error Codes................................................................ 7-4  
Performance Tests............................................................................................. 7-4  
Accuracy Verification Test........................................................................... 7-7  
Channel Integrity Test................................................................................... 7-8  
Thermocouple Measurement Range Accuracy Test ..................................... 7-9  
Four-Terminal Resistance Test..................................................................... 7-10  
Thermocouple Temperature Accuracy Test.................................................. 7-10  
Open Thermocouple Response Test ............................................................. 7-11  
RTD Temperature Accuracy Test................................................................. 7-13  
RTD Temperature Accuracy Test (Using Decade Resistance Source).... 7-13  
RTD Temperature Accuracy Test (Using DIN/IEC 751 RTD)................ 7-14  
Digital Input/Output Verification Tests........................................................ 7-15  
Digital Output Test ................................................................................... 7-15  
Digital Input Test...................................................................................... 7-16  
Totalizer Test............................................................................................ 7-17  
Totalizer Sensitivity Test.......................................................................... 7-18  
Dedicated Alarm Output Test ....................................................................... 7-18  
External Trigger Input Test........................................................................... 7-21  
Calibration......................................................................................................... 7-21  
Variations in the Display................................................................................... 7-22  
Service............................................................................................................... 7-22  
iv  
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Contents (continued)  
Appendices  
A Specifications.............................................................................................. A-1  
B Crosstalk Considerations ............................................................................ B-1  
C Binary Upload of Logged Data................................................................... C-1  
D RS-232 Cabling........................................................................................... D-1  
E
F
8-Bit Binary-Coded-Decimal Table............................................................ E-1  
Memory Card File Formats......................................................................... F-1  
G True RMS Measurements ........................................................................... G-1  
Index  
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2635A  
Users Manual  
vi  
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List of Tables  
Table  
Title  
Page  
1-1. Data Bucket Features............................................................................................. 1-6  
1-2. Options and Accessories........................................................................................ 1-11  
1-3. Front Panel Keys Description................................................................................ 1-21  
1-4. Annunciator Descriptions...................................................................................... 1-22  
2-1. Configuration Reset (Default) Settings ................................................................. 2-7  
2-2. Selftest Error Codes............................................................................................... 2-7  
2-3. Thermocouple Ranges ........................................................................................... 2-14  
2-4. TLL Alarm Outputs (Channels 0 to 3) .................................................................. 2-20  
2-5. TTL Alarm Outputs (Channels 4 to 20) ................................................................ 2-21  
3-1. Memory Card Error Codes .................................................................................... 3-6  
4-1. Instrument Event Register (IER) ........................................................................... 4-16  
4-2. Event Status Register (ESR).................................................................................. 4-17  
4-3. Status Byte Register (STB).................................................................................... 4-18  
4-4. Command and Query Summary............................................................................. 4-19  
4-5. Command and Query Reference............................................................................ 4-23  
7-1. Power-Up Error Codes........................................................................................... 7-4  
7-2. Recommended Test Equipment............................................................................. 7-6  
7-3. Performance Tests (Voltage, Resistance, and Frequency) .................................... 7-7  
7-4. Performance Tests for Thermocouple Temperature Function............................... 7-11  
7-5. Performance tests for RTD Temperature Function (Resistance Source)(ITS-90) 7-14  
7-6. Performance Tests for RTD Temperature Function (DIN/ IEC 751  
Amendment 2)(ITS-90).......................................................................................... 7-15  
7-7. Digital Input Values............................................................................................... 7-17  
A-1. DC Voltage Measurements - Resolution ............................................................... A-2  
A-2. DC Voltage Measurements - Accuracy ................................................................. A-2  
A-3. AC Voltage Measurements - Resolution ............................................................... A-4  
A-4. AC Voltage Measurements - Accuracy ................................................................. A-4  
A-5. Temperature Measurements - Accuracy (Thermocouples) (IPTS-68) .................. A-5  
A-6. Temperature Measurements - Accuracy (Thermocouples) (ITS-90) .................... A-6  
A-7. Temperature Measurements - Accuracy (RTDs) (IEC751 Amendment 2)  
(ITS-90................................................................................................................... A-7  
A-8. Temperature Measurements - Accuracy (RTDs) (IEC751 Amendment 1)  
(ITS-90) ................................................................................................................. A-7  
A-9. Temperature Measurements - Accuracy (RTDs) (IEC751) (IPTS-68).................. A-8  
A-10. AC Voltage Measurements - Resolution ............................................................... A-9  
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2635A  
Users Manual  
A-11. AC Voltage Measurements - Accuracy ................................................................. A-9  
A-12. AC Voltage Measurements.................................................................................... A-10  
A-13. Resistance Measurements - Resolution. ................................................................ A-11  
A-14. Resistance Measurements - Accuracy (Four-Wire)............................................... A-11  
A-15. Frequency Measurements-Resolution and Accuracy ............................................ A-12  
A-16. Frequency Measurements - Input Sensitivity ........................................................ A-12  
A-17. Typical Scanning Rate........................................................................................... A-13  
A-18. Autoranging Rates ................................................................................................. A-14  
C-1. Floating-Point Format............................................................................................ C-5  
E-1. 8-Bit Binary-Coded-Decimal................................................................................. E-2  
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List of Figures  
Figure  
Title  
Page  
1-1. Data Bucket Front and Rear Panels....................................................................... 1-7  
1-2. Typical Front Panel Display While Scanning ....................................................... 1-8  
1-3. Adjusting the Handle............................................................................................. 1-12  
1-4. Connecting the Instrument to a Power Source....................................................... 1-13  
1-5. Universal Input Module Connections.................................................................... 1-15  
1-6. Two-Terminal and Four-Terminal Connections.................................................... 1-16  
1-7. ALARM OUTPUTS connector ............................................................................. 1-17  
1-8. DIGITAL I/O Connector ....................................................................................... 1-18  
1-9. Front Panel Keys.................................................................................................... 1-19  
1-10. Primary Display..................................................................................................... 1-19  
1-11. Secondary Display................................................................................................. 1-20  
1-12. Annunciator Display.............................................................................................. 1-20  
2-1. How to use the Control/Annunciator Diagrams .................................................... 2-5  
2-2. Turning the Power On ........................................................................................... 2-6  
2-3. Selecting a Channel ............................................................................................... 2-8  
2-4. Configuring a Channel to Measure DC Volts........................................................ 2-10  
2-5. Configuring a Channel to Measure AC Volts........................................................ 2-11  
2-6. Configuring a Channel to Measure Resistance...................................................... 2-11  
2-7. Configuring a Channel to Measure Frequency...................................................... 2-12  
2-8. Configuring a Channel to Measure Temperature (Thermocouples)...................... 2-14  
2-9. Configuring a Channel to Measure Temperature (RTDs)..................................... 2-15  
2-10. Configuring a Channel Off .................................................................................... 2-16  
2-11. Setting the Scan Interval........................................................................................ 2-17  
2-12. Setting the Measurement Rate............................................................................... 2-18  
2-13. Setting the Alarms ................................................................................................. 2-22  
2-14. Setting the Mx+B Scaling...................................................................................... 2-24  
2-15. Using the Scan Mode............................................................................................. 2-27  
2-16. Memory Card Error Messages............................................................................... 2-28  
2-17. Using the Monitor Mode ....................................................................................... 2-29  
2-18. Using the Review Mode ........................................................................................ 2-30  
2-19. Scan Triggering Options........................................................................................ 2-32  
2-20. Totalizer Operation................................................................................................ 2-33  
2-21. Setting Date and Time ........................................................................................... 2-34  
2-22. Reading Instrument Software Versions................................................................. 2-35  
2-23. Returning to LOCAL Mode................................................................................... 2-35  
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2635A  
Users Manual  
2-24. Front Panel Key Lockout Options ......................................................................... 2-36  
3-1. Typical Memory Card............................................................................................ 3-3  
3-2. Front Panel Memory Card Percent Display........................................................... 3-5  
3-3. Initializing a Memory Card.................................................................................... 3-7  
3-4. Recording Measurement Results During Scanning............................................... 3-8  
3-5. Using SETUP STORE to Save Configuration Files.............................................. 3-9  
3-6. Using SETUP LOAD to Load Configuration Files............................................... 3-10  
3-7. Using SETUP ERASE to Delete Configuration Files ........................................... 3-11  
3-8. Using DATA OPEN to Save Measurement Data in a File.................................... 3-12  
3-9. Using DATA ERASE to Delete a Measurement Data File ................................... 3-13  
3-10. Using DIRECTORY to Examine SETUP and DATA files................................... 3-14  
3-11. Using STATUS to Examine SETUP and DATA Files.......................................... 3-15  
4-1. Connecting the Instrument to a PC........................................................................ 4-4  
4-2. Configuring the Instrument for Computer Operations .......................................... 4-5  
4-3. Overview of Status and Event Data Registers....................................................... 4-15  
4-4. Sample Program (GWBASIC)............................................................................... 4-57  
4-5. Sample Program (QBASIC)................................................................................... 4-59  
4-6. Sample Program (QuickC) (1of 5)......................................................................... 4-62  
5-1. Connecting the Instrument to a Printer.................................................................. 5-4  
5-2. Configuring the RS-232 Ports for Print Operations .............................................. 5-5  
5-3. Printing Measurement Results During Scanning................................................... 5-7  
5-4. Printing the Review Array..................................................................................... 5-8  
5-5. Printing the Memory Card Directory..................................................................... 5-10  
6-1. Overall PC-to-Instrument Modem Connection...................................................... 6-3  
6-2. Connecting the Modem to a PC............................................................................. 6-5  
6-3. Connecting the Modem to an Instrument .............................................................. 6-6  
6-4. Configuring the Instrument RS-232 Port for Modem Operations ......................... 6-7  
7-1. Replacing the Line Fuse ........................................................................................ 7-3  
7-2. Four-Terminal Connections to 5700A................................................................... 7-12  
7-3. Four-Terminal Connections to Decade Resistance Box........................................ 7-14  
7-4. Dedicated Alarms Output Test .............................................................................. 7-20  
7-5. External Trigger Test............................................................................................. 7-21  
C-1. ASCII String Decoding.......................................................................................... C-3  
C-2. Floating_Point Conversion .................................................................................... C-6  
C-3. Example ................................................................................................................. C-8  
D-1. Summary of RS-232 Connections ......................................................................... D-3  
D-2. Hydra Series II (DB-9) to PC (DB-9) RS-232 Connection (Generic) ................... D-4  
D-3. Hydra (DB-9) to PC (DB-25) RS-232 Connection................................................ D-5  
D-4. Hydra Series II (DB-9 to Modem (DB-25) RS-232 Connection ........................... D-6  
D-5. Hydra Series II (DB-9) to Printer (DB-25) RS-232 Connection ........................... D-7  
D-6. RS-232 DB-9 and DB-25 Connectors.................................................................... D-8  
G-1. Comparison of Common Waveforms .................................................................... G-2  
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CAUTION  
THIS IS AN IEC SAFETY CLASS 1 PRODUCT. BEFORE USING, THE GROUND WIRE IN THE  
LINE CORD OR THE REAR PANEL BINDING POST MUST BE CONNECTED FOR SAFETY.  
Interference Information  
This equipment generates and uses radio frequency energy and if not installed and used in strict  
accordance with the manufacturer’s instructions, may cause interference to radio and television  
reception. It has been type tested and found to comply with the limits for a Class B computing  
device in accordance with the specifications of Part 15 of FCC Rules, which are designed to  
provide reasonable protection against such interference in a residential installation.  
Operation is subject to the following two conditions:  
This device may not cause harmful interference.  
This device must accept any interference received, including interference that may cause  
undesired operation.  
There is no guarantee that interference will not occur in a particular installation. If this equipment  
does cause interference to radio or television reception, which can be determined by turning the  
equipment off and on, the user is encouraged to try to correct the interference by one of more of  
the following measures:  
Reorient the receiving antenna  
Relocate the equipment with respect to the receiver  
Move the equipment away from the receiver  
Plug the equipment into a different outlet so that the computer and receiver are on different  
branch circuits  
If necessary, the user should consult the dealer or an experienced radio/television technician for  
additional suggestions. The user may find the following booklet prepared by the Federal  
Communications Commission helpful: How to Identify and Resolve Radio-TV Interference  
Problems. This booklet is available from the U.S. Government Printing Office, Washington, D.C.  
20402. Stock No. 004-000-00345-4.  
Declaration of the Manufacturer or Importer  
We hereby certify that the Fluke Model 2635A Data Bucket is in compliance with BMPT Vfg  
243/1991 and is RFI suppressed. The normal operation of some equipment (e.g. signal  
generators) may be subject to specific restrictions. Please observe the notices in the users  
manual. The marketing and sales of the equipment was reported to the Central Office for  
Telecommunication Permits (BZT). The right to retest this equipment to verify compliance with the  
regulation was given to the BZT.  
Bescheinigung des Herstellers/Importeurs  
Hiermit wird bescheinigt, daβ Fluke Model 2635A Data Bucket in Übereinstimung mit den  
Bestimmungen der BMPT-AmtsblVfg 243/1991 funk-entstört ist. Der vorschriftsmäßige Betrieb  
mancher Geräte (z.B. Meßsender) kann allerdings gewissen Einschränkungen unterliegen.  
Beachten Sie deshalb die Hinweise in der Bedienungsanleitung. Dem Bundesamt für Zulassungen  
in der Telekcommunikation wurde das Inverkehrbringen dieses Gerätes angezeigt und die  
Berechtigung zur Überprüfung der Seire auf Einhaltung der Bestimmungen eingeräumt.  
Fluke Corporation  
xi  
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Safety Terms in this Manual  
This instrument has been designed and tested in accordance with iec publication 1010,  
safety requirements for electrical measuring, control and laboratory equipment. This user  
manual contains information, warnings, and cautions that must be followed to ensure  
safe operation and to maintain the instrument in a safe condition. Use of this equipment  
in a manner not specified herein may impair the protection provided by the equipment.  
The meter is designed for iec 664, installation category ii use. It is not designed for use  
in circuits rated over 4800va.  
Warning statements identify conditions or practices that could result in personal injury  
or loss of life.  
Caution statements identify conditions or practices that could result in damage to  
equipment.  
Symbols Marked on Equipment  
danger - high voltage.  
ground (earth) terminal.  
protective ground (earth) terminal. Must be connected to safety earth  
ground when the power cord is not used. See Chapter 2.  
attention - refer to the manual. This symbol indicates that information  
about usage of a feature is contained in the manual. This symbol appears  
in the following two places on the instrument rear panel:  
1. Ground binding post (left of line power connector). Refer to "Using  
External DC Power" in Chapter 2.  
2. Alarm outputs/digital i/o connectors. Refer to Appendix A,  
Specifications.  
Warning  
To avoid electric shock:  
When the input module is installed, consider all channels  
with connections as accessible terminals that may be  
hazardous live.  
Disconnect the input module before touching or changing  
external wiring.  
Remove inputs from live voltages before opening the input  
module.  
xii  
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Contents (continued)  
AC Power Source  
The instrument is intended to operate from an ac power source that will not apply more  
than 264v ac rms between the supply conductors or between either supply conductor and  
ground. A protective ground connection by way of the grounding conductor in the power  
cord is required for safe operation.  
DC Power Source  
The instrument may also be operated from a 9 to 16v dc power source when either the  
rear panel ground binding post or the power cord grounding conductor is properly  
connected.  
Use the Proper Fuse  
To avoid fire hazard, use only a fuse identical in type, voltage rating, and current rating  
as specified on the rear panel fuse rating label.  
Grounding the Instrument  
The instrument utilizes controlled overvoltage techniques that require the instrument to  
be grounded whenever normal mode or common mode ac voltages or transient voltages  
may occur. The enclosure must be grounded through the grounding conductor of the  
power cord, or if operated on battery with the power cord unplugged, through the rear  
panel ground binding post.  
Use the Proper Power Cord  
Use only the power cord and connector appropriate for the voltage and plug  
configuration in your country.  
Use only a power cord that is in good condition.  
Refer cord and connector changes to qualified service personnel.  
Do Not Operate in Explosive Atmospheres  
To avoid explosion, do not operate the instrument in an atmosphere of explosive gas.  
Do Not Remove Cover  
To avoid personal injury or death, do not remove the instrument cover. Do not operate  
the instrument without the cover properly installed. Normal calibration is accomplished  
with the cover closed, and there are no user-serviceable parts inside the instrument, so  
there is no need for the operator to ever remove the cover. Access procedures and the  
warnings for such procedures are contained in the service manual. Service procedures  
are for qualified service personnel only.  
Do Not Attempt to Operate if Protection may be Impaired  
If the instrument appears damaged or operates abnormally, protection may be impaired.  
Do not attempt to operate it. When in doubt, have the instrument serviced.  
xiii  
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Ten Minute Tour  
Introduction  
Note  
This manual contains information and warnings that must be followed to  
ensure safe operation and keep the instrument in safe condition.  
Data Bucket operation and operational features can be understood in about ten minutes  
by completing the following procedure. Prior to staring the procedure, connect the  
instrument to a power source (see Chapter 1) and connect the supplied test leads to the  
front panel jacks (Channel 0). Some steps terminate when you press the C key instead  
of the E key because the completed step is beyond the scope of this quick tour.  
However, all steps contain a figure reference in brackets [] for additional information.  
For example, the first step of applying power refers to [Figure 2-2], which describes  
three other ways of applying power (Configuration-Reset, Display-Hold, and  
Temperature-Toggle). Therefore, this procedure may be used for a quick instrument  
familiarization or as a basis for instrument applications.  
It is assumed that the instrument is being powered for the first time or a configuration-  
reset procedure cleared the instrument of configuration data. To apply a configuration-  
reset to the instrument, hold down the C key when turning on the power and keep  
holding until the meter “beeps” in acknowledgment.  
xiv  
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Ten Minute Tour (continued)  
Applying power. Press the power switch to  
apply power. Other power-on options include  
Configuration-Reset, Display-Hold, and  
Temperature-Toggle. [Figure 2-2]  
POWER  
Selecting a Channel. Up/down arrow keys  
select a channel from 0 to 20. Channel 0  
connections are on the front panel; Channels 1  
through 20 connections are via the rear-panel  
Universal Input Module. Select Channel 10.  
[Figure 2-3]  
CH  
20  
...  
10  
...  
0
Selecting a Function. Press the FUNC key to  
open the function menu. Up/down arrow keys  
select a function. Temperature unit °F/°C is set  
with the Temperature-Toggle Power-On  
procedure. Select VAC, then press ENTER.  
[Figure 2-5]  
SET FUNC  
FUNC  
OFF  
°F [°C]  
Hz  
VAC  
V DC  
ENTER  
Selecting a Measurement Scale. Up/down  
arrow keys select a measurement scale. AUTO  
indicates autoranging, where the instrument  
automatically selects the scale that provides the  
best measurement resolution. Scale values are  
maximum expected readings, e.g., the 30.000  
VAC scale is for measurements of 30 VAC or  
less. Select 150.00 V scale, then press ENTER.  
Channel 10 is now configured. [Figure 2-5]  
SET FUNC  
Auto  
150.00 V  
30.000 V  
3.0000 V  
300.00 mV  
ENTER  
A
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2635A  
Users Manual  
A
Selecting a Channel. Select Channel 0 with the  
up/down arrow keys. Notice each key entry is  
acknowledged with a short "beep." Try the  
left/right arrow keys and notice a long beep.  
Short beeps represent correct entries; long beeps  
represent incorrect entries. [Figure 2-3]  
CH  
20  
...  
10  
...  
0
Selecting a Function. Press FUNC to open the  
function menu, use up/down arrow keys to select  
, then press ENTER. [Figure 2-6]  
SET FUNC  
FUNC  
ENTER  
ENTER  
OFF  
°F [°C]  
Hz  
VAC  
V DC  
Selecting a Measurement Scale. Select the  
300.00 scale with up/down arrow keys, then  
press ENTER. [Figure 2-6]  
SET FUNC  
Auto  
10.000 M  
3.0000 M  
300.00 k  
30.000 k  
3.0000 k  
300.00  
Selecting  
a
Terminal  
Configuration.  
SET FUNC  
Resistance measurements for channels  
1
through 10 can use two channels (4 terminals) for  
increased precision. For channels 0 and 11 to  
20, only 2 terminal (2T) connections are allowed.  
Press ENTER. [Figure 2-6]  
2T  
4T  
ENTER  
B
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Ten Minute Tour (continued)  
B
MON  
Selecting the Monitor Mode. Press the MON  
MON  
key to enable monitoring. Up/down arrow keys  
select any configured channel for monitoring.  
When Channel 0 () is selected, touch the probe  
tips together to measure test lead resistance.  
Channel 10 (VAC) may have a small reading  
because the input is unterminated. Press MON to  
exit monitoring. [Figure 2-17]  
0
10  
MON  
Selecting the SCAN Mode. Press the SCAN  
key to enable scanning. The display will indicate  
which channel is being measured during the  
scan. Monitor or Review can be enabled during  
scanning. Measurement data can be routed to  
the memory card, printer, or PC for display or  
processing. Press SCAN to exit scanning.  
[Figure 2-15]  
SCAN  
0
SCAN  
SCAN  
10  
SHIFT  
Selecting the Single Scan Mode. Press the  
SHIFT key, release, then press the SCAN key to  
make a SINGLE measurement scan.  
[Figure 2-15]  
SCAN  
0
SCAN  
10  
C
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2635A  
Users Manual  
C
INTVL  
Setting the Scan Interval. Press the INTVL key  
to open the interval menu. Up/down and left/right  
arrow keys select 0:00:00 (default) to 9:99:99.  
The format is HOURS:MINUTES:SECONDS.  
The scan interval is the total time between the  
start of each measurement cycle. 0:00:00  
represents continuous scanning. Press CANCL  
to exit. [Figure 2-11]  
SET  
0:00:00  
CANCL  
REVIEW  
Selecting the Review Mode.  
Press the  
REVIEW  
REVIEW key to open the Review array. The  
Review array holds the last, maximum, and  
minimum readings during all previous scans for  
all configured channels. Up/down arrow keys  
select the channel, while left/right arrow keys  
select LAST, MAX, and MIN. To CLEAR the  
Review array, press the SHIFT key, release,  
then press the REVIEW key. The Review array  
is cleared automatically by changing any  
parameter on any channel (including  
Measurement Rate). Press CANCL to exit.  
[Figure 2-18]  
LAST MIN MAX  
0
10  
SHIFT  
REVIEW  
CANCL  
Select Channel 10. Select Channel 10 with the  
up/down arrow keys. [Figure 2-3]  
CH  
20  
...  
10  
...  
0
D
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Ten Minute Tour (continued)  
D
ALRM  
Selecting Alarms. Press the ALRM key to open  
SET ALARM  
the alarm menu. Each configured channel can  
have two alarm limits assigned. An alarm is set  
when a reading is below or above an alarm limit.  
Configuration starts with an alarm limit selection,  
1 or 2. Press CANCL to exit. [Figure 2-13]  
1
2
CANCL  
Mx+B  
Setting Mx+B Scaling. Press the Mx+B key to  
open the Mx+B menu. Up/down and left/right  
arrow keys select the digits for the first parameter  
(M) (default +001.00). The effect of Mx+B scaling  
is to take a measurement (x) and modify it by  
multiplying the measurement with M and then  
adding an offset B (configured after M is set). For  
SET Mx+B  
M
+001.00  
example, Mx+B=+1.5x+25 applied to  
a
measurement of 20.000 would display  
1.5(20.000) + 25 = 55.000. Press CANCL to exit.  
[Figure 2-14]  
CANCL  
SHIFT  
Selecting the Measurement Rate. Press the  
SHIFT key, release, then press the Right Arrow  
key to open the RATE menu. During the  
measurement portion of the scan interval, the  
measurement rate can be FASt (Fast) or SLO  
RAtE  
FASt  
SLO  
(Slow).  
The slow rate gives full 5-digit  
measurement resolution, while the fast rate gives  
only 4-digit resolution. The advantage of a fast  
measurement rate is more readings during  
continuous scanning or low scan intervals. Press  
CANCL to exit. [Figure 2-12]  
CANCL  
E
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Ten Minute Tour (cont)  
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2635A  
Users Manual  
E
SHIFT  
INTVL  
Setting Date and Time. Press the SHIFT key,  
release, then press the INTVL key to open the  
date and time (CLOCK) menu. Up/down and  
left/right arrow keys select the YEAR 00 to 99.  
For the complete procedure, this is followed by  
MONTH:DAY and HOURS:MINUTES. Press  
CANCL to exit. [Figure 2-21]  
yEAR  
94  
CANCL  
Selecting the Totalizer Feature. Press the  
TOTAL key to open the totalizer display. The  
totalizer operates independently as a separate  
instrument function. Contact closures or voltage  
totAL  
0
TOTAL  
SHIFT  
transitions between pins Σ and  
on the rear  
panel DIGITAL I/O connector are totaled and  
displayed by pressing the TOTAL key. To ZERO  
the total (already 0 in this example), press the  
SHIFT key, release, then press the TOTAL key  
again. Press CANCL to exit. [Figure 2-20]  
TOTAL  
CANCL  
F
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Ten Minute Tour (continued)  
F
SHIFT  
MON  
Selecting Triggering Options. Press the SHIFT  
tRIg  
ALAr  
On  
OFF  
key, release, then press the MON key to open  
the TRIGS option menu. A trigger option can  
trigger scanning, instead of using the SCAN key.  
OFF indicates no triggering option; ON indicates  
the external trigger option is active (a contact  
closure or voltage transition between pins TR and  
on the rear panel ALARM OUTPUTS connector);  
ALAr (Alarm) indicates scan triggering when a  
monitored channel goes into Alarm. Press  
CANCL to exit. [Figure 2-19]  
CANCL  
SHIFT  
LIST  
Setting the Communication Parameters.  
Press the SHIFT key, release, then press the  
LIST key to open the COMM menu. The  
communication parameters configure the rear-  
panel RS-232 interface for printer and PC  
operations. The first selection is bAUd (Baud)  
with rates from 300 to 38400 baud. For the  
complete procedure, this is followed by parity,  
flow control and echo. Press CANCL to exit.  
[Figure 5-2]  
bAUd  
38400  
...  
300  
CANCL  
G
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2635A  
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G
LIST  
Setting the LIST Parameters. Press the LIST  
key to open the LIST menu. LIST is used to print  
out all the measurements from the Review Array,  
or print out a directory of all the files on the  
memory card by selecting dir (Directory). To use  
LIST, a printer (or PC) must be connected to the  
RS-232 port. Press CANCL to exit. [Figure 5-4]  
LISt  
dir  
LASt  
CANCL  
SHIFT  
FILES  
Setting the DESTINATION Parameter. Press  
the SHIFT key, release, then press the FILES  
key to open the MODE menu. CArd (Card)  
routes data to the memory card; Print (Print)  
routes data to the RS-232 connector to a printer  
(or PC); both (Both) routes data to both  
destinations, and nonE (None) to neither  
destination. Select CArd and press ENTER.  
[Figure 5-3]  
dESt  
both  
Print  
CArd  
nonE  
ENTER  
Selecting the Destination Mode. ALL (All)  
sends all measurement data to the destination  
device (Memory Card in this example); ALAr  
(Alarm) send all measurement data to the  
destination device when any scanned channel is  
in alarm; trAnS (Transition) sends all  
measurement data to the destination device  
when any scanned channel transitions into or out  
of an alarm condition. Press CANCL to exit.  
[Figure 5-3]  
MODE  
trAnS  
ALAr  
ALL  
CANCL  
H
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Ten Minute Tour (continued)  
H
FILES  
Selecting the File Options. Press the FILES  
key to open the Files menu. This menu selects  
the memory card functions. SEtUP (Setup)  
FILES  
Init  
StAt  
dir  
dAtA  
SEtUP  
selects  
card  
functions  
for  
instrument  
configuration files (SEtxx); dAtA (Data) selects  
card functions for measurement data files  
(dAtxx); dir (Directory) lists the number of  
kilobytes free on the card and the name and size  
of each SEtxx and dAtxx file; StAt (Status) lists  
which SEtxx and dAtxx files are currently active  
and percentage of the card that is used; Init  
(Initialize) formats a blank card or erases and  
formats a used card. Press CANCL to exit.  
[Figure 3-3]  
CANCL  
op79_9f.eps  
Ten Minute Tour (cont)  
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2635A  
Users Manual  
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Chapter 1  
Preparation for Use  
Title  
Page  
Introduction ....................................................................................................... 1-5  
Operating Modes ............................................................................................... 1-5  
Front Panel Operation................................................................................... 1-7  
Memory Card Operation ............................................................................... 1-7  
Computer Operation...................................................................................... 1-8  
Printer Operation........................................................................................... 1-8  
Modem Operation ......................................................................................... 1-8  
Measurement Capabilities................................................................................. 1-9  
Mx+B Scaling ............................................................................................... 1-9  
Alarms........................................................................................................... 1-9  
Totalizer Channel.......................................................................................... 1-9  
Alarm Outputs and Digital I/O...................................................................... 1-9  
Applications Software....................................................................................... 1-9  
Hydra Starter Package................................................................................... 1-10  
Hydra Logger ................................................................................................ 1-10  
Options and Accessories ................................................................................... 1-10  
Memory Card Reader.................................................................................... 1-10  
Connector Set, 2620A-100............................................................................ 1-10  
Setting Up the Instrument.................................................................................. 1-11  
Unpacking and Inspecting the Instrument..................................................... 1-11  
Adjusting the Handle .................................................................................... 1-12  
Connecting the Instrument to a Power Source.............................................. 1-12  
AC Operation............................................................................................ 1-13  
DC Operation............................................................................................ 1-13  
Input Channels .............................................................................................. 1-13  
Measurement Connections ................................................................................ 1-14  
Using Shielded Wiring.................................................................................. 1-14  
Crosstalk........................................................................................................ 1-14  
Universal Input Module Connections ........................................................... 1-14  
Alarm Outputs Connections.......................................................................... 1-17  
DC Power.................................................................................................. 1-17  
Alarm Outputs .......................................................................................... 1-17  
External Trigger Input .............................................................................. 1-17  
Digital I/O Connections ................................................................................ 1-18  
Digital I/O................................................................................................. 1-18  
1-1  
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2635A  
Users Manual  
Totalizer Input .......................................................................................... 1-18  
Controls and Indicators ..................................................................................... 1-19  
Front Panel Controls ..................................................................................... 1-19  
Front Panel Indicators................................................................................... 1-19  
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Preparation for Use  
Introduction  
1
1-3  
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2635A  
Users Manual  
REVIEW  
LAST  
SERIES II  
HYDRA  
CH  
mA  
mVDCAC  
Hz  
Mk  
V
COM  
REVIEW  
CLEAR  
FILES  
MODE  
INTVL  
SCAN  
CLOCK  
ALRM  
FUNC  
Mx+B  
SINGLE  
300V  
MAX  
RATE  
MON  
TOTAL  
ZERO  
ENTER  
LIST  
SHIFT  
CANCEL  
TRIGS  
COMM  
LOCAL  
BATT  
BUSY  
OP80F.EPS  
1-4  
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Preparation for Use  
Introduction  
1
NOTE  
This manual contains information and warnings that must be followed to  
ensure safe operation and keep the instrument in safe condition.  
Introduction  
The Fluke 2635A Hydra Series II Data Bucket is a 21-channel data logging instrument  
that measures and records the following electrical and physical parameters: dc volts, ac  
volts, resistance, frequency, and temperature. Temperature measurements are via  
thermocouples or resistance-temperature detectors (RTDs). Other parameters can be  
measured with an appropriate transducer, such as air pressure/vacuum (using a Fluke  
PV350 transducer module) or DC current (using a Fluke 2600A-101 shunt resistor).  
When the instrument scans channels configured for measurement, readings can be  
displayed, printed out, and recorded. Virtually any analog input may be applied without  
external signal conditioning. The inputs for channels 1 through 20 are via a Universal  
Input Module, which plugs into the rear of the unit for a quick connect/disconnect  
capability. Channel 0 measurements are via the front panel input jacks using test leads  
(supplied). For a quick introduction to the operation of the instrument, complete the Ten-  
Minute Tour at the front of this manual. A summary of the Hydra Series II Data Bucket  
features is provided in Table 1-1 and complete specifications in Appendix A. Figure 1-1  
shows the instrument front and rear panels.  
Operating Modes  
The Data Bucket may be used in a wide variety of applications using one or more of five  
operating modes:  
Front Panel Operation  
Memory Card Operation  
Computer Operation  
Printer Operation  
Modem Operation  
1-5  
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2635A  
Users Manual  
Table 1-1. Data Bucket Features  
Channel Scanning  
Can be continuous scanning, scanning at an interval time, single scans, or triggered (internal or  
external) scans. Channel Monitoring may be used while scanning.  
Channel Monitoring  
Make measurements on a single channel and view these measurements on the display.  
Memory Card  
Store measurement data and meter configuration setup data on a removable nonvolatile RAM  
card.  
Multi-Function Display  
Primary display shows measurement readings; also used when setting numeric parameters.  
Secondary display used for numeric entries, channel number selection and display, status  
information, and operator prompts.  
Annunciator display used to show measurement units, alarms review parameters, remote status,  
and configuration information.  
Front-Panel Operation  
Almost all operations can be readily controlled with the front panel keys.  
Measurement Input Function and Range  
Volts dc (VDC), volts ac (VAC), frequency (HZ), and resistance (e) inputs can be specified in a  
fixed measurement range. Autoranging, which allows the instruments to use the measurement  
range providing the optimum resolution, can also be selected.  
Temperature Measurement  
Thermocouple types J, K, E, T, N, R, S and B, and Hoskins Engineering Co. type C are supported.  
Also, DIN/IEC 751 Platinum RTDs are supported.  
Totalize Events on the Totalizing Input  
Alarm Limits and Digital Output Alarm Indication  
Four-Terminal Resistance Measurements (Channels 1 through 10 only)  
RS-232 Computer Interface Operation  
Measurement Rate Selection  
Nonvolatile Memory  
Storage of minimum, maximum, and most recent measurements for all scanned channels.  
Storage of Computer Interface setup, channel configurations, and calibration values.  
Internal storage of measurement data: storage for 100 scans of up to 21 channels, accessible only  
through the computer interface.  
1-6  
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Preparation for Use  
Operating Modes  
1
Ground Terminal.  
Connects mainframe  
to ground.  
AC Power Connector.  
Connect to any line source  
of 90 to 264 VAC (50/60 Hz).  
Universal Input Module.  
Directly wires 20 analog inputs  
(Channels 1 to 20) without  
external signal conditioning.  
FOR FIRE PROTECTION  
REPLACE WITH T 1/8A 250V (SLOW) FUSE  
CAUTION  
MODEL: 2620A  
25A  
2635A  
90-264V  
50/60 Hz  
15VA  
!
IEC 664 INSTALLATIONCATEGORY II  
ALARM OUTPUTS  
DIGITAL I/O  
RS-232C  
IEEE STD-488 PORT  
+ –  
0
1
2
3 TR  
0
1
2
3
4
5
6
7
Σ
9
5
8
7
6
1
4
3
2
+30V  
!
9-16 V  
DC PWR  
SH1, AH1, T5, L4, SR1, RL1, DC1, DT1, PP0, C0, E1  
MEETS Vfg. 243/1991  
COMPLIES WITHFCC-15B  
[DSR]  
[RTS]  
TX  
GND  
RX  
[2635A ONLY] [CTS] DTR  
Alarm Outputs Connector.  
Digital I/O Connector.  
Outputs alarms for  
channels 4 to 20 (default),  
inputs totalizer (Σ and ).  
RS-232C.  
Interfaces instrument with  
a printer, PC or modem.  
Outputs alarms for channels 0 to 3,  
DC power inputs for DC operation  
(9 to 16V dc), inputs external scan  
trigger (TR and ).  
op01f.eps  
Figure 1-1. Data Bucket Front and Rear Panels  
Front Panel Operation  
Front panel operations include configuration of channels in preparation for scanning  
operations and simple multimeter operation by placing the instrument in the Monitor  
mode then using the front panel jacks and test leads (channel 0) for measurements. Front  
panel operations are discussed in Chapter 2.  
Memory Card Operation  
An adjunct to stand-alone front panel use are operations that use the memory card  
feature. The memory card is a Static Random Access Memory (SRAM) device that plugs  
into a slot on the Data Bucket front panel. An internal battery maintains the integrity of  
the stored data. An empty 256K-byte card stores 8500 scans of 4 channels, 4500 scans of  
10 channels, or 2500 scans of 20 channels. A typical display while scanning using the  
memory card is shown in Figure 1-2. The PC-compatible memory card can be used to  
store measurement files and configuration files. Data extraction from the card requires a  
1-7  
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2635A  
Users Manual  
personal computer (PC), where data can be sent from the Data Bucket to the PC over an  
RS-232 link (up to a 38,400 baud rate), or the card can be removed and taken to a PC  
equipped with a memory card reader (see Options and Accessories). Memory card  
operations are discussed in Chapter 3.  
ALARM Annunciator.  
Indicates that one (or  
more) of the scanned  
channels is in alarm.  
18 (Channel) Scanned.  
Indicates the channel  
being measured during  
channel scanning.  
SCAN Annunciator.  
Indicates the instrument is  
in the Scan mode (vs  
Monitor or Review mode).  
SCAN  
ALARM  
PRN CH  
PRN (Print) Annunciator.  
Indicates the destination  
for the data is the memory  
card or printer.  
Memory Card Status.  
Card has used 42% of its  
capacity. After 99%, FULL  
is displayed.  
CH (Channel) Annunciator.  
Indicates the number in the  
secondary display is a  
channel.  
op02f.eps  
Figure 1-2. Typical Front Panel Display While Scanning  
Computer Operation  
The Data Bucket can serve as a front-end data acquisition unit for PC-based operations,  
operating over an RS-232 link. The applications software for operating the RS-232 link  
includes the supplied Hydra Starter Package (Starter) and optional Hydra Logger  
(Logger) (see "Applications Software" below). Computer operations are discussed in  
Chapter 4.  
Printer Operation  
Measurement data from the Data Bucket can be routed to a printer via an RS-232 link.  
At the completion of each scan cycle, measurement data is printed, providing hardcopy  
output. Any compatible printer with a serial input may be used. Printers with a parallel  
input may be used if they are equipped with a serial-to-parallel adapter. Printer  
operations are discussed in Chapter 5.  
Modem Operation  
An RS-232 link between the Data Bucket and a modem allows data transfers over  
telephone lines. Operation is similar to computer operations, except there is a modem  
link instead of a direct RS-232 connection. The modem may be electronic or  
programmable/electronic (Hayes-compatible). Modem operations are discussed in  
Chapter 6.  
1-8  
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Preparation for Use  
Measurement Capabilities  
1
Measurement Capabilities  
Before scanning is enabled, the Data Bucket channels are configured for measuring the  
selected electrical or physical parameter (volts dc, volts ac, temperature, etc.). Readings  
have five digits of resolution, for example, 15.388 VAC. Scanning collects measurement  
data, while the monitor mode can monitor a channel with or without scanning. The  
review mode stores the maximum, minimum and last readings. Mx+B scaling and alarm  
attributes can be applied to each configured channel. A totalizer channel is supplied as a  
separate feature, and digital I/O functions are provided by the rear panel connectors,  
ALARM OUTPUTS, and DIGITAL I/O.  
Mx+B Scaling  
The Mx+B scaling attribute allows readings to be modified to better represent what is  
being measured. The M represents a multiplier and B represents an offset. For example,  
a normal reading of 3 volts can be multiplied by M=+100 and offset by B=-25, to display  
275 (3x100 - 25= 275). Mx+B scaling can be applied to any configured channel. This  
feature is especially useful to scale transducer outputs for exact measurement displays.  
Alarms  
The alarms attribute allows readings that rise or fall below preset levels to alert the  
operator and trigger an action. For example, if you are monitoring temperature and want  
to have 100ºC cause an alarm condition, this can be programmed as part of the channel  
configuration. Alarm conditions are reported as part of the measurement scan data and  
can be used to trigger scanning and assert a logic low on a rear panel ALARM  
OUTPUTS or DIGITAL I/O connector terminal for interface with external equipment.  
Two alarms can be assigned to any configured channel. If Mx+B scaling is applied, the  
alarms are based on the scaled values.  
Totalizer Channel  
The totalizer channel counts contact closures or voltage transitions. The maximum count  
is 65,535. The connection is at the rear panel ALARMS OUTPUTS connector, terminals  
SUM and GROUND. The Data Bucket continuously samples the totalizer input on the  
rear panel, independently from Hydra's scanning and other activities.  
Alarm Outputs and Digital I/O  
Alarm outputs are available on the rear panel ALARM OUTPUTS and DIGITAL I/O  
connectors. The four ALARM OUTPUT lines are permanently assigned to signal alarms  
for channels 0, 1, 2, and 3. The eight DIGITAL I/O lines can be used to signal alarm  
conditions for channels 4 to 20. All input/output lines are transistor-transistor-logic  
(TTL) compatible. For operations that do not use a computer interface, these are the only  
functions of the ALARM OUTPUTS and DIGITAL I/O connections. When a computer  
interface is used, the DIGITAL I/O lines can be assigned in the applications software for  
a variety of inputs or outputs. The ALARM OUTPUTS can also be assigned for I/O  
operations if the dedicated alarm function is not used (which has priority).  
Applications Software  
PC applications software Hydra Starter (supplied) and Hydra Logger Package (Logger)  
(optional) operate the instrument via the RS-232 computer interface. The software  
packages are described in separate technical manuals; however, each is summarized  
below.  
1-9  
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2635A  
Users Manual  
An extensive command set allows the user to develop custom software in GWBASIC,  
QBASIC, and QuickC. The command set is discussed in Chapter 4.  
Hydra Starter Package  
Starter is a DOS based, menu-driven software package used to transfer configuration  
data from and to the instrument, log measurement data collected by the instrument,  
extract data from the memory card, and manage the acquired data. During operation,  
Starter displays readings of all channels in real time and can automatically log the data to  
a Lotus 1-2-3 compatible file.  
Hydra Logger  
Hydra Logger (model 2635A-901) is an optional Windows-based package that allows  
complete setup, data collection and data conversion from up to two Hydra units. Logger  
communicates over the RS-232 port on a personal computer and may be used with  
telephone models. Hydra Logger with Trending (model 2635A-902) includes a  
comprehensive trending package that simulates a chart recorder. A brochure with  
complete details is available.  
Options and Accessories  
Options and accessories include measurement transducers, cables, applications software,  
carrying case and other items, all of which are summarized in Table 1-2.  
Memory Card Reader  
Data Bucket measurement data and configuration setups may be stored on a memory  
card that is inserted into the slot on the instrument front panel (see Figure 1-1). To  
review and analyze the recorded data, the memory card data can be routed to a PC via  
the RS-232 interface, or the memory card can be removed and taken to a PC equipped  
with a memory card reader. The memory card reader (optional) is external to the PC and  
connects to a PC parallel port (LPT1, LPT2, etc.). The memory card reader is configured  
as another PC drive, e.g., the D: drive. Memory card files include data files  
(dAtxx.HYD) and configuration setups (SEtxx.HYD). The PC manipulates these files  
using applications software Starter (supplied) and Logger (optional). The selected  
memory card reader must read SRAM cards and meet Personal Computer Memory Card  
International Association (PCMCIA)/Japan Electronics Industrial Development  
Association (JEIDA) standards. This memory card application meets PCMCIA standards  
release 2.0.  
Connector Set, 2620A-100  
The 2620A-100 is a complete set of input connectors: one Universal Input Module, one  
ALARM OUTPUTS connector, and one DIGITAL I/O connector. The use of additional  
connector sets allows quick equipment interface to several wiring setups.  
1-10  
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Preparation for Use  
Setting Up the Instrument  
1
Table 1-2. Options and Accessories  
DESCRIPTION  
MODEL  
2635A-901  
Hydra Logger Software (Windows)  
2635A-902  
2640A-904  
2620A-100  
Hydra Logger Software with Trending (includes 2640A-904)  
Trend Link for Fluke Software  
I/O Connector Set; includes Universal Input Module, Digital I/O Connector and  
Alarm Output Connector  
2620A-101  
10 Ohm Shunt Set (set of 12 shunts)  
263XA-803  
263XA-804  
263XA-805  
263XA-806  
263XA-807  
Memory Card Reader. Connects to PC parallel printer port  
256Kb SRAM Memory Card (one included with instrument)  
1Mb SRAM Memory Card  
2Mb SRAM Memory Card  
4Mb SRAM Memory Card  
RS40  
RS41  
RS42  
RS43  
RS-232 Cable. DB9 to DB25  
RS-232 Modem Cable. DB9 to DB25  
RS-232 Printer Cable. DB9 to DB25  
RS-232 Cable. DB9 to DB9  
C40  
Soft Carrying Case  
Transit Case  
C44  
M00-200-634  
26XXA-600  
688868  
Rackmount Kit  
Portable Battery Pack  
Hydra Series II Service Manual  
Setting Up the Instrument  
Setting up the instrument includes all preparatory information, from unpacking the  
instrument to application of power.  
Unpacking and Inspecting the Instrument  
The following items are included in the shipping container:  
Model 2635A Data Bucket instrument  
This manual  
Starter Applications software (floppy disks and manual)  
Universal Input Module  
ALARM OUTPUTS and DIGITAL I/O connectors  
Channel 0 (front panel)TL70A test leads  
1-11  
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2635A  
Users Manual  
Line power cord  
Type "T" Thermocouple  
256K-byte Memory Card  
Carefully remove the instrument from its shipping container and inspect the instrument  
for possible damage or missing items. If the instrument is damaged or anything is  
missing, contact the place of purchase immediately. Save the container and packing  
material in case you have to return the instrument.  
Rotate the rear feet of the instrument 180 degrees so that their support pads extend  
slightly below the bottom of the case.  
Adjusting the Handle  
The handle can be positioned to four angles: one for carrying, two for viewing, and one  
for handle removal. To change the angle, simultaneously pull both handle ends outward  
to hard stops (about 1/4-inch on each side) and then rotate the handle to one of the four  
stop positions shown in Figure 1-3. With the handle in the straight-up removal position,  
you can disengage and free one handle side at a time.  
2. Alternative Viewing Position  
1. Viewing Position  
Pull One End Out and Towards You.  
Then Pull the Other End Out.  
4. Removal Position  
(to Remove, Pull Ends Out)  
COM  
V
3. Carrying Position  
300V  
MAX  
op03f.eps  
Figure 1-3. Adjusting the Handle  
Connecting the Instrument to a Power Source  
The instrument can be connected to an ac or dc source. Connections are shown in Figure  
1-4 and described below.  
1-12  
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Preparation for Use  
Setting Up the Instrument  
1
LINE CORD (AC OPERATION)  
FOR FIRE PROTECTION  
REPLACE WITH T 1/8A 250V (SLOW) FUSE  
CAUTION  
MODEL: 2620A  
5A  
2635A  
90-264V  
50/60 Hz  
15VA  
!
IEC 664 INSTALLATIONCATEGORY II  
ALARM OUTPUTS  
DIGITAL I/O  
RS-232C  
IEEE STD-488 PORT  
+ –  
0
1
2
3
TR  
0
1
2
3
4
5
6
7
Σ
9
5
8
7
6
1
4
3
2
+30V  
!
9-16 V  
DC PWR  
SH1, AH1, T5, L4, SR1, RL1, DC1, DT1, PP0, C0, E1  
MEETS Vfg. 243/1991  
COMPLIES WITHFCC-15B  
[DSR]  
[RTS]  
TX  
[2635A ONLY] [CTS] DTR RX  
GND  
EXTERNAL BATTERY (DC OPERATION)  
WARNING: If voltages greater than 30V are to be measured, a safety ground must be attached  
to the rear panel ground connector when the instrument is operated from battery power.  
op04f.eps  
Figure 1-4. Connecting the Instrument to a Power Source  
Warning  
To avoid shock hazard, connect the instrument power cord to a  
power receptacle with earth ground.  
AC Operation  
Plug the line cord into the connector on the rear of the instrument. The instrument  
operates on any line voltage between 90 and 264V ac without adjustment, and at any  
frequency between 45 and 440 Hz. However, the instrument is warranted to meet  
published specifications only at 50 or 60 Hz.  
DC Operation  
The instrument may be operated from a DC voltage between 9 and 16 volts, consuming a  
nominal 4 watts. Connection is made at the rear panel ALARM OUTPUTS connector,  
pins (+) and (-). If both ac and dc sources are connected simultaneously, ac is used if it  
exceeds approximately 8.3 times dc. Automatic switchover occurs between ac and dc  
without interruption.  
Warning  
If voltages greater than 30V are to be measured, a safety  
ground must be attached to the rear panel ground connector  
when the instrument is operated from battery power.  
Input Channels  
The instrument provides one input (channel 0) on the front panel and 20 inputs (channels  
1 through 20) through a connector on the rear panel. Channels 0, 1, and 11 can measure a  
maximum of 300V dc or ac rms; all other channels can measure a maximum of 150V dc  
or ac rms.  
1-13  
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2635A  
Users Manual  
Caution  
Do not exceed the specified input voltage levels or equipment  
damage could result.  
Measurement Connections  
W Warning  
To avoid electric shock:  
When the input module is installed, consider all channels  
with connections as accessible terminals that may be  
hazardous live.  
Disconnect the input module before touching or changing  
external wiring.  
Input connections include the front panel terminals (channel 0), rear panel connections  
using the Universal Input Module (channels 1 through 20), and I/O functions using the  
ALARM OUTPUTS and DIGITAL I/O connectors. The instrument is protected from  
channel configuration errors. For example, accidentally applying 300V ac to a channel  
configured for resistance measurements will not damage the instrument.  
Using Shielded Wiring  
Shielded wires and sensors (such as thermocouples) should be used in environments  
where "noisy" voltage sources are present. When shielded wiring is used, the shield is  
normally connected to the L (low) input terminals for each channel. Alternate  
configurations should be examined for each equipment application.  
Crosstalk  
The instrument allows the mixing of various types of measurement. A phenomenon  
known as crosstalk can cause one signal to interfere with another and thereby introduce  
measurement errors. To reduce the effects of crosstalk in making measurement  
connections, do the following:  
Keep any input wiring carrying ac volts signals physically separate from the input  
wiring of other sensitive channels.  
Avoid connecting inputs with ac volts signals adjacent to sensitive channel inputs.  
Leave unconnected channels between the inputs, if possible.  
Avoid connecting inputs with ac volts signals to any channel 10 numbers away from  
a sensitive channel (i.e., 4-terminal input channels).  
Avoid tying L (low) or (especially) H (high) inputs of a sensitive channel to earth  
(chassis) ground. This is very important in resistance measurements.  
Avoid high-source impedances on sensitive channels, or minimize the capacitance of  
the sensitive channel to earth (chassis) ground for high impedance inputs.  
Whenever high ohms measurements (>10 k) must be made accurately, avoid  
connecting any inputs carrying ac volts signals.  
Measurement errors introduced by crosstalk are discussed in Appendix B.  
Universal Input Module Connections  
For channels 1 through 20, use the H (high) and L (low) inputs on the rear panel  
Universal Input Module, as shown in Figure 1-5. Perform the following procedure to  
make connections to the Universal Input Module:  
1-14  
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Preparation for Use  
Measurement Connections  
1
STRAIN RELIEF  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
1
2
3
4
5
6
7
8
9
10  
op05f.eps  
Figure 1-5. Universal Input Module Connections  
Warning  
Inputs may be connected to live voltages. To avoid electric  
shock, remove inputs from live voltages before opening this  
module.  
1. Remove the module from the rear panel by pressing the release tab on the bottom of  
the module and then pulling the module out of its connector.  
2. Loosen the two large screws on top and open the module  
3. Connect the wires to H (high) and L (low) for each channel.  
4. Thread these wires through the strain-relief pins and out the back of the module.  
5. Close the module cover, secure the screws, and insert the module in the connector at  
the rear of the instrument until it latches in place.  
Note  
Channel 0 on the front panel does not support thermocouple  
measurements.  
Resistance and RTD measurements can be made with two terminals (one channel) or  
four terminals (two channels). The four-terminal connection provides increased accuracy  
(nominal 1%) over the two-terminal connection. Refer to Figure 1-6.  
1-15  
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2635A  
Users Manual  
2-WIRE (2T) CONNECTION  
11 12 13 14 15 16 17 18 19 20  
H L H L H L H L H L H L H L H L H L H L  
SOURCE  
(4-WIRE)  
H L H L H L H L H L H L H L H L H L H L  
SENSE  
(4-WIRE)  
1
2
3
4
5
6
7
8
9
10  
RESISTANCE  
OR  
RTD SOURCE  
USE H AND L TERMINALS FOR ANY CHANNEL.  
• CHANNEL 0 ON FRONT PANEL  
• CHANNELS 1 THROUGH 20 ON REAR  
PANEL INPUT MODULE (CHANNEL 8 SHOWN HERE).  
4-WIRE (4T) CONNECTION  
11 12 13 14 15 16 17 18 19 20  
H L H L H L H L H L H L H L H L H L H L  
SOURCE  
(4-WIRE)  
H L H L H L H L H L H L H L H L H L H L  
SENSE  
(4-WIRE)  
1
2
3
4
5
6
7
8
9
10  
RESISTANCE  
OR  
RTD SOURCE  
USE H AND L TERMINALS FOR TWO CHANNELS ON REAR PANEL INPUT MODULE.  
CONNECTIONS FOR CHANNEL 8 ARE SHOWN HERE WITH CHANNEL 18 PROVIDING  
THE ADDITIONAL TWO CONNECTIONS.  
FOR EACH 4-WIRE CONNECTION, ONE SENSE CHANNEL (1 THROUGH 10) AND  
ONE SOURCE CHANNEL (SENSE CHANNEL NUMBER +10 = 11 THROUGH 20) ARE USED.  
op06f.eps  
Figure 1-6. Two-Terminal and Four-Terminal Connections  
1-16  
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Preparation for Use  
Measurement Connections  
1
Alarm Outputs Connections  
The eight-terminal rear panel ALARM OUTPUTS connector (Figure 1-7) serves three  
functions: DC power, alarm outputs, and external trigger input. Each is described below.  
Terminal  
Function  
ALARM OUTPUTS  
+
0
1
2
3
TR  
Positive Input for DC Operation  
Negative Input for DC Operation  
Channel 0 Alarm Output  
Channel 1 Alarm Output  
Channel 2 Alarm Output  
Channel 3 Alarm Output  
External Trigger Input  
+ – 0 1 2 3 TR  
9-16 V  
DC PWR  
Ground Terminal  
op07f.eps  
Figure 1-7. ALARM OUTPUTS connector  
DC Power  
The instrument may be powered by a dc input between 9 volts and 16 volts allowing  
remote operation from various battery sources or dc power supplies. Connect the  
positive lead of the power supply to the + terminal and the negative lead to the -  
terminal. If the instrument is going to measure voltages greater than 50 volts dc or ac  
rms, also connect a ground wire between the rear panel ground lug and a suitable earth  
(safety) ground point (see Figure 1-4).  
Alarm Outputs  
Terminals 0, 1, 2, and 3 are used to signal alarm conditions for channels 0, 1, 2, and 3  
respectively using transistor-transistor-logic (TTL) voltage levels, referenced to the  
GROUND terminal. Logic high is >+2.0 to <+5.5V dc; a logic low is 0.0 to +0.8V dc. If  
a channel is not in alarm, the voltage output at a connector terminal is a logical high  
(nominal +5V dc); if a channel is in alarm, the output is a logical low (nominal +0.7V  
dc). Alarm outputs are set at the end of a scan interval. See Setting the Alarms in  
Chapter 2 for more information. If the instrument is operated over the RS-232 computer  
interface, the ALARM OUTPUTS can be assigned to I/O functions (assuming channels  
0, 1, 2, and 3 are not configured for alarms). See the ALARM_DO_LEVEL command,  
described in Chapter 4.  
External Trigger Input  
An external trigger input can serve the same function as the front panel SCAN key. A  
contact closure between TR and GROUND or a TTL logical low applied to TR  
(referenced to GROUND), will cause the instrument to scan. When the trigger input is  
removed, scanning will stop. Scanning is initiated on the falling edge of the trigger  
signal, which must be held logic low for at least 5 us and have been preceded by at least  
100 ms of logic high. Logic high is +2.0 to +7.0V dc; a logic low is -0.6 to +0.8V dc.  
See "Scan Triggering Options" in Chapter 2 for more information.  
Perform the following procedure to make connections to the ALARM OUTPUTS  
connector:  
1. Remove the connector from the rear panel.  
1-17  
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2635A  
Users Manual  
2. Loosen the wire clamp screw for the associated terminal.  
3. Feed the wire into the gap between the connector body and the wire clamp.  
4. Tighten the wire clamp screw.  
5. Insert the connector in the rear panel.  
Digital I/O Connections  
The ten-terminal rear panel DIGITAL I/O connector (Figure 1-8) serves two functions:  
Digital I/O and Totalizer input. Each is described below.  
Terminal  
Function  
DIGITAL I/O  
0
1
2
3
4
5
6
7
Σ
Input/Output Line 0  
Input/Output Line 1  
Input/Output Line 2  
Input/Output Line 3  
Input/Output Line 4  
Input/Output Line 5  
Input/Output Line 6  
Input/Output Line 7  
Totalizer Input  
0 1 2 3 4 5 6 7  
Σ
Ground Terminal  
op08f.eps  
Figure 1-8. DIGITAL I/O Connector  
Digital I/O  
Terminals 4 through 7 are used to signal alarm conditions for channels 4 through 20  
(default setting) using TTL voltage levels, referenced to the GROUND terminal. Logic  
high is >+2.0 to <+5.5V dc; a logic low is 0.0 to +0.8V dc. If a channel is not in alarm,  
the voltage output at a connector terminal is a logical high (nominal +5V dc); if a  
channel is in alarm, the output is a logical low (nominal +0.7V dc). Alarm outputs are  
changed at the end of each scan. See "Setting the Alarms" in Chapter 2 for more  
information. All alarm associations can be removed using computer commands, allowing  
the I/O terminals to be assigned to other functions as determined by computer  
commands. See the ALARM_ASSOC_CLR and related commands, described in Chapter  
4.  
Totalizer Input  
The totalizer is an internal counter that sums contact closures or voltage transitions.  
Connection is to the SUM terminal, referenced to GROUND. A contact closure and  
opening, or a voltage transition rising edge will cause the totalizer to advance by one  
count. The maximum count allowed is 65535 and the maximum count rate is 5 kHz.  
Voltages trigger on a low-to-high transition at a nominal threshold of +1.4 volts. A  
contact debounce feature is available when the instrument is operated through the RS-  
232 computer interface using the TOTAL_DBNC command, described in Chapter 4.  
Perform the following procedure to make connections to the DIGITAL I/O connector:  
1. Remove the connector from the rear panel.  
2. Loosen the wire clamp screw for the associated terminal.  
3. Feed the wire into the gap between the connector body and the wire clamp.  
1-18  
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Preparation for Use  
Controls and Indicators  
1
4. Tighten the wire clamp screw.  
5. Insert the connector in the rear panel.  
Controls and Indicators  
The front panel (Figure 1-1) provides a multipurpose display and a set of control keys.  
Each is described in the following paragraphs.  
Front Panel Controls  
The front panel keys (Figure 1-9) control all instrument operation: channel  
configuration, instrument configuration, measurement functions, and  
print/communications selections. Table 1-3 provides a summary of front panel key  
functions.  
Front Panel Indicators  
The front panel indicators are divided into three portions: Primary Display (Figure 1-10),  
Secondary Display (Figure 1-11), and Display Annunciators (Figure 1-12). Table 1-4  
describes each annunciator function.  
INTVL  
FILES  
REVIEW  
FUNC  
ALRM  
SCAN  
CLOCK  
MODE  
CLEAR  
SINGLE  
RATE  
ENTER  
+
CANCL  
Mx B  
MON  
SHIFT  
LIST  
TOTAL  
LOCAL  
COMM  
ZERO  
TRIGS  
BUSY BATT  
op09f.eps  
Figure 1-9. Front Panel Keys  
FUNC  
F
SET  
Mx+B  
MAX REM SCAN  
MIN AUTO MON  
REVIEW  
LAST  
ALARM  
°C °F RO  
PRN CH  
EXT TR  
OFF  
CAL  
mV AC DC  
LIMIT  
1 2  
HI  
LO  
x1Mk  
Hz  
op10f.eps  
Figure 1-10. Primary Display  
1-19  
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2635A  
Users Manual  
FUNC  
F
SET  
Mx+B  
MAX REM SCAN  
MIN AUTO MON  
REVIEW  
LAST  
ALARM  
°C °F RO  
PRN CH  
EXT TR  
OFF  
CAL  
mV AC DC LIMIT HI  
x1Mk Hz  
1 2 LO  
op11f.eps  
Figure 1-11. Secondary Display  
FUNC  
F
SET  
Mx+B  
MAX REM SCAN  
MIN AUTO MON  
REVIEW  
LAST  
ALARM  
°C °F RO  
PRN CH  
EXT TR  
OFF  
CAL  
mV AC DC LIMIT HI  
x1Mk Hz  
1 2 LO  
op12f.eps  
Figure 1-12. Annunciator Display  
1-20  
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Preparation for Use  
Controls and Indicators  
1
Table 1-3. Front Panel Keys Description  
Description  
Key  
F
A
B
C
Calls up the menu to set the function for the channel  
Calls up the menu to set alarm limits Sand Tfor the channel.  
Calls up the menu to set scaling on the channel.  
Used to exit any setup menu and return to Inactive Mode, without saving  
settings you’ve selected thus far. Exceptions exist under the following two  
conditions  
If you cancel out of the alarm menu part way through defining alarm limit T, any  
just-made entries for alarm limit Swill still take effect.  
If you cancel out of the Mx+B menu part way through defining the B value, any  
just-made entries for the M value will still take effect.  
This key also provides a handy way to remove the Totalizer value or Review  
data from the display.  
G D  
J H  
Used to change the channel number and to step through choices in any of the  
setup menus. These arrow keys have an automatic repeat action when held  
down for more than 1 second.  
Used to step through choices in several of the setup menus. These arrow keys  
have an automatic repeat action when held down for more than 1 second.  
E
I
Used to accept a selection just made in any setup menu.  
Allows you to change the scan interval. Scanning becomes continuous when  
the interval is set to 0:00:00.  
P
Accesses menus related to memory card operation, including status, directory,  
and manipulation of all SEtxx and dAtxx files.  
N
K
Calls up the Review array of MIN, MAX and LAST values to the display.  
Accesses secondary functions under various keys, as described below. When  
this key is pressed, "SHIFt" appears on the right display, but automatically  
disappears if you have not made a selection within 5 seconds or press C.  
L
Prints out the Last values of the Review array or contents of the memory card  
directory via the RS-232 computer interface.  
O
Q
Calls up the present Totalizer count to the display.  
Turns the Scan function on or off.  
Triggers a single scan when the instrument is under remote control without  
lockout (REMS).  
M
Turns the Monitor function on or off  
RATE K J  
Allows you to change the scanning speed: “Slo” for highest accuracy, or “FASt”  
for highest throughput  
CLOCK K I  
MODE K P  
Allows you to set the internal day/date clock  
Allows you to select the destination and conditions for which scan  
measurements will be automatically printed or logged.  
1-21  
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2635A  
Users Manual  
Table 1-3. Front Panel Keys Description (cont.)  
Description  
Key  
CLEAR  
K N  
This key sequence clears the entire contents of the Review array. Review data  
must be presently shown on the display to clear the array.  
LOCAL K  
When under remote control without lockout (REMS), this returns control to the  
front panel.  
COMM K L  
Allows you to set up the computer interface port.  
ZERO  
K O  
While the Totalizer count is displayed, resets the Totalizer to 0.  
SINGLE K Q  
Forces an immediate scan of all defined channels. If a scan is presently in  
progress, this new request is ignored. Once begun, the full scan is completed.  
Configuration changes are not allowed while a scan is in progress.  
Table 1-4. Annunciator Descriptions  
Description  
Annunciator  
MON  
Indicates that the Monitor function is enabled.  
SCAN  
Indicates that the Scan function is enabled. Scanning can be enabled as a single scan  
(KQ), with a scan interval, with an alarm-trigger or with an external trigger.  
CH  
Indicates that the channel number is displayed immediately above, in the right display.  
Lit when the instrument is in Configuration Mode.  
SET  
Mx+B  
Lit while Mx+B scaling is being defined and when a measurement on the display has  
been scaled with an M value other than 1 and/or a B value other than 0 has been  
defined for this channel.  
FUNC  
Lit when a measurement function is being defined for this channel.  
ALARM  
Lit when alarm values are being defined for this channel or when an alarm limit has  
been exceeded while measuring.  
v
Indicates that the measurement function is volts for this channel (used with the AC or  
DC annunciator).  
DC  
AC  
e
Indicates that the measurement function is dc voltage for this channel.  
Indicates that the measurement function is ac voltage for this channel.  
Indicates that the measurement function is resistance for this channel.  
Indicates that the measurement function is frequency for this channel.  
Hz  
°C  
Indicates that the measurement function is temperature for this channel and that the  
degree unit is Celsius.  
°F  
m
x1  
k
Indicates that the measurement function is temperature for this channel and that the  
degree unit is Fahrenheit.  
(milli) a multiplier for the displayed value, e.g., mV for millivolts. Also used when defining  
alarm and Mx+B values.  
(times 1) a multiplier for the displayed value. Used when defining alarm and Mx+B  
values.  
(kilo) a multiplier for the displayed value, e.g., kHz for kilohertz. Also used when defining  
alarm and Mx+B values.  
1-22  
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Preparation for Use  
Controls and Indicators  
1
Table 1-4. Annunciator Descriptions (cont)  
Description  
Annunciator  
M
(mega) a multiplier for the displayed value, e.g., M½ for megohms. Also used when  
defining alarm and Mx+B values.  
R0  
Lit when the ice point resistance is being defined for RTD measurements on the  
displayed channel.  
OFF  
Indicates there is no measurement function defined for the displayed channel; OFF  
channels are skipped over when scanning. OFF is also used when defining an alarm  
value to indicate that the alarm limit is to be ignored.  
AUTO  
LIMIT  
Indicates that autoranging is enabled for the displayed channel.  
Used with the [1] and [2] annunciators when you are setting an alarm limit value. Also lit  
when displaying a measurement value (LAST, Monitor) which has exceeded an alarm  
limit.  
1
Lit when alarm limit 1 is being defined. Also lit when displaying a measurement value  
(LAST, Monitor) which has exceeded alarm limit 1.  
2
Lit when alarm limit 2 is being defined. Also lit when displaying a measurement value  
(LAST, Monitor) which has exceeded alarm limit 2.  
HI, LO  
REVIEW  
MIN, MAX  
LAST  
PRN  
Identifies alarm limit sensing (high or low) during channel configuration. At other times,  
identifies an alarm condition.  
Indicates that review data is being displayed (used in conjunction with the MIN, MAX,  
and LAST annunciators).  
Indicates that the displayed value is the minimum (maximum) value measured on this  
channel.  
Indicates that the displayed value is the most recent scan measurement taken on this  
channel.  
Indicates that the autoprint function is enabled (to send readings to a printer or PC) or  
the memory storage function is on (to store readings in a memory card).  
EXT  
TR  
Indicates that external triggering (on the rear panel) is enabled.  
Indicates that internal triggering (from the monitor alarm) is enabled. Also used with EXT  
when external triggering is enabled.  
REM  
Indicates that the instrument is under the control of the RS-232 computer interface  
(bright) or a front panel lockout option has been enabled (dim).  
CAL  
F
Indicates that the instrument's internal calibration constants have been corrupted.  
(Not Used)  
1-23  
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2635A  
Users Manual  
1-24  
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Chapter 2  
Front Panel Operations  
Title  
Page  
Summary of Front Panel Operations................................................................. 2-5  
Configuring the Instrument for Operation......................................................... 2-6  
Turning the Power on.................................................................................... 2-6  
Selecting a Channel....................................................................................... 2-8  
Configuring a Measurement Channel................................................................ 2-8  
Configuring a Channel to Measure DC Volts............................................... 2-9  
Configuring a Channel to Measure AC Volts............................................... 2-10  
Configuring a Channel to Measure Resistance............................................. 2-11  
Configuring a Channel to Measure Frequency ............................................. 2-12  
Configuring a Channel to Measure Temperature.......................................... 2-13  
Thermocouples ......................................................................................... 2-13  
Resistance-Temperature Detectors........................................................... 2-13  
Thermocouple Restrictions:...................................................................... 2-13  
Resistance Temperature Detectors Restrictions:...................................... 2-13  
Configuring a Channel Off ........................................................................... 2-16  
Setting Operating Conditions............................................................................ 2-16  
Setting the Scan Interval ............................................................................... 2-17  
Setting the Measurement Rate ...................................................................... 2-18  
Setting the Alarms......................................................................................... 2-18  
Alarm Indications While Scanning........................................................... 2-18  
Alarm Indications While Monitoring ....................................................... 2-19  
Alarm Indications While Reviewing ........................................................ 2-19  
Clearing Alarm Parameters from a Channel............................................. 2-19  
Alarm Outputs for Channel 0 to 3 Using the Alarm Outputs Connector . 2-19  
Alarm Outputs for Channels 4 to 20 Using the Digital I/O Connector .... 2-19  
Alarms and Autoprinting.......................................................................... 2-20  
Alarms and Monitor-Alarm Triggering.................................................... 2-20  
Alarms and Mx+B Scaling ....................................................................... 2-20  
Setting the Mx+B Scaling............................................................................. 2-23  
Examples................................................................................................... 2-23  
Restrictions ............................................................................................... 2-23  
Clearing Mx+B Scaling from a Channel .................................................. 2-23  
Operating Modes ............................................................................................... 2-26  
Using the Scan Mode .................................................................................... 2-26  
Memory Card as a Data Destination......................................................... 2-26  
2-1  
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2635A  
Users Manual  
Memory Card Formatting......................................................................... 2-26  
Memory Card Capacity............................................................................. 2-26  
Memory Card Files................................................................................... 2-26  
Memory Card Exchange During Scanning............................................... 2-26  
Memory Card Data Extraction.................................................................. 2-27  
Memory Card Error Messages ...................................................................... 2-28  
Using the Monitor Mode............................................................................... 2-29  
Using the Review Mode................................................................................ 2-30  
Additional Features ........................................................................................... 2-31  
Scan Triggering Options ............................................................................... 2-31  
External Trigger........................................................................................ 2-31  
Monitor-Alarm Trigger............................................................................. 2-31  
Triggering Options and Memory Card Operation .................................... 2-31  
Totalizer Operation ....................................................................................... 2-32  
Digital Input/output Lines............................................................................. 2-33  
Setting Date and Time................................................................................... 2-34  
Reading Instrument Software Versions ........................................................ 2-35  
Returning to the Local Mode ........................................................................ 2-35  
Front Panel Key Lockout Options ................................................................ 2-36  
Instrument Interfaces......................................................................................... 2-36  
Memory Card Interface................................................................................. 2-36  
RS-232 Computer Interface .......................................................................... 2-37  
Using the RS-232 Computer Interface With a Printer .................................. 2-37  
Using the RS-232 Computer Interface With a Modem................................. 2-37  
2-2  
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Front Panel Operations  
Summary of Front Panel Operations  
2
2-3  
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2635A  
Users Manual  
HYDRA DATA BUCKET  
REVIEW  
LAST  
mA  
mVDCAC  
CH  
k
Hz  
COM  
V
INTVL  
FILES  
MODE  
REVIEW  
CLEAR  
SCAN  
FUNC  
Mx+B  
ALRM  
300V  
MAX  
CLOCK  
RATE  
SINGLE  
MON  
CANCEL  
ENTER  
SHIFT  
LIST  
TOTAL  
ZERO  
LOCAL  
COMM  
TRIGS  
BUSY BATT  
op92f.eps  
2-4  
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Front Panel Operations  
Summary of Front Panel Operations  
2
Summary of Front Panel Operations  
Descriptions of all equipment operations start at the front panel and proceed through the  
following topics, which appear in the following sequence:  
Preparing for Operation  
Configuring a Measurement Channel  
Setting Operating Conditions  
Operating Modes  
Additional Features  
Instrument Interfaces  
This chapter applies exclusively to instrument applications that use only the front panel  
controls and annunciators. Other chapters apply specifically to applications that use the  
memory card feature or interface with a computer, printer, or modem. It is assumed that  
the user has understood the information in Chapter 1, "Preparation for Use," including  
such topics as setting up the instrument and making measurement connections. Perform  
the Ten-Minute Tour at the front of this manual for a quick overview of instrument  
operation.  
All the procedures in this chapter use control/annunciator diagrams that provide the  
control sequences and expected indicators for each operation. A summary of how to use  
the control/annunciator diagrams is shown in Figure 2-1.  
Press then release the  
The shaded portion above  
a menu indicates a front  
panel display for that  
menu. In this example,  
the menu is called SET  
FUNC.  
SET FUNC  
FUNC  
front panel key shown. In  
this example, press the  
FUNC key  
OFF  
°F  
Hz  
VAC  
Use the up/down arrow  
keys to select an item from  
the displayed menu.  
A solid pointer means the  
menu selection is required.  
In this example, °F must  
be selected.  
V DC  
When the menu item  
selected with the up/down  
arrow keys is correct,  
press the ENTER key.  
ENTER  
SET FUNC  
A dotted arrow means the  
menu selection is typical  
and the user must choose  
the item that meets the  
instrument application. In  
J
K
E
T
N
R
S
b
When there are multiple  
selections, the procedure  
will continue.  
this example,  
a
typical  
choice is thermocouple T.  
ENTER  
C
Pt  
A dotted pointer indicates  
a typical menu selection,  
while  
indicates  
selection.  
a
solid pointer  
required  
A procedure that includes  
an audible "beep" will use  
a beep symbol as shown.  
Typical  
Required  
= "Beep"  
a
op13f.eps  
Figure 2-1. How to use the Control/Annunciator Diagrams  
2-5  
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2635A  
Users Manual  
Configuring the Instrument for Operation  
To prepare the equipment for front panel operations, perform the two following  
procedures:  
Turning the Power On (Figure 2-2)  
Selecting a Channel (Figure 2-3)  
Turning the Power on  
There are four power-on options. Figure 2-2 describes the control sequences for each  
option.  
Each power-on sequence includes a four-second selftest routine that lights the front  
panel display. If the selftest fails, the instrument will beep and display ERROR plus an  
alphanumeric error code character (see Table 2-2). If there is more than one error, each  
is displayed in sequence at two-second intervals. Refer to the maintenance information  
in Chapter 7 for guidance on what to do when an error is detected.  
Simple Power-On. Press the POWER switch.  
POWER  
(Selftest)  
Error  
After selftest, the display clears and the  
instrument resumes whatever operation was in  
effect when power was last removed.  
Configuration-Reset Power-On. Hold down the  
CANCL key and press the POWER switch. Hold  
the CANCL key until the instrument completes  
selftest and "beeps" in acknowledgement. All  
channel configuration data is erased and the  
operating parameters are set to default settings  
(see Table 2-1). The temperature scale and  
communication settings are not affected.  
(Selftest)  
Error  
CANCL  
+
POWER  
Display-Hold Power-On. Hold down the SHIFT  
key and press the POWER switch. Hold the  
SHIFT key until the instrument completes the  
selftest routine and "beeps" in acknowledgement.  
The front panel display will remain lit until any key  
is pressed.  
(Selftest)  
Error  
SHIFT  
+
POWER  
Temperature-Toggle Power-On. Hold down the  
Mx+B key and press the POWER switch. Hold  
the Mx+B key until the instrument completes  
selftest, "beeps" in acknowledgement, displaying  
either °F or °C. To select the other temperature  
scale, remove power and repeat the procedure.  
(Selftest)  
Error  
Mx+B  
+
POWER  
op14f.eps  
Figure 2-2. Turning the Power On  
2-6  
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Front Panel Operations  
Configuring the Instrument for Operation  
2
Table 2-1. Configuration Reset (Default) Settings  
Parameter Default Setting  
Channels 0 to 20  
Off  
Measurement Rate  
Mx+B Scaling  
Slow  
1x+0 (all channels)  
Scan Interval  
0:00:00 (continuous)  
Cleared (all channels)  
Set High (non-alarm)  
0/Debounce Disabled  
None  
Review Values  
Digital I/O Lines  
Totalizer  
Destination  
RTD R0  
100.00 (all channels)  
Enabled  
Open Thermocouple Detection (OTC)  
Alarm Limits  
Off/Limit Values=0  
Alarm Assignments  
Channels 0 to 3, to ALARM OUTPUTS 0 to 3.  
Channels 4 to 20, to DIGITAL I/O as below:  
DIGITAL I/O LINE  
4
5
6
7
Alarm Channel  
(ORed to drive  
each I/O line)  
4
8
5
9
6
7
10 11  
12 13 14 15  
16 17 18 19  
20  
Table 2-2. Selftest Error Codes  
Code  
Description  
1
2
3
5
6
7
8
9
A
b
C
d
Boot ROM Checksum Error  
Instrument ROM Checksum Error  
Internal RAM Test Failed  
Display Power-Up Test Failed  
Display Not Responding  
Instrument Configuration Corrupted  
Instrument Not Calibrated  
A-to-D Converter Not Responding  
A-to-D Converter ROM Test Failed  
A-to-D Converter RAM Test Failed  
A-to-D Converter Selftest Failure  
Memory Card Interface Not Installed  
2-7  
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2635A  
Users Manual  
Selecting a Channel  
There are 21 channels, 0 to 20. A channel is selected for configuration or configuration  
verification when the instrument is in the inactive mode. An active channel is selected  
for monitoring when the instrument is in the Monitor Mode (see Figure 2-17) or Review  
Mode (see Figure 2-18). Perform the procedure in Figure 2-3 to select a channel.  
Restrictions  
Locked Out Channels. Any channel 1 to 10 (n) assigned to four-terminal (4T)  
measurements locks out a corresponding channel a decade higher (n+10). For example,  
use of channel 3 for 4T measurements locks out channel 13, which can be selected, but  
not configured.  
Restricted Channels. Channel 0 (front panel terminals) does not support thermocouple  
measurements or four-terminal measurements.  
Selecting a Channel. Press the up/down arrow  
keys until the CH (Channel) display shows the  
CH  
20  
19  
18  
17  
16  
15  
14  
13  
12  
11  
10  
9
desired channel, for example, CH 12 (Channel  
12).  
8
7
6
5
4
3
2
Typical  
1
0
Required  
op15f.eps  
Figure 2-3. Selecting a Channel  
Configuring a Measurement Channel  
The following paragraphs provide configuration procedures for DC Volts, AC Volts,  
Resistance, Frequency, Temperature, and describe how to turn a channel Off:  
Configuring a Channel to Measure DC Volts (Figure 2-4)  
Configuring a Channel to Measure AC Volts (Figure 2-5)  
Configuring a Channel to Measure Resistance (Figure 2-6)  
Configuring a Channel to Measure Frequency (Figure 2-7)  
2-8  
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Front Panel Operations  
Configuring a Measurement Channel  
2
Configuring a Channel to Measure Temperature (Thermocouples) (Figure 2-8)  
Configuring a Channel to Measure Temperature (RTDs) (Figure 2-9)  
Configuring a Channel Off (Figure 2-10)  
The instrument is protected from channel configuration errors. For example, accidentally  
applying 300V ac to a channel configured for resistance will not damage the instrument.  
Configuring a Channel to Measure DC Volts  
Perform the procedure in Figure 2-4 to configure a channel for measuring dc volts. In  
preparation, the instrument must be in the inactive mode (not scanning or monitoring)  
and the desired channel must be selected (see Figure 2-3). To exit at any time (changes  
not saved), press the C key.  
Restrictions  
Maximum Input. The maximum voltage inputs are 300V dc for channels 0, 1, 11, and  
150V dc for channels 2 to 10, and 12 to 20.  
90.000 mV Range. Not used in Auto (autoranging).  
Selecting the DC Volts Mode. Press the FUNC  
SET FUNC  
FUNC  
key to access the SET FUNC (Set Function)  
menu. Press the up/down arrow keys until V DC  
(volts dc) is displayed, then press the ENTER  
key.  
OFF  
°F [°C]*  
Hz  
VAC  
V DC  
ENTER  
Selecting the Measurement Scale. Select a  
fixed scale or Auto (autoranging). A fixed scale  
SET FUNC  
Auto  
indicates an upper measurement limit.  
For  
300.00 V **  
150.00 V ***  
30.000 V  
3.0000 V  
300.00 mV  
90.000 mV  
example, the 30.000 V scale measures 30 volts  
or less. Measurements beyond the scale limit will  
cause an OL (overload) display. The x1 (1.0)  
multiplier indicates a reading in volts dc; the m  
multiplier (0.001) indicates a reading in millivolts  
dc. A 900.00 mV range is available by computer  
interface and may appear in the display if this  
was previously selected.  
ENTER  
Typical  
Required  
In Auto (autoranging), the instrument chooses the  
scale for the best measurement resolution.  
When the scales are changed, the scan is  
momentarily slowed.  
* Depends on temperature scale.  
** Channels 0, 1, and 11.  
*** Channels 2 to 10, and 12 to 20.  
op16f.eps  
Figure 2-4. Configuring a Channel to Measure DC Volts  
2-9  
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2635A  
Users Manual  
Configuring a Channel to Measure AC Volts  
Perform the procedure in Figure 2-5 to configure a channel for measuring ac volts. In  
preparation, the instrument must be in the inactive mode (not scanning or monitoring)  
and the desired channel must be selected (see Figure 2-3). To exit at any time (changes  
not saved), press the C key.  
Restrictions  
Maximum Input. The maximum voltage inputs are 300V ac (rms) for channels 0, 1, 11,  
and 150V ac (rms) for channels 2 to 10, and 12 to 20.  
Frequency. The frequency range for maximum voltage inputs is 20 Hz to 100 Hz. Refer  
to Appendix A for derated voltage inputs for frequencies between 100 Hz and 100 kHz.  
Selecting the AC Volts Mode. Press the FUNC  
SET FUNC  
FUNC  
key to access the SET FUNC (Set Function)  
menu. Press the up/down arrow keys until VAC  
(Volts AC) is displayed, then press the ENTER  
key.  
OFF  
°F [°C]*  
Hz  
VAC  
V DC  
ENTER  
Selecting the Measurement Scale. Select a  
fixed scale or Auto (autoranging). A fixed scale  
SET FUNC  
Auto  
indicates an upper measurement limit.  
For  
300.00 V **  
150.00 V ***  
30.000 V  
3.0000 V  
300.00 mV  
example, the 30.000 V scale measures 30 volts  
or less. Measurements beyond the scale limit will  
cause an OL (overload) display. The x1 (unity or  
x 1) multiplier indicates a reading in volts ac; the  
m (milli or x .001) multiplier indicates a reading in  
millivolts ac.  
ENTER  
* Depends on  
temperature scale.  
In Auto (autoranging), the instrument chooses the  
scale for the best measurement resolution.  
When the scales are changed, the scan is  
momentarily slowed.  
** Channels 0, 1,  
and 11.  
Typical  
Required  
*** Channels 2 to  
10, and 12 to 20.  
op17f.eps  
Figure 2-5. Configuring a Channel to Measure AC Volts  
2-10  
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Front Panel Operations  
Configuring a Measurement Channel  
2
Configuring a Channel to Measure Resistance  
Perform the procedure in Figure 2-6 to configure a channel for measuring resistance. In  
preparation, the instrument must be in the inactive mode (not scanning or monitoring)  
and the desired channel must be selected (see Figure 2-3). To exit at any time (changes  
not saved), press the C key.  
The resistance to be measured can be connected using one channel (two-terminal  
connection) or two channels (four-terminal connection). The four-terminal connection  
provides increased measurement precision. The two channels used in a four-terminal  
connection are a decade apart (n and n+10), for example, channel 3 (n) and 13 (n+10).  
Only the lower channel is configured.  
Restrictions  
Four-Terminal Channels. Four-Terminal configurations are limited to channels 1 to 10  
(n). The channel a decade higher (n + 10) is automatically reserved for use.  
Selecting the Resistance Mode. Press the  
SET FUNC  
FUNC  
FUNC key to access the SET FUNC (Set  
Function) menu. Press the up/down arrow keys  
until (ohms) is displayed, then press the  
ENTER key.  
OFF  
°F [°C]*  
Hz  
VAC  
V DC  
ENTER  
Selecting the Measurement Scale. Select a  
fixed scale or Auto (autoranging). A fixed scale  
indicates an upper measurement limit. For  
example, the 30.000 kscale measures 30 kΩ  
ohms or less. Measurements beyond the scale  
limit will cause an OL (overload) display. The x1  
(unity or x 1) multiplier indicates a reading in  
ohms; the k (kilo or x 1,000) multiplier indicates a  
reading in kilohms; the M (mega or x 1,000,000)  
multiplier indicates a reading in megohms.  
SET FUNC  
Auto  
10.000 M  
3.0000 M  
300.00 k  
30.000 k  
3.0000 k  
300.00  
ENTER  
* Depends on  
temperature scale.  
In Auto (autoranging), the instrument chooses the  
scale for the best measurement resolution.  
When scales are changed, the scan is  
momentarily slowed.  
** Channels 1 to 10.  
Selecting the Terminal Mode. Select the two-  
terminal (2T) or four-terminal (4T) mode. 4T  
automatically clears configuration data from the  
channel a decade higher (n+10). For example,  
SET FUNC  
2T  
4T**  
selecting channel  
automatically clear channel 13 of all configuration  
data and lock it out from further use.  
3
for 4T operation will  
Typical  
Required  
ENTER  
op18f.eps  
Figure 2-6. Configuring a Channel to Measure Resistance  
2-11  
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2635A  
Users Manual  
Configuring a Channel to Measure Frequency  
Perform the procedure in Figure 2-7 to configure a channel for measuring frequency. In  
preparation, the instrument must be in the inactive mode (not scanning or monitoring)  
and the desired channel must be selected (see Figure 2-3). To exit at any time (changes  
not saved), press the C key.  
Restrictions  
Frequency Range. The frequency range for measurements is 15 Hz minimum to greater  
than 1 MHz.  
Maximum Input. The maximum voltage inputs are 300V ac (rms) for channels 0, 1, 11,  
and 150V ac (rms) for channels 2 to 10, and 12 to 20. The frequency range for maximum  
voltage inputs is 15 Hz to 100 Hz. Refer to Appendix A for derated voltage inputs for  
frequencies between 100 Hz and 100 kHz.  
Selecting the Frequency Mode. Press the  
SET FUNC  
FUNC  
FUNC key to access the SET FUNC (Set  
Function) menu. Press the up/down arrow keys  
until Hz (Hertz) is displayed, then press the  
ENTER key.  
OFF  
°F [°C]*  
Hz  
VAC  
V DC  
ENTER  
Selecting the Measurement Scale. Select a  
fixed scale or Auto (autoranging). A fixed scale  
SET FUNC  
Auto  
indicates an upper measurement limit.  
For  
1.0000 MHz  
900.00 kHz  
90.000 kHz  
9.0000 kHz  
900.00 Hz  
example, the 90.000 kHz scale measures 90 kHz  
or less. Measurements beyond the scale limit will  
cause an OL (overload) display. The x1 (unity or  
x 1) multiplier indicates a reading in Hz; the k  
(kilo or x 1,000) multiplier indicates a reading in  
kilohertz; the M (mega or x 1,000,000) multiplier  
indicates a reading in megahertz.  
ENTER  
Typical  
In Auto (autoranging), the instrument chooses the  
scale for the best measurement resolution.  
There are no scanning delays with frequency  
autoranging.  
Required  
* Depends on  
temperature scale.  
op19f.eps  
Figure 2-7. Configuring a Channel to Measure Frequency  
2-12  
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Front Panel Operations  
Configuring a Measurement Channel  
2
Configuring a Channel to Measure Temperature  
Perform the procedure in Figure 2-8 to configure a channel for measuring temperature  
with thermocouples, or Figure 2-9 to measure temperature with resistance-temperature  
detectors (RTDs). In preparation, the instrument must be in the inactive mode (not  
scanning or monitoring) and the desired channel must be selected (see Figure 2-3). To  
exit at any time (changes not saved), press the C key. The temperature scale, ºC or ºF,  
is set by the Temperature-Toggle Power-On procedure (see Figure 2-2). When under  
computer control, an open thermocouple default can be set by the TEMP_CONFIG  
command.  
Thermocouples  
Thermocouples are formed by joining two wires of dissimilar metals, which produce a  
voltage proportional to the temperature of the wire junction. The instrument conditions  
this voltage into temperature measurements. Voltage conditioning includes  
compensation for the type of thermocouple used and measurement-process  
compensation that uses a reference temperature sensor built into the Input Module  
(channels 1 to 20). The front panel terminals (channel 0) cannot be used for  
thermocouples. The instrument supports nine standard thermocouples, each identified  
with an American National Standards Institute (ANSI) alpha character (except [ ]): J,  
[C], B, S, R, N, T, E, or K. A thermocouple type is selected as part of the channel  
configuration. Table 2-3 summarizes the ranges and characteristics of the supported  
thermocouples. The instrument displays "otc" when an open thermocouple is detected  
(as selected with the TEMP_CONFIG command - see Chapter 4). A type "T"  
thermocouple is supplied with the instrument.  
Resistance-Temperature Detectors  
Resistance-Temperature Detectors (RTDs) are formed from coils or strips of metal,  
usually platinum, the resistance of which varies with temperature. The instrument  
conditions this resistance into temperature measurements. The instrument supports any  
platinum RTD that is calibrated to the IEC 751 Standard (a=0.00385 ohms/ohm/ºC).  
RTDs are characterized by their resistance at 0 ºC, which is called the "ice point" or R0.  
The most common R0 is 100 ohms. The instrument supports any IEC 751 Platinum RTD  
with an R0 from 000.00 to 999.99, with a default of R0=100.00. Since RTDs are  
resistance devices, they can be connected to the instrument using one channel (two-  
terminal connection) or two channels (four-terminal connection). A four-channel  
configuration provides increased measurement precision. Some RTDs can be purchased  
in a four-terminal configuration, facilitating a four-terminal connection. The two  
channels used in a four-terminal connection are a decade apart (n and n+10), for  
example, channel 3 (n) and 13 (n+10). Only the lower channel is configured.  
Thermocouple Restrictions:  
Channel 0. Thermocouple measurements cannot use channel 0.  
Open Thermocouple. The instrument displays OTC when an open thermocouple is  
detected and ignores the channel while scanning.  
Resistance Temperature Detectors Restrictions:  
Four-Terminal Channels. Four-Terminal configurations are limited to channels 1 to 10  
(n). The channel a decade higher (n + 10) is automatically reserved for use.  
2-13  
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2635A  
Users Manual  
Table 2-3. Thermocouple Ranges  
Positive Lead  
Negative Lead  
Material  
Constantan  
Usable  
(H) Color  
Range (°C)  
Type  
Material  
ANSI*  
IEC**  
J
Iron  
White  
White  
Gray  
Black  
-200 to 760  
0 to 2316  
C***  
b
Tungsten (5% Rhenium)  
Platinum (30% Rhodium)  
Platinum  
Tungsten (26% Rhenium)  
Platinum (6% Rhodium)  
Platinum (10% Rhodium)  
0 to 1820  
S
Black  
Orang  
-50 to 1768  
e
R
N
Platinum  
Black  
Orang  
e
Platinum (13% Rhodium)  
NISIL  
-50 to 1768  
NICROSIL  
Orang  
e
-270 to 1300  
T
E
K
Copper  
Chromel  
Chromel  
Blue  
Brown  
Violet  
Green  
Constantan  
Constantan  
Alumel  
-270 to 400  
-270 to 1000  
-270 to 1372  
Purple  
Yellow  
* American National Standards Institute (ANSI) device negative lead (L) is always red.  
** International Electrotechnical Commission (IEC) device negative lead (L) is always white.  
*** Not an ANSI designation but a Hoskins Engineering Company designation.  
Selecting the Temperature Mode. Press the  
FUNC key to access the SET FUNC (Set  
Function) menu. Press the up/down arrow keys  
until °C (Centigrade) or °F (Fahrenheit) is  
displayed, then press the ENTER key. (If the  
opposite temperature scale is desired, refer to  
Figure 2-2.)  
SET FUNC  
FUNC  
ENTER  
ENTER  
OFF  
°F [°C]*  
Hz  
VAC  
V DC  
Selecting the Type of Thermocouple. Select  
the desired type of thermocouple from the menu,  
for example, T, then press ENTER. The "Pt"  
(Platinum) setting is used for RTDs only (See  
Figure 2-9).  
SET FUNC  
J
K
E
T
N
R
S
* Depends on  
temperature scale.  
b
** Only Pt can be  
selected for Channel 0.  
C
Pt**  
Typical  
Required  
op20f.eps  
Figure 2-8. Configuring a Channel to Measure Temperature (Thermocouples)  
2-14  
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Front Panel Operations  
Configuring a Measurement Channel  
2
Selecting the Temperature Mode. Press the  
SET FUNC  
FUNC  
FUNC key to access the SET FUNC (Set  
Function) menu. Press the up/down arrow keys  
until °C (Centigrade) or °F (Fahrenheit) is  
displayed, then press the ENTER key. (If the  
opposite temperature scale is desired, refer to  
Figure 2-2.)  
OFF  
°F [°C]*  
Hz  
VAC  
V DC  
ENTER  
Selecting the RTD Mode. Select Pt (Platinum),  
then press the ENTER key.  
SET FUNC  
J
K
E
T
N
R
S
ENTER  
b
C
Pt**  
Selecting the Terminal Mode. Select the two-  
terminal (2T) or four-terminal (4T) mode. 4T  
automatically clears configuration data from the  
channel a decade higher (n+10). For example,  
SET FUNC  
2T  
4T**  
selecting channel  
3
for 4T operation will  
automatically clear channel 13 of all configuration  
data and lock it out from further use.  
ENTER  
Selecting the "Ice Point" (R0).  
Use the  
Ro  
up/down and left/right arrow keys to enter the  
desired number, then press the ENTER key. The  
default and most common setting is 100.00  
(R0=100.00 ohms at 0 °C [32 °F]).  
0 0 0 . 0 0  
- to -  
9 9 9 . 9 9  
* Depends on  
Typical  
temperature scale.  
ENTER  
Required  
** Channels 1 to 10.  
op21f.eps  
Figure 2-9. Configuring a Channel to Measure Temperature (RTDs)  
2-15  
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2635A  
Users Manual  
Configuring a Channel Off  
Perform the procedure in Figure 2-10 to configure a channel for off (no measurement).  
In preparation, the instrument must be in the inactive mode (not scanning or monitoring)  
and the desired channel must be selected (see Figure 2-3). To exit at any time (changes  
not saved), press the C key. When a channel is OFF, it cannot be scanned or  
monitored. When a channel function is changed, alarm limits and scaling (Mx+B) for  
that channel are changed to their default conditions.  
Selecting the OFF Mode. Press the FUNC key  
SET FUNC  
FUNC  
to access the SET FUNC (Set Function) menu.  
Press the up/down arrow keys until OFF is  
displayed, then press the ENTER key.  
OFF  
°F [°C]*  
Hz  
VAC  
V DC  
* Depends on  
temperature scale.  
ENTER  
Typical  
Required  
op22f.eps  
Figure 2-10. Configuring a Channel Off  
Setting Operating Conditions  
After the channels are configured for the desired measurement parameter, set the  
following operating conditions to support the intended instrument function:  
Setting the Scan Interval [Default - 0:00:00 (Continuous)] (Figure 2-11)  
Setting the Measurement Rate [Default - Slow] (Figure 2-12)  
Setting the Alarms [Default - Alarms off] (Figures 2-13)  
Setting the Mx+B Scaling [Default - 1x+0 (no scaling)] (Figure 2-14)  
The instrument default settings for each of the above are shown.  
2-16  
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Front Panel Operations  
Setting Operating Conditions  
2
Setting the Scan Interval  
Perform the procedure in Figure 2-11 to set the time between starts of measurement  
scans. In preparation, the instrument must be in the inactive mode (not scanning or  
monitoring). To exit at any time (changes not saved), press the C key. The scanning  
interval format is HOURS:MINUTES:SECONDS. The minimum is 0:00:00 (continuous  
scanning [default]); the maximum is 9:99:99 (9 hours, 99 minutes, 99 seconds). The scan  
interval is divided into two portions: the measurement interval when measurements are  
actually taken, and the time-out interval that completes the overall scan duration. For  
example, if 10 channels can be measured in 8 seconds, and the scanning interval is set  
for 30 seconds, the first 8 seconds are used for measurement, while the remaining 22  
seconds are used to time out. If the scanning interval is set to less than the measurement  
rate, the effect is continuous scanning. For example, if 10 channels can be measured in 8  
seconds and the scanning interval is set for 5 seconds, scanning is continuous. To speed  
up the measurement rate, refer to Figure 2-12.  
INTVL  
Setting the Scan Interval. Press the INTVL  
(Interval) key to access the scan time menu. The  
SET  
0: 0 0 : 0 0  
- to -  
9: 9 9 : 9 9  
format is HOURS:MINUTES:SECONDS. Press  
the up/down and left/right arrow keys to select  
and configure each column in the menu. For  
example, a scan interval of 1 hour, 25 minutes,  
and 33 seconds would be formatted as 1:25:33.  
The column being configured will have a bright  
display. When the display shows the desired  
interval, press the ENTER key.  
Typical  
ENTER  
Required  
op23f.eps  
Figure 2-11. Setting the Scan Interval  
2-17  
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2635A  
Users Manual  
Setting the Measurement Rate  
Perform the procedure in Figure 2-12 to set a fast or slow [default] measurement rate.  
The measurement rate affects the time required to scan the configured channels.  
However, the fast mode sacrifices one digit of measurement resolution. For example, a  
temperature reading of 22.4ºC in the slow mode would become 22ºC in the fast mode, or  
27.858V dc in the slow mode would become 27.86 V dc in the fast mode. The fast mode  
is normally used to capture rapidly changing measurements or to speed up the  
measurement portion of the scan interval.  
SHIFT  
Setting the Measurement Rate. Press the  
SHIFT key and then the right-arrow key to access  
RAtE  
FASt  
SLO  
the measurement rate menu. Press the up/down  
arrow keys to select either SLO (Slow) or FASt  
(Fast), then press the ENTER key.  
Typical  
Required  
ENTER  
op24f.eps  
Figure 2-12. Setting the Measurement Rate  
Setting the Alarms  
Perform the procedure in Figure 2-13 to set alarm limits for any configured channel. In  
preparation, the instrument must be in the inactive mode (not scanning or monitoring)  
and the desired channel must be configured with a measurement function (see Figures 2-  
4 to 2-9) and selected (see Figure 2-3). To exit at any time, press the C key; however,  
any alarm parameters previously entered will remain. Two alarm limits, alarm 1 and  
alarm 2, can be defined for each channel. If applied to a channel with Mx+B scaling, the  
alarm is based on the scaled values. An alarm occurs when the measured value on the  
channel moves above the HI (High) or below the LO (Low) value. Alarms can start  
autoprinting (Figure 5-3), start scanning with the Monitor-Alarm trigger option (Figure  
2-19), or trigger other functions via the rear panel digital outputs. In the inactive mode,  
any selected channel that is programmed with alarm limits will display LIMIT plus 1  
and/or 2 to show which alarms have been set. In the different operating modes, the front  
panel will provide an indication of a channel in an alarm condition. Each is discussed  
below.  
Alarm Indications While Scanning  
If a scanned channel is in an alarm condition during the scan, the ALARM annunciator is  
turned on (dim display). If all alarm conditions clear during the next scan, the ALARM  
annunciator is turned off. See Figure 2-15 for information about the Scan Mode.  
2-18  
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Front Panel Operations  
Setting Operating Conditions  
2
Alarm Indications While Monitoring  
If the channel being monitored is in an alarm condition, the alarm limit 1 and/or 2  
annunciators will be turned on, and the ALARM annunciator blinks bright/dim. The  
alarm limit annunciator indicates which alarm has been exceeded. If the monitored  
channel is not in alarm, the ALARM annunciator will be off, unless scanning and some  
other channel is in alarm, then the ALARM indicator has a steady dim display. See  
Figure 2-17 for information about the Monitor Mode.  
Alarm Indications While Reviewing  
If the channel being reviewed had been in an alarm condition, the ALARM and alarm  
limit 1 and/or 2 annunciators will be turned on. The alarm limit annunciator indicates  
which alarm has been exceeded. See Figure 2-18 for information about the Review  
Mode.  
Clearing Alarm Parameters from a Channel  
To clear alarm parameters from a channel, the alarm can be programmed to OFF for both  
alarm 1 and alarm 2, or the channel function can be changed to any other selection,  
including OFF.  
Alarm Outputs for Channel 0 to 3 Using the Alarm Outputs Connector  
A dedicated transistor-transistor logic (TTL) voltage output is available for channel 0 to  
channel 3 alarms, via the rear panel ALARM OUTPUTS connector. (See Chapter 1 of  
this manual for connection information.)If a channel is not in alarm, the voltage output at  
a connector terminal is a logical high (nominal +5V dc); if a channel is in alarm, the  
output is a logical low (nominal +0.7V dc). Alarm outputs are set following each scan.  
As shown in Table 2-4, there are 16 different alarm combinations. The decimal  
equivalent of the binary half-byte formed by Channel 3 to Channel 0 has significance in  
autoprinting operations. (See the following discussion on autoprinting.)  
Alarm Outputs for Channels 4 to 20 Using the Digital I/O Connector  
A shared transistor-transistor logic (TTL) voltage output is available for channel 4 to  
channel 20 alarms via the rear panel DIGITAL I/O connector, using terminals I/O 7 to  
I/O 4. (See Chapter 1 of this manual for connection information.)If a channel is not in  
alarm, the voltage output at a connector terminal is a logical high (nominal +5V dc); if a  
channel is in alarm, the output is a logical low (nominal +0.7V dc). Alarm outputs are set  
following each scan. As shown in Table 2-5, the alarm outputs for channels 4 to 20 are  
ORed in groups. For example, a logical low at I/O 7 indicates that channel 7 or 11 or 15  
or 19 is in an alarm condition. Dedicated alarm channels are available only for channels  
0 to 3 (see the above). Assigning alarms to channels 4 to 20 does not disable the  
associated I/O output from use by commands from the computer interface. (See using the  
"Digital Input/Output Lines" under "Additional Features.") The decimal equivalent of  
the binary byte formed by I/O 7 to I/O 0 has significance in autoprinting operations (see  
the following discussion) and for certain commands in the instrument command set, e.g.,  
LOG?.  
2-19  
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2635A  
Users Manual  
Table 2-4. TLL Alarm Outputs (Channels 0 to 3)  
Channel 2 Channel 1 Channel 0  
0 (Alarm) 0 (Alarm) 0 (Alarm)  
Channel 3  
0 (Alarm)  
Decimal  
0
0
0
0
1 (No Alarm)  
1
0
0
1 (No Alarm)  
0
1
0
1
0
1
0
1
0
1
0
1
0
1
2
0
0
1
0
0
1
1
0
0
1
1
0
0
1
1
3
0
1 (No Alarm)  
4
0
1
5
0
1
6
0
1
7
1(No Alarm)  
0
8
1
0
9
1
0
10  
11  
12  
13  
14  
15  
1
0
1
1
1
1
1
1
1
1
1 = No Alarm  
0 = Alarm  
Note 1. The decimal equivalent of the binary half-byte formed by Channel 3 to Channel 0 is used in  
autoprint functions.  
Note 2. The TTL alarm outputs are via the ALARM OUTPUTS rear panel connector.  
Alarms and Autoprinting  
Alarm conditions are indicated for each scanned channel when using the autoprint  
function, and the ALM (Alarm) and DIO (Digital I/O) conditions are summarized with a  
decimal number. (See Tables 2-4 and 2-5.)An alarm condition can be used to turn  
autoprinting on and off by selecting "Print" (printer) or "both" (printer and memory card)  
as a data destination, and the data mode as ALAr (Alarm) (see Figure 5-3). When  
scanning using the front panel Q key, the printer will print measurement results when  
any scanned channel is in alarm. If scanning using the alarm trigger (see Figure 2-19),  
the printer will print measurement results only when the monitored channel is in alarm.  
Alarms and Monitor-Alarm Triggering  
An alarm condition, coupled with the Monitor Mode, can be used to start and stop  
measurement scans (see Figure 2-19). When an alarm occurs, scanning begins, and when  
the alarm clears, scanning stops.  
Alarms and Mx+B Scaling  
Alarm settings are affected by Mx+B scaling. The Mx+B scaling determines the value  
that the instrument displays, and the alarms are configured for these values.  
2-20  
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Front Panel Operations  
Setting Operating Conditions  
2
Table 2-5. TTL Alarm Outputs (Channels 4 to 20)  
Channels Channels Channels  
6 -or- 5 -or- 4 -or-  
Channels  
7 -or-  
11 -or-  
15 -or-  
10 -or-  
14 -or-  
9 -or-  
13 -or-  
8 -or-  
12 -or-  
19  
18  
17  
16 -or-  
20 -or-  
I/O 7  
I/O 6  
I/O 5  
I/O 4  
Decimal  
0 (Alarm)  
0 (Alarm)  
0 (Alarm)  
0 (Alarm)  
31  
0
1 (No Alarm)  
0
1
1
1 (No Alarm)  
1 (Alarm)  
127  
191  
223  
239  
255  
1 (No Alarm)  
1
1
1
1
0
1
1
1
1
0
1
1
1 = No Alarm  
0 = Alarm  
Note 1. The decimal equivalent of the binary byte formed by Channel 4 to Channel 20 is used in autoprint  
and computer functions. The decimal values shown here are based on I/O 3 to I/O 0 being equal to logical 1.  
Note 2. The above shows the least complicated Digital I/O alarm configurations. Multiple alarms plus the use  
of I/O terminals 3 to 0 can conceivably use all 255 digital I/O combinations.  
Note 3. The TTL alarm outputs are via the DIGITAL I/O rear-panel connector  
Example: A logical 0 at I/O 7 terminals indicates an alarm condition for channel 7, or 11, or 15, or 19. Only  
channels 0 to 3 have dedicated alarm outputs on the ALARM OUTPUTS connector.  
2-21  
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2635A  
Users Manual  
ALRM  
ENTER  
ENTER  
Selecting Alarm 1 or Alarm 2. Press the ALRM  
(Alarm) key to access the alarm selection menu.  
Use the up/down arrow keys to select alarm 1 or  
2, then press the ENTER key.  
LIMIT  
1
2
Selecting the Alarm Mode. Press the up/down  
arrow keys to select an alarm mode, OFF (Off), HI  
(High), or LO (Low), then press the ENTER key.  
LIMIT  
OFF  
HI  
LO  
Selecting the Alarm Numerical Value. Press  
the up/down and left/right arrow keys to enter a  
five digit number that defines the numerical value  
for the alarm, ignoring the decimal point or scale  
multiplier. The column being configured will have  
a bright display. For example, for an alarm of  
132.75V ac, enter +13275. When the entry is  
correct, press the ENTER key.  
LIMIT  
± 0 0 0 0 0  
- to -  
± 9 9 9 9 9  
ENTER  
ENTER  
ENTER  
Selecting the Alarm Decimal Value. Press the  
left/right arrow keys to position the decimal point  
in the number selected in the previous step. For  
the example above, the settings would be 132.75.  
When the decimal point is correct, press the  
ENTER key.  
LIMIT  
X
.
X X X X  
X X X  
X X  
X X  
X X X  
X X X X  
.
.
.
X
Selecting the Alarm Scale Multiplier. Press the  
up/down arrow keys to select the desired  
multiplier: x1 (x1), m (x .001), M (x1,000,000), or  
k (x1,000). For the example above, the 132.75  
multiplier would be x1. When the multiplier is  
correct, press the ENTER key. If alarm 1 is  
configured, the procedure continues for alarm 2.  
If alarm 2 is configured, the procedure terminates.  
LIMIT  
x1  
m
M
k
Typical  
Required  
op25f.eps  
Figure 2-13. Setting the Alarms  
2-22  
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Front Panel Operations  
Setting Operating Conditions  
2
Setting the Mx+B Scaling  
Perform the procedure in Figure 2-14 to set the Mx+B scaling for any configured  
channel. In preparation, the instrument must be in the inactive mode (not scanning or  
monitoring) and the desired channel must be configured with a measurement function  
(see Figures 2-4 to 2-9) and selected (see Figure 2-3). To exit at any time, press the C  
key; however, any Mx+B parameters previously entered will remain. Scaling allows a  
measurement value (x) to be modified with a fixed multiplier (M) and a fixed offset (B).  
A channel with scaling other than the default of 1x+0 will display Mx+B when the  
channel is selected. When scaling is used, only a number is displayed; function  
identifiers such as ºC, Hz, , VAC, and VDC are removed. If the results from Mx+B  
scaling are nonsense, double check the signs and multiplier values for M and B.  
Examples  
Multiplier. If a pressure transducer provides 100 mV for 100 PSI, 200mV dc for 200  
PSI, etc., the instrument would read directly in PSI with a multiplier of 1000, or M=+1k  
and B=000.00. For example, a PSI of 156.98 would display the number 156.98.  
Offset. If you are monitoring line voltage of 115V ac and you want the instrument to  
display the variations above and below 115V ac instead of the actual voltage, the  
instrument would display the differences by subtracting -115 from the measurements, or  
B=-115.00 (M=1.0). For example, 117.21V ac would display only the number 2.21;  
113.45V ac would display the number -1.55.  
Multiplier and Offset. If the instrument is measuring temperature using the ºF scale, but  
you want it to display the measurements in ºC, the conversion formula ºC=5/9(ºF-32),  
rewritten in decimal ºC=.55555ºF-17.777, could make the conversion with M=+.55555  
(entered as +555.55m) and B=-017.78. For example, 72.2 ºF would display the number  
22.28.  
Restrictions  
Linearity. The transfer characteristic of the transducers or measurement modifications  
must be linear, with fixed multipliers (M) and fixed offsets (B).  
Overload (OL) Display. The decimal point location and scaling (m, X1, k, M) selected  
for the "B" value determines the scaling for the result. For example, if B=xxx.xx x1, the  
result will range over ±999.99 only. Anything greater than +999.99 or less than -999.99  
will show "OL" (overload).  
Clearing Mx+B Scaling from a Channel  
To clear Mx+B parameters from a channel, the Mx+B parameters can be programmed to  
1x+0 (M=1, B=0), or the channel function can be changed to any other selection,  
including OFF.  
2-23  
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2635A  
Users Manual  
Mx+B  
Selecting the M Numerical Value. Press the  
Mx+B key to access the Mx+B menu. Press the  
up/down and left/right arrow keys to enter a five  
digit number that defines the numerical value for  
the measurement multiplier, ignoring the decimal  
point or scale multiplier. The column being  
configured has a bright display. For example, for  
SET Mx+B  
± 0 0 0 0 0  
- to -  
± 9 9 9 9 9  
an M of 1000 (1k), enter +01000.  
entry is correct, press the ENTER key.  
When the  
ENTER  
Selecting the M Decimal Value. Press the  
left/right arrow keys to position the decimal point  
in the number selected in the previous step. For  
the example above, the setting would be +01.000.  
When the decimal point is correct, press the  
ENTER key.  
SET Mx+B  
X
.
X X X X  
X X X  
X X  
X X  
X X X  
X X X X  
.
.
.
X
ENTER  
Selecting the M Scale Modifier. Press the  
up/down arrow keys to select the desired scale  
modifier: X1 (x1), m (x .001), M (x1,000,000), or k  
(x1,000). For the example above, the +01.000  
scale modifier would be k. When the scale  
modifier is correct, press the ENTER key.  
SET Mx+B  
x1  
m
M
k
Typical  
ENTER  
Required  
(Continued on the next page)  
A
op26f.eps  
Figure 2-14. Setting the Mx+B Scaling  
2-24  
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Front Panel Operations  
Setting Operating Conditions  
2
(Continued from the previous page)  
A
Selecting the B Numerical Value. Press the  
up/down and left/right arrow keys to enter a five  
digit number that defines the numerical value for  
the measurement offset, ignoring the decimal  
point or scale multiplier. The column being  
configured has a bright display. For example, for  
a B of -115, enter -11500. When the entry is  
correct, press the ENTER key.  
SET Mx+B  
± 0 0 0 0 0  
- to -  
± 9 9 9 9 9  
ENTER  
Selecting the B Decimal Value. Press the  
left/right arrow keys to position the decimal point  
in the number selected in the previous step. For  
the example above, the setting would be -115.00.  
When the decimal point is correct, press the  
ENTER key.  
SET Mx+B  
X
.
X X X X  
X X X  
X X  
X X  
X X X  
X X X X  
.
.
.
X
ENTER  
Selecting the B Scale Modifier. Press the  
up/down arrow keys to select the desired scale  
modifier: X1 (x1), m (x .001), M (x1,000,000), or k  
(x1,000). For the example above, the -115.00  
scale modifier would be x1. When the scale  
modifier is correct, press the ENTER key.  
SET Mx+B  
x1  
m
M
k
Typical  
ENTER  
Required  
op26af.eps  
Figure 2-14. Setting the Mx+B Scaling (cont)  
2-25  
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2635A  
Users Manual  
Operating Modes  
With the channels configured and operating conditions set, the instrument is ready for  
operation in one of the following modes:  
Using the Scan Mode (Figure 2-15)  
Using the Monitor Mode (Figure 2-17)  
Using the Review Mode (Figure 2-18)  
Each operating mode is discussed below. To modify the operating mode with additional  
features, such as using the scan triggering, refer to the next main headings in this  
chapter, "Additional Features."  
Using the Scan Mode  
Perform the procedure in Figure 2-15 to start and stop the Scan Mode of operation. The  
Scan Mode can be started when the instrument is inactive, in Monitor (Figure 2-17), or  
Review (Figure 2-18). Measurement results can be sent to a memory card (see Chapter 3,  
"Memory Card Operations") and PC (see Chapter 4, "Computer Operations") or printer  
(see Chapter 5, "Printer Operations"). When using the Scan Mode with a memory card,  
consider each of the following topics. (Memory card error messages are summarized in  
Figure 2-16.)  
Memory Card as a Data Destination  
Measurement data is not automatically sent to the memory card. Measurement data can  
be sent to a printer/PC, to the memory card, to both printer/PC and memory card, or to  
neither. If either the printer/PC or memory card, or both are selected, the PRN  
annunciator will be on. See Figure 3-4 to set the destination and mode for sending  
measurement data to the memory card.  
Memory Card Formatting  
When the instrument is inactive (not scanning or monitoring), insert a memory card. An  
immediate error Err 1/CArd indicates the memory card is not initialized (formatted). See  
Figure 3-3 to initialize a memory card.  
Memory Card Capacity  
A memory card that fills during scanning displays the error Err 3/FULL, meaning  
readings are being saved in internal memory (75 scans maximum) and another card  
should be inserted. The error changes to Err 4/FULL if the internal memory fills, saving  
only the most recent 75 scans. When inserted, the replacement card is updated with the  
scans in memory.  
Memory Card Files  
Data files (dAtxx) are opened manually (see Figure 3-8) or prompted by pressing Q.  
Press E to accept file names or use the up/down and left/right arrow keys to select a  
file name and then press E. If a data file cannot be opened, error Err 2/FILE will be  
displayed, meaning all files dAt00 to dAt99 already exist or the selected file name is  
already assigned.  
Memory Card Exchange During Scanning  
Eject the active card when the BUSY indicator is off and replace with another card. The  
instrument opens the same file name on the new card. If this file cannot be opened, Err  
2-26  
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Front Panel Operations  
Operating Modes  
2
3/bAd is displayed (see Figure 2-16). Err4/bAd indicates the internal memory is full,  
saving only the most recent 75 scans. The new card is updated with the scans in memory.  
Memory Card Data Extraction  
Measurement data recorded onto a memory card can be read only by a PC running  
Starter or Logger applications software. If you want to have a copy of the measurement  
data when it is being recorded, connect a printer during scan operations (see Chapter 5,  
Printer Operation). If using a printer, verify the data destination is "both" (memory  
card/printer) (see Figure 5-3).  
Starting the Scan Mode. Press the SCAN key to  
start scanning. If the data destination includes  
SCAN  
the memory card and a data file has not been  
opened, a dAtxx file will be displayed. If an error  
message appears, refer to Figure 2-16.  
CH  
SCAN ON  
SCAN  
0:00:00  
Path to  
OPEn  
dAtxx  
menu.  
Opening a Data (dAtxx) File. Press ENTER to  
open the suggested file or use the cursor keys to  
select a file name (00 to 99), then press ENTER.  
If an error message appears, refer to Figure  
2–16. Press the CANCL key to exit without  
opening a file or starting scanning.  
OPEn  
dAtxx  
ENTER  
Stopping the Scan Mode. Press the SCAN key  
again to stop the scan mode (-OFF- will be  
displayed momentarily). If SCAN is pressed  
during the measurement interval, the  
measurements will be completed.  
SCAN  
SCAN OFF  
SCAN  
- OFF -  
SHIFT  
Starting the Single Scan Mode. Press the  
SHIFT key then then SCAN key for a single  
measure-ment scan. If the data destination  
includes the memory card and a data file has not  
been opened, a dAtxx file will be displayed. If an  
error message appears, refer to Figure 2-16.  
SCAN  
SINGLE  
SCAN  
CH  
SCAN  
0:00:00  
Path to  
OPEn  
dAtxx  
menu.  
Opening a Data (dAtxx) File. The suggested  
dAtxx file can be opened by pressing ENTER, or  
the cursor keys can be used to select a file name  
(00 to 99), then press ENTER. If an error  
message appears, refer to Figure 2-16. Press  
the CANCL key to exit without opening a file.  
OPEn  
dAtxx  
ENTER  
op27f.eps  
Figure 2-15. Using the Scan Mode  
2-27  
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2635A  
Users Manual  
Memory Card Error Messages  
Any illegal memory card operation results in a double "beep" and an error display as  
shown in Figure 2-16. If the instrument is scanning and in the Monitor Mode or Review  
Mode, only the double beep will be heard for a memory card error. Error messages are  
acknowledged by pressing the E or key or by ejecting the memory card.  
Card error. Card is missing, unformatted, full of  
data, or the write-protect switch is set to "read  
only." If error occurs when card is inserted, card  
is unformatted. To format a card, see Figure 3-3.  
To erase files, see Figure 3-7 (SEtxx files) or 3-9  
(dAtxx files). To set write-protect switch, see  
Figure 3-1.  
File error. Unable to open a file. The selected  
file name is already assigned or all file names  
have been used (00 to 99). Select another file  
name, erase files (Figures 3-7 or 3-9), or use  
another card.  
Card problem (scans saved). Scanned data is  
being stored in internal memory (75 scans  
maximum). Take action or the internal memory  
will overflow and data will be lost. Insert a usable  
replacement card and stored scans will be  
transferred to the new card. If action is delayed,  
the error message changes to Err 4.  
Card problem (scans lost). The most recent 75  
scans are stored in internal memory and the  
oldest scans are being discarded. Insert a usable  
replacement card and the stored scans will be  
transferred to the new card.  
Replacement card error. The replacement card  
is either unformatted, full of data, the identical file  
name used for the current scan already exists, or  
the write-protect switch is in "read only." Use  
another card or stop scanning and correct the  
problem. Display alternates with Err 3 or Err 4.  
Active card error. The active card recording  
measurement data is full. Install a replacement  
card and stored scans will be transferred to the  
new card. Display alternates with Err 3 or Err 4.  
Active card error. The active card has been  
removed during scanning. Reinsert the same  
card or install a replacement card. Stored scans  
will be transferred to the inserted card. Display  
alternates with Err 3 or Err 4.  
op28f.eps  
Figure 2-16. Memory Card Error Messages  
2-28  
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Front Panel Operations  
Operating Modes  
2
Using the Monitor Mode  
Perform the procedure in Figure 2-17 to start and stop the Monitor Mode of operation.  
The Monitor Mode can be started when the instrument is in the inactive mode or in the  
Scan Mode. The Monitor Mode commands the instrument to display the present  
measurement for any selected channel (except channels set to OFF) and to display alarm  
information if the channel is in alarm. If the Monitor Mode is used without the Scan  
Mode, the instrument operates like a multimeter. If the Monitor Mode is used with the  
Scan Mode, the instrument also operates like a multimeter but measurements can be  
recorded into memory, printed out, and reviewed (maximum, minimum, last values). The  
Monitor-Alarm triggering option uses the Monitor Mode to start or stop scans when a  
selected channel goes into or out of alarm (see Figure 2-19). If the instrument is in the  
Monitor Mode and scanning using the memory card, any illegal memory card operations  
are noted only with a double "beep." When you hear a double beep, exit the Monitor  
Mode and investigate the memory card error (see Figure 2-16).  
MON  
Starting the Monitor Mode. Press the MON key  
to start the Monitor Mode. Use the up/down arrow  
MON  
keys to select any configured channel and  
display the current measurement. Any monitored  
channel using autoranging will display AUTO.  
When the instrument is in the Monitor Mode, an  
internal relay closes every 10 seconds as part of  
the meter housekeeping activities. Relay closures  
are heard as a series of low-level audio "clicks"  
coming from the instrument.  
CH  
MONITOR  
ON  
XX.XXX  
Stopping the Monitor Mode. Press the MON  
key again to stop the Monitor Mode (-OFF- will be  
displayed momentarily). If the meter is in the  
Scan Mode, the front panel changes to the scan  
channel/interval timer display.  
MON  
MONITOR  
OFF  
MON  
- OFF -  
op29f.eps  
Figure 2-17. Using the Monitor Mode  
2-29  
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2635A  
Users Manual  
Using the Review Mode  
Perform the procedure in Figure 2-18 to operate the Review Mode of operation. The  
Review Mode is used any time during or after operation of the Scan Mode. While the  
instrument is in the Scan Mode, the last, maximum, and measurements for each scanned  
channel are stored in memory and updated with each scan, forming the Review Array.  
For example, during scan operations, N can be used to monitor the maximum  
measurement of a channel in real time. The Review Array is cleared by a control  
sequence (see Figure 2-18 below), or by changing any parameter of any channel or the  
measurement rate. The Review Array can be printed out using the L key (see Figure  
5-4). If the instrument is in the Review Mode and scanning using the memory card, any  
illegal memory card operations is noted only with a double "beep." If a double beep is  
heard, exit the Review Mode and check the memory card error (see Figure 2-16).  
REVIEW  
Examining the Review Values. Press the  
REVIEW key to start the Review Mode. Use the  
up/down arrow keys to select the channel for  
REVIEW  
CH  
review, then use the left/right arrow keys to view  
the LAST (Last), MIN (Minimum), and MAX  
(Maximum) values recorded during the past scan  
intervals (scan can be active or inactive). Repeat  
for each channel of interest. A series of dashes,  
REVIEW  
- - - - -, indicates all review data has been cleared  
either by a control sequence (below), or by  
changing any parameter of any channel. OL  
LAST  
MIN  
MAX  
indicates an overload. Press the REVIEW key to  
exit the Review Mode. If not cleared, review  
values will remain in memory for update with the  
next scan interval.  
REVIEW  
REVIEW  
SHIFT  
REVIEW  
REVIEW  
Clearing the Review Array. Press the Review  
key to start the Review Mode. Press the SHIFT  
key and then the REVIEW key to clear all review  
data from all channels. If the scan mode is not  
active, the display will change to dashes (- - - - -).  
If the scan mode is active, new values will  
appear. Press the REVIEW key again to exit the  
Review Mode.  
REVIEW  
- - - - -  
op30f.eps  
Figure 2-18. Using the Review Mode  
2-30  
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Front Panel Operations  
Additional Features  
2
Additional Features  
The following additional features allow the instrument to serve in a variety of  
applications:  
Scan Triggering Options (Figure 2-19)  
Totalizer Operation (Figure 2-20)  
Digital Input/Output Lines  
Setting Date and Time (Figure 2-21)  
Reading Instrument Software Versions (Figure 2-22)  
Returning to the LOCAL Mode (Figure 2-23)  
Front Panel Key Lockout Option (Figure 2-24)  
Scan Triggering Options  
Perform the procedure in Figure 2-19 to select a triggering option, which can be applied  
when the instrument is in the inactive mode (not scanning or monitoring). Normally, a  
scan is started by pressing the Q key, but two options can be selected to start a scan  
from either an external trigger input or from a monitor-alarm condition. The Q key  
overrides a triggering option.  
External Trigger  
The external trigger input starts a scan from a contact closure or TTL input applied to the  
TR and GROUND inputs on the rear panel ALARM OUTPUTS connector (see Figure 1-  
7). This option lights the EXT TR annunciator.  
Monitor-Alarm Trigger  
The Monitor-Alarm trigger starts scanning from a channel that goes into an alarm while  
being monitored in the Monitor Mode. When the monitored channel goes into alarm, the  
instrument scans for as long as the alarm condition exists. This option lights the TR  
annunciator.  
Triggering Options and Memory Card Operation  
To verify the equipment setup when the memory card is used to record data, use the  
Single Scan mode (see Figure 2-15) to record a single scan. Any problems with the  
memory card or setup can be observed and corrected. If a triggering option triggers  
scanning without an open memory card dAtxx file, the instrument will automatically  
open a file when a usable memory card is in the instrument. If no memory card is  
installed or the memory card is not usable, the most recent 75 scans are saved in an  
internal memory. To record the saved scans, insert a usable memory card and open a file  
(see Figure 3-8). The stored scans will be transferred to the card.  
2-31  
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2635A  
Users Manual  
SHIFT  
MON  
Selecting a Trigger Option. Press the SHIFT  
key and then the MON key to access the trigger  
option menu. Press the up/down arrow keys to  
select either ALAr (Alarm) (Monitor-Alarm trigger),  
On (On) (External trigger), or OFF (Off) (no  
trigger option selected), then press the ENTER  
key.  
TRIg  
ALAr  
On  
OFF  
Typical  
ENTER  
Required  
op31f.eps  
Figure 2-19. Scan Triggering Options  
Totalizer Operation  
Perform the procedure in Figure 2-20 to use the totalizer feature. The totalizer count can  
be monitored when the instrument is active or inactive. The totalizer is an internal  
counter that sums contact closures or voltage transitions. Connection is at the rear panel  
DIGITAL I/O connector, pins SUM and GROUND. A contact closure between SUM and  
GROUND or a voltage transition applied to SUM (referenced to GROUND), will cause  
the totalizer to advance by one count. The maximum count allowed is 65535 and the  
maximum count rate is 5 kHz. Voltages trigger on a low-to-high transition at a nominal  
threshold of +1.4 volts. A contact debounce feature is available when the instrument is  
operated through a computer interface. (See Chapter 4, "Computer Operations.")  
2-32  
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Front Panel Operations  
Additional Features  
2
Reading the Totalizer Count. Press the TOTAL  
totAL  
key to view the contents of the totalizer counter.  
The maximum count is 65535. If the maximum  
count is exceeded, the display will show OL  
(Overload). Press the TOTAL key again to exit.  
To reset the counter to zero, see below, Erasing  
the Totalizer Count.  
XXXXX  
TOTAL  
TOTAL  
Erasing the Totalizer Count. Press the TOTAL  
key to view the contents of the totalizer counter.  
Press the SHIFT key and then the TOTAL key to  
reset the counter to zero. Press the TOTAL key  
again to exit.  
totAL  
XXXXX  
TOTAL  
SHIFT  
totAL  
TOTAL  
TOTAL  
0
op32f.eps  
Figure 2-20. Totalizer Operation  
Digital Input/output Lines  
There are no front panel controls or annunciators for the digital input/output (I/O) lines,  
I/O 7 to I/O 0. Connection to the eight I/O lines is via the rear panel DIGITAL I/O  
connector. If a logic low is applied to any line, the instrument treats it as an input; if the  
instrument sets a line to logic low, the instrument treats it as an output. An output low  
condition takes precedence over an input high condition. All digital I/O lines are  
controlled by a computer interface (see Chapter 4, "Computer Operations"); however, as  
a default, lines I/O 7 to I/O 4 are used to output alarm status conditions for channels 4 to  
20 (see Table 2-5). An instrument-generated I/O line alarm output takes precedence over  
any other configuration.  
All Digital I/O lines are set high (non-active) whenever power is cycled. These lines  
remain high until an alarm condition or computer interface command changes an output  
state.  
Note  
Measurements taken with the Monitor function do not affect the digital  
outputs.  
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2635A  
Users Manual  
Setting Date and Time  
Perform the procedure in Figure 2-21 to set the instrument internal clock and calendar,  
which must be correct since measurements are tagged with this time and date. The built-  
in clock accuracy is a nominal one minute per month. Once set to the correct date and  
time, clock and calendar operation is automatic and no further action is required.  
SHIFT  
INTVL  
Selecting the Year. Press the SHIFT key and  
then the INTVL key to enter the date/time menu.  
YEAR  
0 0  
- to -  
9 9  
With YEAR displayed, use the up/down and  
left/right arrow keys to select the two numbers for  
the correct year, for example, 94 for 1994, then  
press the ENTER key.  
ENTER  
Selecting the Month and Day. With Mn.dY  
(Month.Day) displayed, use the up/down and  
left/right arrow keys to select four numbers for the  
correct month and day, for example, 07.21 for  
July 21, then press the ENTER key.  
Mn.dY  
0 0 . 0 0  
- to -  
9 9 . 9 9  
ENTER  
Selecting the Hour and Minute. With Hr:Mn  
(Hour:Minute) displayed, use the up/down and  
left/right arrow keys to select four numbers for the  
correct hour and minute (24-hour clock), for  
example, 14.38 for 2:38 pm, then press the  
ENTER key.  
Hr:Mn  
0 0 . 0 0  
- to -  
9 9 . 9 9  
Typical  
Required  
ENTER  
op33f.eps  
Figure 2-21. Setting Date and Time  
2-34  
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Front Panel Operations  
Additional Features  
2
Reading Instrument Software Versions  
Perform the procedure in Figure 2-22 to view the version of the internal software that is  
controlling the instruments operation. Two software versions are identified with this  
procedure: the main software that operates all instrument functions, and the analog-to-  
digital software that operates the instrument analog-to-digital converter.  
Reading the Software Versions. Press the left  
and right arrow keys simultaneously to generate a  
display that shows the software versions in the  
+
following format:  
A 4.7  
6.3  
Analog-to-Digital  
Converter Software  
Version (Ver. 4.7  
shown)  
Main Software  
Version (Ver. 6.3  
shown)  
CANCL  
Press the CANCL key to exit.  
op34f.eps  
Figure 2-22. Reading Instrument Software Versions  
Returning to the Local Mode  
Perform the procedure in Figure 2-23 to return the instrument from the remote mode to  
the local mode. When the instrument is operated over the RS-232 computer interface, the  
computer can disable all front panel controls except the Q key, which lights the REM  
annunciator (bright). If the REM annunciator is dim, the front panel keys are locked out  
(see Figure 2-24).  
Returning to the LOCAL Mode. Press the  
SHIFT  
SHIFT key to return instrument control from  
RS–232 computer interface control to front panel  
control. When the computer has control, the  
REM annunciator is on (bright) and only the  
SCAN key operates, triggering single scans.  
A
return to LOCAL control is allowed at any time,  
even during scanning. (This assumes the RWLS  
computer command has not been invoked. See  
Section 4 for information on commands REMS,  
RWLS, and LOCS.)  
op35f.eps  
Figure 2-23. Returning to LOCAL Mode  
2-35  
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2635A  
Users Manual  
Front Panel Key Lockout Options  
Perform the procedure in Figure 2-24 to lockout the front panel key functions. There are  
three lockout features:  
Monitor Mode Lockout  
Review Mode Lockout  
A third lockout can be enabled only from the computer interface (see the LOCK 3  
command in Chapter 4).  
The Monitor Mode lockout is entered when the instrument is in the Monitor Mode; the  
Review Mode Lockout is entered when the instrument is in the Review Mode. When  
lockout is enabled, the instrument becomes "locked" in a selected mode preventing any  
unauthorized instrument operations. A repeat of the lockout keystrokes releases the  
lockout and the instrument resumes normal operation. When in the locked condition, the  
front panel REM indicator is on (dim). This feature allows inexperienced operators to  
use the instrument without having to change the mode of operation. The keystrokes used  
to enable or disable the lockout option is normally not revealed to unauthorized  
personnel.  
Lockout Enable. Press the FUNC and Mx+B  
keys at the same time to lock out the front panel  
REM  
key functions appropriate to the selected mode.  
The REM (Remote) annunciator will light.  
MODE]  
[MONITOR  
FUNC  
Lockout  
- or -  
+
on  
Mx+B  
[REVIEW  
MODE]  
Lockout Disable. Press the FUNC and Mx+B  
keys at the same time to exit the lockout mode.  
The REM (Remote) annunciator will go off and  
normal key function will return.  
[MONITOR  
MODE]  
FUNC  
Lockout  
off  
- or -  
+
Mx+B  
[REVIEW  
MODE]  
op36f.eps  
Figure 2-24. Front Panel Key Lockout Options  
Instrument Interfaces  
Front panel operations that involve interfacing with memory cards, PCs, printers, and  
modems are described in separate manual chapters, as follows.  
Memory Card Interface  
The Memory Card Interface is described in detail in Chapter 3, "Memory Card  
Operations."  
2-36  
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Front Panel Operations  
Instrument Interfaces  
2
RS-232 Computer Interface  
The Computer Interface is described in detail in Chapter 4, "Computer Operations."  
Using the RS-232 Computer Interface With a Printer  
The Printer Interface is described in detail in Chapter 5, "Printer Operations."  
Using the RS-232 Computer Interface With a Modem  
The Modem Interface is described in detail in Chapter 6, "Modem Operations."  
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2635A  
Users Manual  
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Chapter 3  
Memory Card Operations  
Title  
Page  
Summary of Memory Card Operations ............................................................. 3-3  
Memory Card Files ....................................................................................... 3-3  
Setup Files..................................................................................................... 3-4  
Data Files ...................................................................................................... 3-4  
Memory Card Capacity................................................................................. 3-4  
Memory Card Battery ................................................................................... 3-5  
Inserting and Removing the Memory Card ....................................................... 3-5  
Inserting a Memory Card .............................................................................. 3-5  
Removing a Memory Card............................................................................ 3-5  
Changing the Memory Card During Scanning.............................................. 3-5  
Setting the Memory Card Write-protect Feature .......................................... 3-5  
Installing or Replacing the Memory Card Battery ............................................ 3-5  
Initializing a Memory Card ............................................................................... 3-7  
Recording Measurement Results During Scanning........................................... 3-8  
Setup File Procedures........................................................................................ 3-9  
Using Setup Store.......................................................................................... 3-9  
Using Setup Load.......................................................................................... 3-10  
Using Setup Erase ......................................................................................... 3-11  
Data File Procedures ......................................................................................... 3-12  
Using Data Open........................................................................................... 3-12  
Using Data Erase........................................................................................... 3-13  
Setup and Data Files Directory ......................................................................... 3-14  
Setup and Data File Current Status ................................................................... 3-15  
Memory Card File Operations to and from a PC .............................................. 3-16  
3-1  
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2635A  
Users Manual  
DATA BUCKET  
REVIEW  
LAST  
HYDRA  
CH  
mA  
mVDCAC  
Hz  
M
k
V
COM  
REVIEW  
CLEAR  
PRINT  
MODE  
INTVL  
SCAN  
CLOCK  
ALRM  
FUNC  
Mx+B  
SINGLE  
300V  
MAX  
RATE  
MON  
TOTAL  
ZERO  
ENTER  
LIST  
SHIFT  
CANCEL  
TRIGS  
COMM  
LOCAL  
BATT  
BUSY  
MELCARD  
NFGFHMELCARD  
KB  
256  
NFGFHMELCARD  
NFGFHMELCARD  
op81f.eps  
3-2  
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Memory Card Operations  
Summary of Memory Card Operations  
3
Summary of Memory Card Operations  
Memory card operations use a small, lightweight memory card (Figure 3-1) to save and  
load setup files (instrument configurations) and to record measurement data during  
scanning. The memory card consists of static random-access memory (SRAM) powered  
by an internal battery. Care should be taken not to drop or bend the card, and to keep it  
dry and away from high and low temperature extremes. Memory card operation is  
allowed in the same temperatures and humidity specifications that apply to the  
instrument (see Appendix A, "Specifications"). SRAM memory cards are readily  
available from supply houses serving the computer industry, or from Fluke (see Table 1-  
2, "Options and Accessories").  
INSERTION  
DIRECTION  
68-PIN CONNECTOR  
256 KB  
SRAM  
WRITE-PROTECT SWITCH  
LITHIUM BATTERY 3 VOLTS  
op37f.eps  
Figure 3-1. Typical Memory Card  
Memory Card Files  
Two types of memory card files are used. Files that store instrument configurations are  
setup files, SEtxx, and files that store measurement data are data files, dAtxx, where xx  
is and integer from 00 to 99. The number xx can be assigned by the instrument or  
selected by the operator. When the assigned integer reaches 99, previous integers  
available from erased files or numbers skipped over are reassigned for subsequent new  
files. The memory card can contain a maximum of 100 SEtxx and 100 dAtxx files.  
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2635A  
Users Manual  
Setup Files  
When the front panel controls have been used to configure channels for a particular  
instrument application, including type of measurement, alarms, scaling, rate, and all  
other operating parameters, this configuration can be saved as a SEtxx files. If this is the  
first setup file saved on the memory card, the instrument will assign 00 for the file name  
SEt00, or you can select your own file number. The instrument displays only the SEtxx  
portion, but all files are appended with the extension .HYD. Subsequent setup files  
would be Set01, Set02, and so on. The user should note the file name assigned or  
selected for a particular instrument configuration. A directory of card files are easily  
viewed and print out using the directory feature (Figure 3-10). Setup files allow the  
entire instrument to b e configured for an operation in and instant. The “Logger”  
applications software can be used to create setup files that are tagged with a user-defined  
string.  
Data Files  
Data files, dAtxx, are opened automatically at scanning when the memory card is  
selected as a destination for measurement data. The display will indicate the file being  
opened. For example, pressing the Q key will display dAt00 (for the first data file on  
the memory card), which is acknowledged by pressing E, and then the scanning  
begins. A file number can be selected as well. The instrument displays only the dAtxx  
portion, but all files are appended with the extension .HYD. If scanning is stopped, then  
resumed without changing instrument configuration or the memory cared, the data will  
be appended to the opened file. If any parameter is changed or the memory card is  
changed, the next scan cycle will open a new dAtxx file. Extraction measurement data  
from the data files is accomplished by a PC running Starter or Logger applications  
software. The data is read to the PC from the memory card in the instrument, using an  
RS-232 link, or the memory card can be taken to a PC equipped with a memory card  
reader (optional - see Table 1-2, “Options and Accessories”). The PC Logger  
applications software allows separate data files to be edited and combined into a single  
file.  
Memory Card Capacity  
An empty 256K-byte memory card (supplied) will store 4,800 scans of ten channels; an  
empty 1M-byte memory card (optional) will store 19,800 scans of ten channels. SRAM  
memory cards are available in a variety of sizes. When scanning and recording data onto  
the memory card, the front panel indicates what percentage of the memory card has been  
used (Figure 3-2). For example, a display of 74Pct indicates 74% of the card has been  
used.  
SCAN  
PRN CH  
op38f.eps  
Figure 3-2. Front Panel Memory Card Percent Display  
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Memory Card Operations  
Inserting and Removing the Memory Card  
3
Memory Card Battery  
A typical SRAM is powered by an internal lithium 3-volt battery that has a minimum life  
of five years for a 256K-byte card, and two years for a 1M-byte card. If the battery  
voltage falls below 2.75 volts, the front panel BATT indicator will light (see Figure 1-1).  
Battery life is reduced in applications with high ambient temperature.  
Inserting and Removing the Memory Card  
Memory card operations that involve inserting and removing the card are described  
below. Any illegal memory card operations result in an instrument double "beep" and an  
error message. Error messages are summarized in Table 3-1.  
Inserting a Memory Card  
To insert the memory card into the instrument, orient the card so the insertion-direction  
arrows are on top and point towards the card reader slot. Push the card at the center of  
the edge into the slot until resistance is noted, then firmly push until seated in the  
connector. If the instrument responds with a double beep and error message, the inserted  
card is unformatted (see the initialization procedure in Figure 3-3).  
Removing a Memory Card  
To remove the memory card from the instrument, press the ejection button to the right of  
the card (see Figure 1-1). The button should be pressed firmly until it becomes flush with  
the instrument front panel. This action ejects the card from the connector and pushes it  
free of the reader assembly. Grasp the card and remove from the instrument.  
Changing the Memory Card During Scanning  
When recording measurement data to a memory card that is nearly full (as noted by the  
percent indication), remove the memory card in the normal way when the BUSY  
indicator is off. Then insert a new memory card (be sure it is formatted), which will  
automatically open a file with the same number and continue recording data. For  
example, if scanning started with dAt17 on the original card, dAt17 will be opened on  
the replacement card. If the same filed already exists on the replacement card, e.g.,  
dAt17, an error message appears. No data is lost during this operation as the instrument  
stores up to 75 scans when the memory card is removed during scanning, and the new  
memory card is immediately updated with this stored data. The PC software "Logger"  
allows separate memory card files to be combined into a single file.  
Setting the Memory Card Write-protect Feature  
The memory card (Figure 3-1) has a write-protect switch that can be positioned to  
prevent the writing of data to the card, the erasing of any dAtxx or SEtxx file, or the  
initialization of the memory card. Normally, this switch is placed in the read/write  
position. However, if the card has critical data that should be protected, the switch is  
placed in the write-protect (read only) position.  
Installing or Replacing the Memory Card Battery  
To install or replace the battery in the memory card, follow the instructions supplied  
with the memory card. A typical battery installation is shown in Figure 3-1. Memory  
card batteries are readily available from supply houses serving the computer industry  
(typically 3V dc, Panasonic BR2325, Maxell CR2025, or equal).  
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2635A  
Users Manual  
Table 3-1. Memory Card Error Codes  
Probable  
Error  
Cause  
Err 1 Card  
CARD ERROR- Unable to use a card (Note 1):  
Card is missing or card is not fully inserted.  
Card is unformatted.  
Install a memory card (Fig. 3-1).  
Initialize a memory card (Fig. 3-3).  
Reposition switch (Fig. 3-1).  
Write-protect switch in the read -only position.  
Card is 100% full of data  
Erase files (Fig. 3-7/3-9) or use another  
card.  
Err 2 FILE  
FILE ERROR- Unable to open a file (Note 1):  
The selected file name already exists.  
Choose another file name (Fig. 3-5/3-8)  
or erase files (Fig. 3-7/3-9).  
All file names are assigned (SEt00, SEt99 or  
dAt00 to dAt99).  
Erase files (Fig. 3-7/3-9) or use another  
card.  
Err 3 bAd  
CARD PROBLEM (Scans Saved) (Note 1):  
Card exchanged during scanning is  
unformatted.  
Use a formatted card (Note 2).  
Use a different card (Note 2).  
Use a different card (Note 2).  
Card exchanged during scanning is full of  
data.  
Replacement card has a duplicate file name.  
(Note 4).  
Err 4 bAd  
CARD PROBLEM (Scans Lost) (Note 1):  
Same as Err 3 bAd (Note 3).  
Err 3 FULL  
Err 4 FULL  
CARD IS FULL (Scans Saved) (Note 1):  
Card is 100% full of data.  
Use a different card (Note 2).  
CARD IS FULL (Scans Lost) (Note 1):  
Sane as Err 3 FULL (Note 3)  
Note 1: Err 1 and Err 2 are non-scanning errors that occur only before scanning starts. Err 3 and Err 4  
are scanning errors that occur only after scanning starts.  
Note 2: Err 3 indicates scans are being saved in an internal memory (75 scans) while the memory card  
error is being resolved. Err 4 indicates scans are bin lost because the internal memory overflowed (75  
scans) before the error was corrected. When a suitable exchange card is inserted, the internal memory  
updates the card with the stored scans.  
Note 3: When memory cards are exchanged during scanning and the replacement card has a problem,  
Err 3/Err 4 is appended with the word bAd. When the memory card used for scanning becomes full of  
data, Err 3/Err 4 is appended with the word FULL.  
Note 4: When memory cards are exchanged during scanning, the replacement card must have the same  
file name available as was used for the original scan. If this file name already exists on the replacement  
card, and Err 3/Err 4 will occur.  
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Memory Card Operations  
Initializing a Memory Card  
3
Initializing a Memory Card  
Perform the procedure in Figure 3-3 to initialize (format) a memory card. Memory cards  
can also be formatted at a PC if it is equipped with a memory card reader. (Formatting at  
a PC uses the format utility supplied with the memory card reader.)When the memory  
card is formatted, a standard DOS file system and directory are put into the memory on  
the card. To exit at any time (formatting not completed), press the C key.  
Note  
Any scan data that may be stored in the internal memory waiting to be  
written to a valid memory card (see paragraph 3-8 Changing the Memory  
Card During Scanning) will be lost when formatting a memory card.  
Selecting the INITIALIZATION mode. Insert the  
FILES  
Init  
StAt  
dir  
FILES  
memory card to be initialized. Press the FILES  
key to access the FILES menu. Press the  
up/down arrow keys until Init is displayed, then  
press the ENTER key. The menu changes to  
Init. If an error message appears, see Table 3-1.  
dAtA  
SEtUP  
ENTER  
Verifing the INIT mode. To verify the selection  
of the initialization mode, press the up/down  
arrow keys until yES is displayed in the Init menu,  
Init  
yES  
no  
then press the ENTER key.  
To exit the  
procedure, select no and then press the ENTER  
key. If yES is selected, the menu changes to  
SUrE.  
ENTER  
Initializating the memory card. Press the  
up/down arrow keys to select yES or no in the  
SUrE menu, then press the ENTER key. "yES"  
will initialize the memory card, erasing all  
previous data (if any); "no" cancels the  
procedure. If Err 1 CArd appears, the small  
switch on the card may be in the write-protect  
position. Reposition the switch and repeat this  
procedure.  
SUrE  
yES  
no  
Typical  
Required  
ENTER  
op39f.eps  
Figure 3-3. Initializing a Memory Card  
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2635A  
Users Manual  
Recording Measurement Results During Scanning  
Perform the procedure in Figure 3-4 to record measurement results onto the memory  
card. The destination for the scanned data can be the memory card, printer, both the  
memory card and printer, or no destination, where the results are not saved, except in the  
Review array (last, maximum, and minimum scanned values) and in the 100-scan  
internal memory FIFO (First In First Out) log queue. (The internal memory log queue is  
accessed only through the computer interface. See Chapter4, "Computer  
Operations.")The mode for recording to the memory card or printer can be all scanned  
data, scanned data only when any scanned channel is in alarm, or single scans when an  
alarm transitions into or out of alarm.  
Note  
Measurement results recorded onto a memory card are extracted only by a  
PC running the Starter or Logger applications software. If printed results  
are desired as well as recording to the memory card, then "both" must be  
selected in the procedure below and a printer must be connected to the RS-  
232 port. See Chapter5, Printer Operations, for more information.  
SHIFT  
FILES  
Setting the DESTINATION Parameter. Press  
the SHIFT key, release, then press the FILES  
dESt  
key to open the destination menu. Select both  
(Both) to route measurement data to both the  
memory card and printer; select Card (Card) to  
route measurement data just to the memory card.  
both  
Print  
CArd  
nonE  
ENTER  
Selecting the Destination MODE.  
The  
MOdE  
destination mode determines when the memory  
card should record. Select trAns (Transition) to  
record one complete scan when a channel has  
transitioned into or out of an alarm limit. Select  
ALAr (Alarm) to record all channel scans while  
any channel is in an alarm condition (stopping  
when all channels are out of alarm). Select ALL  
(All) to record all scans.  
trAnS  
ALAr  
ALL  
Typical  
ENTER  
Required  
op40f.eps  
Figure 3-4. Recording Measurement Results During Scanning  
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Memory Card Operations  
Setup File Procedures  
3
Setup File Procedures  
Perform the following procedures to LOAD, STORE, and ERASE memory card  
instrument configuration (SEtUP) files.  
Using Setup Store  
Perform the procedure in Figure 3-5 to save the current instrument configuration. The  
communication parameters: baud, parity, CTS, and echo, remain as set previously by the  
front panel controls or computer interface. The instrument automatically assigns the next  
sequential SEtxx file name. When SEt99 is reached, the instrument loops back to reuse  
previously assigned file names that have been erased or skipped over. To assign your  
own file name, use the up/down and left/right arrow keys when creating the file.  
Selecting the SETUP mode. Press the FILES  
FILES  
Init  
StAt  
dir  
FILES  
key to access the FILES menu. Press the  
up/down arrow keys until SEtUP is displayed,  
then press the ENTER key. The menu changes  
to SEtUP. If an error message appears, see  
Table 3-1.  
dAtA  
SEtUP  
ENTER  
Selecting the STORE mode.  
Press the  
SEtUP  
up/down arrow keys until StorE is displayed in  
the SEtUP menu, then press the ENTER key.  
The menu changes to StorE and a file name is  
displayed.  
ErASE  
StorE  
LOAd  
ENTER  
Storing a SEtxx File. Record the displayed  
SEtxx file name, where xx represents an  
instrument-assigned number between 00 and 99  
or use the up/down, left/right arrow keys to select  
the xx number. Press the ENTER key to store  
the file.  
StorE  
SEt99  
SEtxx  
SEt00  
Overwriting a SEtxx File. If the xx number  
selected in the previous step is already assigned,  
the existing file will be overwritten with the new  
file. If this is desired, select yES then press the  
ENTER key. If no is selected, the procedure will  
terminate. If an error message appears, see  
Table 3-1.  
SUrE  
yES  
no  
ENTER  
ENTER  
Typical  
Required  
op41f.eps  
Figure 3-5. Using SETUP STORE to Save Configuration Files  
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2635A  
Users Manual  
Using Setup Load  
Perform the procedure in Figure 3-6 to discard the current instrument configuration and  
load a configuration saved in a previous SETUP STORE operation (Figure 3-5). A  
configuration file includes channel configurations, scan interval, measurement rate,  
alarms, Mx+B scaling, and temperature unit (ºC or ºF). Communication parameters,  
baud, parity, CTS, and echo remain as set previously by the front panel controls. To exit  
at any time (file not loaded), press the C key.  
Selecting the SETUP mode. Press the FILES  
FILES  
Init  
StAt  
dir  
dAtA  
SEtUP  
FILES  
key to access the FILES menu. Press the  
up/down arrow keys until SEtUP is displayed,  
then press the ENTER key. The menu changes  
to SEtUP. If an error message appears, see  
Table 3-1.  
ENTER  
Selecting the LOAD mode. Press the up/down  
arrow keys until LoAd is displayed in the SETUP  
menu, then press the ENTER key. The menu  
changes to LoAd.  
SEtUP  
ErASE  
StorE  
LOAd  
ENTER  
Selecting a SEtxx File to LOAD. Press the  
up/down arrow keys until the SEtxx file to be  
loaded is displayed in the LoAd menu, where xx  
represents a number from 00 to 99, then press  
the ENTER key. After ENTER is pressed, the  
entire meter configuration changes to reflect the  
data stored in the selected SETUP file. A display  
of nonE indicates no setup files are stored.  
LoAd  
SEt99  
SEtxx  
SEt00  
Typical  
Required  
ENTER  
op42f.eps  
Figure 3-6. Using SETUP LOAD to Load Configuration Files  
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Memory Card Operations  
Setup File Procedures  
3
Using Setup Erase  
Perform the procedure in Figure 3-7 to remove a setup file from the memory card.  
Removing a file does not interrupt the sequential SEtxx file names assigned with the  
SEtUP STORE command. When SEt99 is reached, the instrument loops back to reuse  
previously assigned file names that have been erased or skipped over. To exit at any time  
(file not erased), press the C key.  
Selecting the SETUP mode. Press the FILES  
FILES  
Init  
StAt  
dir  
dAtA  
SEtUP  
FILES  
ENTER  
ENTER  
ENTER  
key to access the FILES menu. Press the  
up/down arrow keys until SEtUP is displayed,  
then press the ENTER key. The menu changes  
to SEtUP. If an error message appears, see  
Table 3-1.  
Selecting the ERASE mode.  
Press the  
SEtUP  
up/down arrow keys until ErASE is displayed in  
the SEtUP menu, then press the ENTER key.  
The menu changes to ErASE.  
ErASE  
StorE  
LOAd  
Selecting a SEtxx File to ERASE. Press the  
up/down arrow keys until the SEtxx file to be  
erased is displayed in the ErASE menu, where xx  
represents a number from 00 to 99, then press  
the ENTER key. The menu changes to SUrE.  
ErASE  
SEt99  
SEtxx  
SEt00  
Erasing a SEtxx File. Press the up/down arrow  
keys to select yES or no in the SUrE menu, then  
press the ENTER key. yES will erase the file, no  
will cancel the procedure and nothing will be  
erased. The procedure repeats after pressing  
ENTER, or displays nonE if there are no files to  
erase. Press the CANCL key to exit. If an error  
message occurs, see Table 3-1.  
SUrE  
yES  
no  
Typical  
Required  
ENTER  
op43f.eps  
Figure 3-7. Using SETUP ERASE to Delete Configuration Files  
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2635A  
Users Manual  
Data File Procedures  
Perform the following procedures to OPEN, LOAD, STORE, and ERASE memory card  
instrument data (DATA) files.  
Using Data Open  
Perform the procedure in Figure 3-8 to open a data file in preparation for recording  
measurement data to the memory card. This procedure is automatically invoked if the  
Q key is pressed and the instrument is configured for memory card operations. The  
instrument automatically assigns the next sequential dAtxx file name. To assign your  
own file name, use the up/down and left/right arrow keys when creating the file. When  
dAt99 is reached, the instrument loops back to reuse previously assigned file names that  
have been erased or skipped over. Data cannot be appended to an existing file, except in  
the case where scanning is turned off and on without changing the instrument  
configuration. Before using the DATA OPEN command, verify the instrument is  
configured for measurement. If a file is opened and then the instrument configuration is  
changed, the file will automatically be closed.  
Selecting the DATA mode. Press the FILES  
FILES  
Init  
StAt  
dir  
dAtA  
SEtUP  
FILES  
key to access the FILES menu. Press the  
up/down arrow keys until dAtA is displayed, then  
press the ENTER key. The menu changes to  
dAtA. If an error message appears, refer to  
Table 3-1.  
ENTER  
Selecting the OPEN mode. Press the up/down  
arrow keys until OPEn is displayed in the dAtA  
menu, then press the ENTER key. The menu  
changes to OPEn and a file name is displayed.  
dAtA  
ErASE  
OPEn  
ENTER  
Opening a dAtxx File. Record the displayed  
dAtxx file name, where xx represents an  
instrument-assigned number from 00 to 99. Or  
use the up/down, left/rightarrow keys to select the  
xx number. Press the ENTER key to open the  
file. If an error message appears, see Table 3-1.  
OPEn  
dAt99  
dAtxx  
dAt00  
The "dESt" menu appears if a dAtxx file is  
opened and the memory card is not selected as a  
data destination (see Figure 3-4).  
Typical  
Required  
ENTER  
op44f.eps  
Figure 3-8. Using DATA OPEN to Save Measurement Data in a File  
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Memory Card Operations  
Data File Procedures  
3
Using Data Erase  
Perform the procedure in Figure 3-9 to remove a data file from the memory card.  
Removing a file does not interrupt the sequential dAtxx file names assigned with the  
DATA OPEN command. When dAt99 is reached, the instrument will loop back and  
reuse previously assigned file names that have been erased or skipped over. To exit at  
any time (file not erased), press the C key.  
Selecting the DATA mode. Press the FILES key  
FILES  
Init  
StAt  
dir  
FILES  
to access the FILES menu. Press the up/down  
arrow keys until dAtA is displayed, then press the  
ENTER key. The menu changes to dAtA. If an  
error message appears, see Table 3-1.  
dAtA  
SEtUP  
ENTER  
Selecting the ERASE mode.  
Press the  
dAtA  
up/down arrow keys until ERASE is displayed in  
the dAtA menu, then press the ENTER key. The  
menu changes to ErASE.  
ErASE  
OPEn  
ENTER  
Selecting a dAtxx File to ERASE. Press the  
up/down arrow keys until the dAtxx file to be  
erased is displayed in the ErASE menu, where xx  
represents a number from 00 to 99, then press  
the ENTER key. The menu changes to SUrE.  
ErASE  
dAt99  
dAtxx  
dAt00  
ENTER  
Erasing a dAtxx File. Press the up/down arrow  
keys to select yES or no in the SUrE menu, then  
press the ENTER key. yES will erase the file; no  
will cancel the procedure and nothing will be  
erased. The procedure repeats after pressing  
ENTER, or displays nonE if there are no files to  
erase. Press the CANCL key to exit. If an error  
message occurs, see Table 3-1.  
SUrE  
yES  
no  
Typical  
Required  
ENTER  
op45f.eps  
Figure 3-9. Using DATA ERASE to Delete a Measurement Data File  
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2635A  
Users Manual  
Setup and Data Files Directory  
Perform the procedure in Figure 3-10 to obtain a directory of existing SEtxx files and  
dAtxx files that exist on the memory card, plus the remaining capacity of the card. The  
size of the selected file is given in the front panel display in K-bytes. To exit at any time  
(directory not completed), press the C key.  
Selecting the DIRECTORY mode. Press the  
FILES  
Init  
StAt  
dir  
FILES  
FILES key to access the FILES menu. Press the  
up/down arrow keys until dir is displayed, then  
press the ENTER key. The menu changes to  
nnnnK, where nnnn represents a number of  
kilobytes. If an error message appears, see  
Table 3-1.  
dAtA  
SEtUP  
Viewing the Available Memory Card Capacity.  
The bytes available on the memory card are  
displayed first as an overall directory summary.  
nnnnK  
FrEE  
ENTER  
Viewing the files. To view the size of the  
individual files, press the up/down arrow keys  
until the desired SEtxx or dAtxx file is displayed,  
where xx presents the file identification number  
from 00 to 99. The size of the selected file, in  
nnnnK  
SEt99  
SEtxx  
SEt00  
dAt99  
dAtxx  
dAt00  
kilobytes, is displayed.  
When directory  
operations are complete, press the ENTER key.  
ENTER  
Typical  
Required  
op46f.eps  
Figure 3-10. Using DIRECTORY to Examine SETUP and DATA files  
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Memory Card Operations  
Setup and Data File Current Status  
3
Setup and Data File Current Status  
Perform the procedure in Figure 3-11 to display the status of the memory card SEtxx and  
dAtxx files that are currently in effect or were in effect for the most recent scan. The xx  
portion of the file name represents a file identification number from 00 to 99.  
Selecting the STATUS mode. Press the FILES  
FILES  
Init  
StAt  
dir  
FILES  
key to access the FILES menu. Press the  
up/down arrow keys until StAt is displayed, then  
press the ENTER key.  
dAtA  
SEtUP  
ENTER  
Status of the Memory Card. The percent of the  
capacity of the memory card that has been used  
is shown, where nn represents a number from 00  
to 99. If no memory card is installed, the display  
is --Pct.  
USEd  
nnPct  
Status of the SEtxx File. The setup file that was  
in effect for the most recent scan is shown, where  
xx represents a file number from 00 to 99. If no  
setup file was open, nonE is displayed.  
ENTER  
SEtUP  
SEtxx  
-or-  
nonE  
Status of the dAtxx File. The data file that was  
open for the most recent scan is shown, where xx  
represents a file number from 00 to 99. If no data  
file was open, nonE is displayed.  
dAtA  
dAtxx  
-or-  
nonE  
Typical  
Required  
op47f.eps  
Figure 3-11. Using STATUS to Examine SETUP and DATA Files  
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2635A  
Users Manual  
Memory Card File Operations to and from a PC  
All memory card file transfers to and from the instrument are controlled at the PC.  
Nothing is required at the instrument end, except to have the RS-232 link operating  
correctly (see Chapter4, "Computer Operations") and having the desired memory card  
installed in the instrument front panel. Refer to the applications software documentation  
supplied with Starter (supplied) or Logger (optional).  
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Chapter 4  
Computer Operations  
Title  
Page  
Summary of Computer Operations.................................................................... 4-3  
Connecting the Instrument to a PC.................................................................... 4-3  
Configuring the Instrument for Computer Operations...................................... 4-5  
Configuring the PC for Computer Operations .................................................. 4-6  
Testing the Instrument/PC RS-232 Interface .................................................... 4-6  
Testing the RS-232 Interface Using Terminal Emulation (Windows) ......... 4-6  
Testing the RS-232 Interface Using Terminal Emulation (Generic) ............ 4-7  
Testing the RS-232 Interface Using Gwbasic............................................... 4-9  
Testing the RS-232 Interface Using Qbasic.................................................. 4-10  
Computer Interface Commands and Operation................................................. 4-12  
How the Instrument Processes Input............................................................. 4-12  
Input Terminators.......................................................................................... 4-12  
Input String Examples................................................................................... 4-13  
Sending Numeric Values to the Instrument .................................................. 4-13  
How the Instrument Processes Output.......................................................... 4-13  
Status Registers............................................................................................. 4-14  
Instrument Event Register (IER) .............................................................. 4-14  
Standard Event Status Register (ESR)...................................................... 4-16  
Status Byte Register (STB)....................................................................... 4-17  
Computer Interface Command Set................................................................ 4-18  
Xmodem File Transfers ................................................................................ 4-18  
4-1  
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2635A  
Users Manual  
DATA BUCKET  
REVIEW  
LAST  
HYDRA  
CH  
mA  
mVDCAC  
Hz  
M
k
V
COM  
REVIEW  
CLEAR  
FILES  
MODE  
INTVL  
SCAN  
CLOCK  
ALRM  
FUNC  
Mx+B  
SINGLE  
300V  
MAX  
RATE  
MON  
TOTAL  
ZERO  
ENTER  
LIST  
SHIFT  
CANCEL  
TRIGS  
COMM  
LOCAL  
BATT  
BUSY  
op82f.eps  
4-2  
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Computer Operations  
Summary of Computer Operations  
4
Summary of Computer Operations  
Computer operations allow the instrument to be configured and controlled from a  
personal computer (PC), including data exchanges with the instrument memory card.  
The computer interface is via an RS-232 link between the instrument RS-232 port and a  
PC serial COM port. The PC gives operation and configuration commands to the  
instrument, and the instrument returns status signals (alarms, for example) and scan  
measurement data. PC operations can be in real time with a dedicated RS-232  
connection, or the instrument can be connected to a PC for configuration and then  
removed for distant operations. Memory Card features are described in Chapter 3,  
Memory Card Operations.  
PC applications software Hydra Series II Starter Package (Starter) and Hydra Series II  
Logger Package (Logger) (optional) operate the RS-232 computer interface. The  
software packages are described in separate technical manuals; however, each  
accomplishes the following:  
Starter (supplied) Starter is a menu-driven software package used to transfer  
configuration data from and to the instrument, log measurement data  
collected by the instrument, and manage the acquired data.  
Logger (optional) Hydra Series II Logger is an optional full featured Windows based  
configuration  
and data logging package. It can communicate with two Hydras at  
once and can also utilize telephone modems for remote  
applications. A brochure with complete details is available.  
Custom software can be developed by the user in GWBASIC, Quick BASIC (QBASIC),  
or Quick C using the computer interface command set, which is described in this  
chapter.  
The RS-232 computer interface between a instrument and a PC is discussed in the  
following paragraphs in this sequence:  
Connecting the Instrument to a PC  
Configuring the Instrument for Computer Operations  
Configuring the PC for Computer Operations  
Testing the Instrument/PC RS-232 Interface  
Computer Interface Commands and Operation  
Connecting the Instrument to a PC  
The two most common configurations for connecting the instrument to a PC are shown  
in Figure 4-1. The instrument RS-232 port (DB-9 connector) is cabled to a PC serial  
COM port that uses either a DB-9 connector or DB-25 connector. The connecting cable  
can be fabricated (see Appendix D) or ordered from Fluke as an option (see Chapter 1).  
4-3  
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2635A  
Users Manual  
PC  
PC CONNECTION  
WITH DB-9  
CONNECTOR  
HYDRA  
RS-232  
(DB-9)  
(MALE)  
COM PORT  
(DB-9)  
(MALE)  
FLUKE R543 CABLE  
(OR EQUAL)  
PC  
PC CONNECTION  
WITH DB-25  
CONNECTOR  
HYDRA  
RS-232  
(DB-9)  
FLUKE RS40 CABLE  
(OR EQUAL)  
COM PORT  
(DB-25)  
(MALE)  
(MALE)  
op48f.eps  
Figure 4-1. Connecting the Instrument to a PC  
4-4  
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Computer Operations  
Configuring the Instrument for Computer Operations  
4
Configuring the Instrument for Computer Operations  
Correct operation of the interface between the instrument and PC depends on the baud  
rate, parity, CTS (Clear To Send) and echo of the RS-232 interface parameters. Perform  
the procedure in Figure 4-2 to establish these parameters for the instrument. The  
instrument uses one stop bit, which is not selectable.  
SHIFT  
Selecting the bAUd (Baud) Rate. Press the  
SHIFT key, release, and then press the LIST key  
bAUd  
LIST  
to open the communications parameters menu.  
The baud rate sets the rate of data transfer  
between the instrument and the PC. Normally,  
the highest compatible rate is selected. Select  
the rate using the up/down arrow keys, then  
press ENTER.  
38400  
19200  
9600  
4800  
2400  
1200  
600  
300  
ENTER  
ENTER  
ENTER  
ENTER  
Selecting PAR (Parity).  
The 8th bit of a  
PAR  
character can be set to make all characters odd  
(Odd) or even (E), or no parity at all (no). The  
computer checks parity (if selected) and indicates  
when an error is detected. Select the parity then  
press ENTER.  
no  
E
Odd  
Selecting CtS (Clear To Send). The RS-232  
CTS line (pin 8) is an input hardware control line  
derived from the PC Request to Send (RTS) line.  
When CTS is asserted, the instrument is allowed  
CtS  
On  
OFF  
to transmit data.  
If the PC RS-232 interface  
does not have or use an RTS line, select OFF  
then press ENTER.  
Selecting Echo.  
character sent to the instrument is "echoed" back  
to the PC. The applications software Starter  
When echo is On, each  
Echo  
On  
OFF  
and Logger automatically turn echo OFF. The  
primary use of Echo On is for operations with a  
terminal emulator. Select the Echo parameter  
then press ENTER.  
Typical  
Required  
op49f.eps  
Figure 4-2. Configuring the Instrument for Computer Operations  
4-5  
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2635A  
Users Manual  
Configuring the PC for Computer Operations  
Operation of the instrument from a PC always involves software, either software  
supplied with the instrument (Starter) or software developed by the user (GWBASIC,  
QBASIC or Quick C). Since the PC COM port is set up by the operating software, there  
is no separate configuration procedure.  
Testing the Instrument/PC RS-232 Interface  
The RS-232 link between the instrument and PC should be tested before it is used for  
communications. Since DOS commands cannot test the link, some form of software  
control is required. Four procedures are provided:  
Testing using terminal emulation (Windows)  
Testing using terminal emulation (Generic)  
Testing using commands while in GWBASIC  
Testing using commands while in QBASIC  
The RS-232 computer interface can also be tested using the TERM (Terminal) mode in  
both Starter and Logger applications software. Refer to the technical manuals supplied  
with the software for the test procedures.  
Testing the RS-232 Interface Using Terminal Emulation (Windows)  
Complete the procedure below to test the RS-232 link between the PC and instrument  
using the PC Windows terminal emulator. Identify the PC COM port used for the RS-  
232 link (COM1 is assumed).  
1. Configure the Data Bucket communication parameters, as described in Figure 4-2,  
for bAUd = 9600, PAR = no, CtS = OFF, and Echo = On.  
2. Turn on the PC, start Windows, open the Accessories menu and select Terminal.  
3. Open the Terminal Settings menu and select Communications.  
4. In Communications, select the following, then use OK to exit to Terminal:  
Connector COM1 [Typical]  
Baud Rate 9600  
Data Bits 8  
Stop Bits 1  
Parity None  
Flow ControlNone  
5. In Terminal, request the Data Bucket to send its identification number by entering:  
*IDN? <Enter>. If *IDN? did not appear on the screen as the characters were  
entered, be sure the instrument RS-232 port is configured for Echo = On (Figure 4-  
2). If the wrong characters appear, there is an incompatibility in the COM port  
configurations (baud rate, parity, etc.). If everything seems normal, but characters  
still dont appear, check the RS-232 connection cable (see Appendix D). When the  
RS-232 link is operating correctly, the instrument returns an identification string and  
execution prompt similar to the following:  
FLUKE,2635A,0,Mn.n An.n Dn.n Ln.n  
=>  
4-6  
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Computer Operations  
Testing the Instrument/PC RS-232 Interface  
4
Mn.n identifies the main software version.  
An.n identifies the analog-to-digital converter software version.  
Dn.n identifies the display software version.  
Ln.n identifies the programmable gate-array configuration version.  
6. Other commands can be entered from the PC to gain familiarity with the instrument  
command set. All commands are summarized in Table 4-4 and explained in Table 4-  
5.  
For example: to reset the instrument, configure channel 0 to measure volts dc using  
the 300V DC scale (scale 4), send scan results to the RS-232 port, and scan once,  
enter the following:  
*RST[Resets the instrument (which does not affect the communication parameters)]  
=>  
FUNC 0, VDC, 4[Set channel 0 to volts dc and scale 4 (300V DC)]  
=>  
PRINT_TYPE 0,0[Sets the data destination as the RS-232 port, and all data]  
=>  
PRINT 1[Enables data logging to the RS-232 port]  
=>  
*TRG [Triggers a single scan]  
=>  
15:17:0407/21/94  
0:000.00 VDC  
ALM:15DIO:255TOTAL:0  
To decode the printout, see Figure 5-3.  
The commands in the above example can be combined into a single entry by using  
the semicolon separator character:  
*RST;FUNC 0,VDC,4;PRINT_TYPE 0,0;PRINT 1;*TRG.  
7. One of the following three possible prompts are returned when a command is sent to  
the instrument:  
=> The command was executed[Example, PRINT 1].  
!> The command was recognized, but not executed [Example, PRINT 3, where only  
PRINT 0 and PRINT 1 are legal entries].  
?> The command wasnt recognized [Example, PRITN 1, spelling error].  
8. Exit Windows and return to DOS, as required.  
Testing the RS-232 Interface Using Terminal Emulation (Generic)  
Complete the procedure below to test the RS-232 link between the PC and instrument  
using a generic terminal emulator. Refer to the documentation appropriate to the selected  
communications/terminal emulation software, as required. Identify the PC COM port  
used for the RS-232 link (COM1 is assumed).  
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2635A  
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1. Configure the Data Bucket communication parameters, as described in Figure 4-2,  
for bAUd = 9600, PAR = no, CtS = OFF, and Echo = On.  
2. Turn on the PC, start the communications software, and open the COM port  
configuration screen.  
3. Select the following communications parameters  
Connector COM1 [Typical]  
Baud Rate 9600  
Data Bits 8  
Stop Bits 1  
Parity None  
Flow ControlNone[May be called the RTS/CTS line]  
4. In Terminal, request the Data Bucket to send its identification number by entering:  
*IDN? <Enter>. If *IDN? did not appear on the screen as the characters were  
entered, be sure the instrument RS-232 port is configured for Echo = On (Figure 4-  
2). If the wrong characters appear, there is an incompatibility in the COM port  
configurations (baud rate, parity, etc.). If everything seems normal, but characters  
still dont appear, check the RS-232 connection cable (see Appendix D). When the  
RS-232 link is operating correctly, the instrument returns an identification string and  
execution prompt similar to the following:  
FLUKE,2635A,0,Mn.n An.n Dn.n Ln.n  
=>  
Mn.n identifies the main software version.  
An.n identifies the analog-to-digital converter software version.  
Dn.n identifies the display software version.  
Ln.n identifies the programmable gate-array configuration version.  
5. Other commands can be entered from the PC to gain familiarity with the instrument  
command set. All commands are summarized in Table 4-4 and explained in Table 4-  
5.  
For example: to reset the instrument, configure channel 0 to measure volts dc using  
the 300V DC scale (scale 4), send scan results to the RS-232 port, and scan once,  
enter the following:  
*RST [Resets the instrument (which does not affect the communication parameters)]  
=>  
FUNC 0, VDC, 4 [Set channel 0 to volts dc and scale 4 (300V DC)]  
=>  
PRINT_TYPE 0,0 [Sets the data destination as the RS-232 port, and all data]  
=>  
PRINT 1 [Enables data logging to the RS-232 port]*TRG [Triggers a single scan]  
=>  
15:17:04 07/21/94  
0: 000.00 VDC  
4-8  
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Computer Operations  
Testing the Instrument/PC RS-232 Interface  
4
ALM:15 DIO:255 TOTAL:0  
To decode the printout, see Figure 5-3.  
The commands in the above example can be combined into a single entry by using  
the semicolon separator character:  
*RST;FUNC 0,VDC,4;PRINT_TYPE 0,0;PRINT 1;*TRG.  
6. One of the following three possible prompts are returned when a command is sent to  
the instrument:  
=>  
!>  
The command was executed [Example, PRINT 1].  
The command was recognized, but not executed [Example, PRINT 3, where  
only PRINT 0 and PRINT 1 are legal entries].  
?>  
The command wasnt recognized [Example, PRITN 1, spelling error].  
7. Exit the communications program and return to DOS, as required.  
Testing the RS-232 Interface Using Gwbasic  
Complete the procedure below to test the RS-232 link between the PC and instrument  
using GWBASIC interpreter commands. Identify the PC COM port used for the RS-232  
link (COM1 is assumed).  
1. Configure the Data Bucket communication parameters, as described in Figure 4-2,  
for bAUd = 9600, PAR = no, CtS = OFF, and Echo = On.  
2. Turn on the PC and enter GWBASIC to start the BASIC interpreter.  
3. With the entry screen displayed, enter the following commands (which are executed  
immediately). The last command returns an identification string and execution  
prompt:  
OPEN "COM1,9600,N,8,1,CS,CD" FOR RANDOM AS #1  
OK  
PRINT #1, "*IDN?"  
OK  
PRINT INPUT$ (46, #1)  
IDN?  
FLUKE,2635A,0,Mn.n An.n Dn.n Ln.n  
=>  
Mn.n identifies the main software version.  
An.n identifies the analog-to-digital converter software version.  
Dn.n identifies the display software version.  
Ln.n identifies the programmable gate-array configuration version.  
If the identification string was not returned, be sure the instrument RS-232 port is  
configured for Echo = On (Figure 4-2). Verify that the commands were exact. For  
example, entering PRINT #1, "*IDN" instead of PRINT #1, "*IDN?" will hang up  
the program. Press <CNTL><BREAK> to escape, then re-enter the commands. If  
the wrong characters appear, there is an incompatibility in the COM port  
configurations (baud rate, parity, etc.). If everything seems normal, but characters  
still dont appear, check the RS-232 connection cable (see Appendix D).  
4-9  
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2635A  
Users Manual  
One of the following three possible prompts are returned when a command is sent to  
the instrument:  
=>  
!>  
The command was executed [Example, PRINT 1].  
The command was recognized, but not executed [Example, PRINT 3,  
where only PRINT 0 and PRINT 1 are legal entries].  
?>  
The command wasnt recognized [Example, PRITN 1, spelling error].  
4. Other commands can be entered from the PC to gain familiarity with the instrument  
command set. All commands are summarized in Table 4-4 and explained in Table 4-  
5. For example: to reset the instrument, configure channel 0 to measure volts dc  
using the 300V DC scale (scale 4), send scan results to the RS-232 port, and scan  
once, enter the following [only the output of the last command is shown]:  
PRINT #1, "*RST":PRINT INPUT$(10, #1)  
PRINT #1, "FUNC 0, VDC,4":PRINT INPUT$(18, #1)  
PRINT #1, "PRINT_TYPE 0,0":PRINT INPUT$(20, #1)  
PRINT #1, "PRINT 1":PRINT INPUT$(13, #1)  
PRINT #1, "*TRG":PRINT INPUT$(83, #1)  
15:17:0407/21/94  
0:000.00 VDC  
ALM:15DIO:255TOTAL:0  
To decode the printout, see Figure 5-3.  
The commands in the above example can be combined into a single entry by using  
the semicolon separator character:  
PRINT #1, "*RST;FUNC 0,VDC,4;PRINT_TYPE 0,0;PRINT 1;*TRG":PRINT  
INPUT$(124, #1)  
If other commands are entered, remember that the input character count xxx for  
PRINT INPUT$(xxx, #1) command must be exact. A number too small will not read  
all the characters and will leave residual characters in the buffer, while a number too  
big will "hang up" the command until more characters are loaded into the buffer or  
<CNTL><BREAK> is pressed, which erases the buffer.  
5. Enter SYSTEM to exit GWBASIC and return to DOS.  
Testing the RS-232 Interface Using Qbasic  
Complete the procedure below to test the RS-232 link between the PC and instrument  
using QBASIC compiler commands. Identify the PC COM port used for the RS-232 link  
(COM1 is assumed).  
1. Configure the Data Bucket communication parameters, as described in Figure 4-2,  
for bAUd = 9600, PAR = no, CtS = OFF, and Echo = On.  
2. Turn on the PC and enter QBASIC to start the BASIC compiler.  
3. With the entry screen displayed, enter the following commands (which are not  
executed immediately):  
OPEN "COM1,9600,N,8,1,CS,CD" FOR RANDOM AS #1  
PRINT #1, "*IDN?"  
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Computer Operations  
Testing the Instrument/PC RS-232 Interface  
4
PRINT INPUT$(46, #1)  
4. Enter SHIFT<F5> to run the program entered in step 3.If the RS-232 interface is  
operating correctly, the instrument returns an identification string and execution  
prompt similar to the following:  
*IDN?  
FLUKE,2635A,0,Mn.n An.n Dn.n Ln.n  
=>  
Mn.n identifies the main software version.  
An.n identifies the analog-to-digital converter software version.  
Dn.n identifies the display software version.  
Ln.n identifies the programmable gate-array configuration version.  
If the identification string was not returned, be sure the instrument RS-232 port is  
configured for Echo = On (Figure 4-2). Verify that the commands were exact. For  
example, entering PRINT #1, "*IDN" instead of PRINT #1, "*IDN?" will hang up  
the program. Press <CNTL><BREAK> to escape, then re-enter the commands. If  
the wrong characters appear, there is an incompatibility in the COM port  
configurations (baud rate, parity, etc.). If everything seems normal, but characters  
still dont appear, check the RS-232 connection cable (see Appendix D).  
One of the following three possible prompts are returned when a command is sent to  
the instrument:  
=>  
!>  
The command was executed [Example, PRINT 1].  
The command was recognized, but not executed [Example, PRINT 3,  
where only PRINT 0 and PRINT 1 are legal entries].  
?> The command wasnt recognized [Example, PRITN 1, spelling error].  
5. Other commands can be entered from the PC to gain familiarity with the instrument  
command set. All commands are summarized in Table 4-4 and explained in Table 4-  
5. For example: to reset the instrument, configure channel 0 to measure volts dc  
using the 300V DC scale (scale 4), send scan results to the RS-232 port, and scan  
once, enter the following, then enter SHIFT<F5> to run [only the output of the last  
command is shown]:  
PRINT #1, "*RST":PRINT INPUT$(10, #1)  
PRINT #1, "FUNC 0, VDC,4":PRINT INPUT$(18, #1)  
PRINT #1, "PRINT_TYPE 0,0":PRINT INPUT$(20, #1)  
PRINT #1, "PRINT 1":PRINT INPUT$(13, #1)  
PRINT #1, "*TRG":PRINT INPUT$(83, #1)  
15:17:0407/21/94  
0:000.00 VDC  
ALM:15DIO:255TOTAL:0  
To decode the printout, see Figure 5-3.  
The commands in the above example can be combined into a single entry by using  
the semicolon separator character:  
4-11  
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2635A  
Users Manual  
PRINT #1, "*RST;FUNC 0,VDC,4;PRINT_TYPE 0,0;PRINT 1;*TRG":PRINT  
INPUT$(124, #1)  
If other commands are entered, remember that the input character count xxxfor  
PRINT INPUT$(xxx, #1)command must be exact. A number too small will  
not read all the characters and will leave residual characters in the buffer, while a  
number too big will "hang up" the command until more characters are loaded into  
the buffer or <CNTL><BREAK> is pressed, which erases the buffer.  
6. Use Exit to exit QBASIC and return to DOS.  
Computer Interface Commands and Operation  
Operation of the computer interface between the instrument and PC normally involves  
the application software Starter (supplied) and Logger (optional), described in separate  
manuals. This chapter is provided for the user who wishes to develop his own software  
interface using the instrument command set. The topics in this chapter include:  
How the Instrument Processes Input  
Input Terminators  
Input String Examples  
Sending Numeric Values to the instrument  
How the Instrument Processes Output  
Status Registers  
Computer Interface Command Set  
How the Instrument Processes Input  
The instrument processes and executes valid input character strings from the host  
personal computer (PC). A valid input string is one or more syntactically correct  
commands, separated by semicolons (;) followed by an input terminator. The instrument  
stores received inputs in a 350-byte buffer. When an input string is received, it is not  
executed or checked for proper syntax until the input terminator is received. If the 350-  
byte input buffer becomes full, a device-dependent error prompt is returned, and further  
inputs to the string are ignored, except for a termination character. The instrument  
accepts alphabetic characters in either upper- or lower-case. If a command cannot be  
understood, the command and the rest of the command line are ignored.  
Commands must be entered in the correct order as follows:  
1. Commands to configure the instrument.  
2. Commands that trigger a measurement.  
3. Commands to read the results of a triggered measurement.  
4. Commands to reconfigure the instrument (if any).  
Input Terminators  
An input terminator is a character sent by the host that identifies the end of a string.  
When the input terminator is received, the instrument executes all commands entered  
since the last terminator was received, on a first-in, first-out basis. If a communications  
error (e.g., parity, framing, overrun) is detected, a device-dependent error is generated.  
Valid terminators are LF (line feed), CR (carriage return), CR LF, and LF CR. In some  
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Computer Operations  
Computer Interface Commands and Operation  
4
instances, a terminator is automatically transmitted by the host at the end of the  
command string, for example, commands entered in BASIC.  
Input String Examples  
Below are four input string examples. Example 1 - Select function for channel 1 as  
ohms, 30-k range, 2-wire connection.  
FUNC 1, OHMS, 3, 2 <CR/LF>  
Example 2 - Select function for channel 12 as temperature, using K-type thermocouple.  
FUNC 12, TEMP, K <CR/LF>  
Example 3 - Select function for channel 7 as temperature, using platinum RTD, 2-wire  
connection -and- set a new R0 [0 as in zero] value on the same channel of 101.22.  
FUNC 7, TEMP, PT, 2;RTD_R0 7, 101.22 <CR/LF>  
Example 4 - Set the interval between scans to 10 minutes -and- start scanning -and-  
return the most recent measurement values for all scanned channels.  
INTVL 0, 10, 0;SCAN 1;LAST? <CR/LF>  
Sending Numeric Values to the Instrument  
Numeric values can be sent to the instrument as integers, real numbers, or real numbers  
with exponents, as shown in the following examples:  
+12345Sends the signed integer+12345  
123.45Sends the real number123.45  
1.2345E+2Sends the number -1.2345 x 102  
How the Instrument Processes Output  
The instrument outputs alphanumeric character strings in response to a query command  
from the host. A query command always ends with "?" (see Tables 4-4 and 4-5). An  
instrument output string is terminated by a CR/LF (carriage return/line feed). When the  
host sends a string to the instrument, wait for the instrument to return a prompt before  
sending another command string. If a second command is sent before the prompt is  
returned, a device-dependent command error (!>) is generated and the second string is  
ignored. The prompts are in one of three forms:  
=>  
The command was executed.  
[Example, PRINT 1]  
!>  
The command was recognized but couldnt be executed.  
[Example, PRINT 3, which has no meaning]  
?> The command was not recognized due to syntax error.  
[Example, PRITN 1, spelling error]  
Numeric outputs from the instrument are either integer values or scientific notation  
values. For example:  
The query command RANGE? returns the number 3.  
The query command ALARMS? returns the number 0.  
A measurement returns +1.2345E+6 (1.2345x106).  
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2635A  
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Positive overload (OL on display) returns +001.00E+9  
Negative overload (-OL on display) returns -001.00E+9  
Open thermocouple (otc on display) returns +009.00E+9  
Status Registers  
Internal instrument operation is summarized in three data registers, which can be  
accessed to determine various events and status conditions before, during, and after  
instrument operation. Each register has a corresponding enable register to enable or  
mask (disable) any or all data register outputs. The relationship between the three  
registers is shown in Figure 4-3.  
Instrument Event Register (IER)  
The inputs to the Instrument Event Register (IER) include Scan Complete, Configuration  
Corrupted, Calibration Corrupted, Open Thermocouple, Totalize Overflow, and Alarm  
Limit Transition. Each input is described in Table 4-1. The output byte of the IER is  
ANDed with the output byte of the corresponding Instrument Event Enable Register  
(IEE). When there is logic high correlation between any of the bits of the IER and IEE  
registers, the associated Logical OR gate will output a logic high to the Instrument Event  
Bit (IEB) in the Status Byte Register.  
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Computer Operations  
Computer Interface Commands and Operation  
4
Scan Complete  
CofigurationCaCloibrrautpiotendOCpoerrnupTtheedrmTotcaoliuzpeleOvAelraflromwLimit Transition  
Device Dependent Error  
Query Error  
OperationSCotmapnletde ard  
Event Status  
Register  
Read Using *ESR?  
(Read Erases  
Contents)  
Power Transition  
Execution Error  
Command Error  
Instrument  
Event  
Register  
6
2
7
5 4 3  
1
0
6
2
7
5 4 3  
1
0
Read Using IER?  
(Read Erases  
Contents)  
&
&
&
&
&
&
&
&
&
&
&
2
&
2
&
1
&
1
&
0
&
0
Standard  
Event Status  
Enable  
Instrument  
Event Enable  
Register  
6
7
5 4 3  
6
7
5 4 3  
Register  
Read Using IEE?  
Write Using IEEE  
Read Using *ESE?  
Write Using *ESE  
Queue  
Not-Empty  
Output Queue  
MSS ESB MAV IEB  
*STB  
(64) (32) (16)  
(1)  
(DECIMAL)  
Status Byte  
Register  
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
IEB  
MAV  
MSS ESB  
2
7
3
1
16  
17  
32  
33  
48  
49  
64  
65  
80  
81  
96  
97  
112  
113  
Read Using *STB?  
&
&
&
&
&
2
&
1
&
0
Service Request  
Enable Register  
Read Using *SRE?  
Write Using *SRE  
7
5 4 3  
op50f.eps  
Figure 4-3. Overview of Status and Event Data Registers  
4-15  
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2635A  
Users Manual  
For example, an IER byte of binary 10000000 (decimal 128) indicates Scan Complete. If  
the IEE register is set to binary 10000000 (using the command IEE 128), then a Scan  
Complete condition will cause the Logical OR gate to output a logic high. In a similar  
manner, parameters can be combined. An IER byte of binary 10000101 (decimal 133)  
and an IEE set to a corresponding binary 10000101 (using the command IEE 133), will  
cause the Logical OR gate to have a logic high output for any of three conditions: Scan  
Complete -or- Open Thermocouple -or- Alarm Limit Transition.  
Other commands include IER?, which returns the decimal equivalent of the IER byte and  
then clears the register to zero, and IEE?, which returns the decimal equivalent of the  
IEE byte. The command *CLS will clear all event registers. (See Appendix E for an 8-bit  
binary-coded-decimal table.)  
Table 4-1. Instrument Event Register (IER)  
Bit  
Name  
ALT  
Description  
0
1
Alarm Limit Transition. Set high (1) when any measurement value has  
transitioned into or out of alarm. Alarms are defined through the front  
panel or the computer interface (ALARM_LIMIT). This bit is cleared when  
read with IER? and when alarms or review values are cleared.  
TOB  
Totalize Overflow. Set high (1) when the Totalizer overflows (65,535). This  
bit is cleared when read with IER? and when the Totalizer is zeroed from  
the front panel or set to some other non-overflow value (,65,535) with the  
computer interface TOTAL command.  
2
3
OTC  
CCB  
Open Thermocouple. Set high (1) when open thermocouple checking is  
enabled (with TEMP_CONFIG command) and any thermocouple channel  
is measured with a source impedance greater than 1 to 4 kilohms.  
Calibration Corrupted. Set high (1) when the instrument calibration data is  
corrupted. When a calibration data check shows a corruption of calibration  
data, the calibration alarm bit remains set in the Instrument Status  
Register until the instrument is recalibrated.  
4
CNC  
Configuration Corrupted. the instrument configuration stored in NVRAM  
has been found to be corrupted. The RAM CRC is no longer valid.  
5,6  
7
not used  
SCB  
Always set to 0.  
Scan Complete. Set high (logic 1) when a measurement scan has been  
completed. This bit is cleared when read with IER?  
NOTES  
Whenever the Instrument Event Register is read, the condition bits are cleared.  
This register is used in conjunction with the Instrument Event Enable Register to determine the  
conditions under which the Instrument Event Bit of the Status Byte is set.  
Standard Event Status Register (ESR)  
The inputs to the Standard Event Status Register (ESR) include Power On, Command  
Error, Execution Error, Device Dependent Error, Query Error and Operation Complete.  
Each input is described in Table 4-2. The output byte of the ESR is ANDed with the  
output byte of the corresponding Standard Event Status Enable (ESE) register. When  
there is logic high correlation between any of the bits of the ESR and ESE registers, the  
4-16  
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4
associated Logical OR gate will output a logic high to the Event Status Bit (ESB) in the  
Status Byte Register.  
For example, an ESR byte of binary 00010000 (decimal 16) indicates an Execution  
Error. If the ESE register is set to binary 00010000 (using the command *ESE 16), then  
an Execution Error condition will cause the Logical OR gate to output a logic high. In a  
similar manner, parameters can be combined. An ESR byte of binary 00110000 (decimal  
48) and an ESE set to a corresponding binary 00110000 (using the command *ESE 48),  
will cause the Logical OR gate to have a logic high output for any of two conditions:  
Command Error or Execution Error.  
Other commands include *ESR?, which returns the decimal equivalent of the ESR byte  
and then clears the register to zero, and *ESE?, which returns the decimal equivalent of  
the ESE byte. The command *CLS will clear all event registers. (See Appendix E for an  
8-bit binary-coded decimal table.)  
Table 4-2. Event Status Register (ESR)  
Bit  
Name  
Description  
0
OPC  
Operation Complete. set true (1) upon execution of the *OPC  
command, indicating that the instrument has completed all selected  
pending operations  
1
2
not used  
QYE  
Always set to 0.  
Query Error. Sets the QYE bit of the ESR. Example would be *IDN?;  
*ESR? (vs. *ESR?; *IDN?). This causes the “?>“ prompt to be  
returned.  
3
4
DDE  
EXE  
Device Dependent Error. Generated true (1) by overflows of the RS-  
232 input buffer or by calibration errors. This causes the “!>“ prompt  
to be returned.  
Execution Error. Generated true (logic 1) by parameters out of  
bounds or by a valid command that could not be processed due to  
an internal condition (such as calibration commands being received  
when calibration is not enabled). This causes the “!>“ prompt to be  
returned.  
5
CME  
Generated true (1) by syntax errors, including: unrecognized  
command and incorrect command sequences. This causes the "?>"  
prompt to be returned.  
6
7
not used  
PON  
Always set to 0  
Power Transition. Set true (logic 1) after an off-to-on transition has  
occurred in the instrument’s power supply.  
Status Byte Register (STB)  
The inputs to the Status Byte Register (STB) include the Instrument Event Bit, Event  
Status Bit, and Message Available Bit. In addition, the STB register generates a Master  
Summary Status. Each input is described in Table 4-3. The output byte (except for bit 6)  
is ANDed with the output byte of the corresponding Service Request Enable Register  
(SRE). When there is a logic high correlation between any of the bits of the STB and  
SRE registers, the associated Logical OR gate will output a logic high that is used as a  
Master Summary Status (MSS) bit.  
4-17  
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For example, an STB byte of binary 00100000 (decimal 32) indicates an Event Status  
Bit. If the SRE register is set to binary 00100000 (using the command *SRE 32), then an  
Event Status Bit will cause the Logical OR gate to output a logic high, which  
automatically sets bit 6 to high via the MSS input. Therefore, a query of the STB register  
(command *STB?) would return decimal 96 (binary 01100000).  
Other commands include *SRE?, which returns the decimal equivalent of the SRE byte.  
The command *CLS will clear all event registers. (See Appendix E for an 8-bit binary-  
coded decimal table.)  
Table 4-3. Status Byte Register (STB)  
Bit  
Name  
IEB  
Description  
0
Instrument Event Bit. When any bit in the Instrument Event Register is set and  
the corresponding mask bit(s) in the Instrument Event Enable register is set,  
this Instrument Event Bit in the Status Byte will be set.  
When read, the Instrument Event Bit is recomputed based on the new value  
from the Instrument Event Register and its mask, the Instrument Event Enable  
Register.  
1,2,3  
not used  
MAV  
ESB  
MSS  
not used  
Always set to 0.  
Message Available (ASCII bytes available for output).  
Event Status Bit  
Master Summary Status  
Always set to 0.  
4
5
6
7
Computer Interface Command Set  
Table 4-4 is a summary of computer interface commands and queries. A detailed  
description of each command or query, with examples, can be found in Table 4-5.  
Sample programs that use the command set are shown in Figure 4-4 (GWBASIC),  
Figure 4-5 (QBASIC) and Figure 4-6 (Quick C). Program examples are provided on the  
Starter application software floppy disk.  
Xmodem File Transfers  
The FILE_TX and FILE_RX computer commands are used to transfer memory card files  
in binary format over the RS-232 interface. The protocol implemented for file transfers  
is XMODEM, an 8-bit block-oriented protocol using CRC or checksums for error  
checking. When receiving a file, the protocol attempts to do CRCs but will fall back to  
checksums if CRCs are not sent. When FILE_TX and FILE_RX are used with terminal  
emulators, the emulator must support the XMODEM protocol; for example, the PC  
Windows terminal emulator. The PC software must support both 128-byte and 1024-byte  
data blocks. Since XMODEM is an 8-bit protocol, no parity must be selected when  
configuring the RS-232 ports and XON/XOFF flow control cannot be used.  
When a FILE_TX or FILE_RX command is issued, it returns an immediate execution  
error prompt (!>) if the file transfer can not be initiated. If this prompt is not returned,  
then the XMODEM transfer may begin (refer to the communications software being  
used for the procedure to send or receive a binary file). When the file transfer is  
complete, the => prompt is returned. If an unrecoverable error occurred, the !> prompt is  
returned. As with any XMODEM transfer, the last block received, if it is not an even  
multiple of 128 or 1024 bytes, is padded with nulls. See the FILE_RX and FILE_TX  
commands in Table 4-5 for more information.  
4-18  
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4
Table 4-4. Command and Query Summary  
Alarms  
ALARMS?  
Active Alarms Query  
ALARM_ASSOC  
ALARM_ASSOC?  
ALARM_ASSOC_CLR  
ALARM_DO_LEVEL  
ALARM_DO_LEVELS?  
ALARM_LIMIT  
ALARM_LIMIT?  
Communications  
ECHO  
Associate Alarm Output  
Alarm Association Query  
Clear Alarm Association  
Set Alarm Output Level  
Alarm Output State Query  
Set Alarm Limit  
Alarm Limit Assignments Query  
Turn the RS-232 Echo Mode on and off  
Digital I/O  
DIO_LEVELS?  
DO_LEVEL  
Digital I/O State Query  
Set Digital Output Level  
Function and Range  
FUNC  
Channel Function Definition  
Channel Function Query  
RTD Ice Point (R0)  
FUNC?  
RTD_R0  
RTD_R0?  
RTD Ice-Point (R0) Query  
Channel Range Query  
RANGE?  
Logging  
LOG?  
Retrieve Logged Data Query  
Scan Data Query  
LOGGED?  
LOG_BIN?  
Binary Upload of Logged Data  
Clear Logged Scans  
LOG_CLR  
LOG_CLR1  
Clear Oldest Logged Scan  
Logged Scan Count Query  
Action when Internal Memory is Full  
Action when Internal Memory is Full Query  
Data Logging Enable/Disable  
Data Logging Query  
LOG_COUNT?  
LOG_MODE  
LOG_MODE?  
PRINT  
PRINT?  
PRINT_TYPE  
PRINT_TYPE?  
Set Data Logging Type  
Data Logging Type Query  
4-19  
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2635A  
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Table 4-4 Command and Query Summary (cont)  
Measurement Rate  
RATE  
Select Measurement Rate  
Measurement Rate Query  
RATE?  
Measurement Values  
LAST?  
Channel’s Last Scan Value  
Channel’s Maximum Value  
Channel’s Minimum Value  
Next Scan’s Values  
MAX?  
MIN?  
NEXT?  
Memory Card  
DIR  
Memory Card Files Directory  
File Error Query  
FILE_ERROR?  
FILE_LOAD  
FILE_OPEN  
FILE_OPEN?  
FILE_REMOVE  
FILE_RX  
Configuration File Load  
Data File Open  
Data File Open Query  
File Remove  
File Receive  
FILE_SPACE?  
FILE_STORE  
FILE_TAG?  
FILE_TX  
File Space Query  
Configuration File Store  
File Tag Query  
File Transmit  
MCARD?  
Memory Card Status Query  
Memory Card Directory Query  
Memory Card Format  
Memory Card Size Query  
MCARD_DIR?  
MCARD_FORMAT  
MCARD_SIZE?  
Monitor  
MON  
Enable/Disable Monitoring  
Monitor Channel Number  
Monitor Channel Value  
MON_CHAN?  
MON_VAL?  
Mx+B Scaling  
SCALE_MB  
SCALE_MB?  
Operation Complete  
*OPC  
Set Mx+B Scaling Values  
Mx+B Scaling Values Query  
Operation Complete  
*OPC?  
Operation Complete Query  
4-20  
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4
Table 4-4 Command and Query Summary (cont)  
Remote/Local  
LOCK  
Lock/unlock front panel control keys  
Returns instrument front panel lock status  
Local without Lockout  
LOCK?  
LOCS  
LWLS  
Local with Lockout  
REMS  
Remote without Lockout  
RWLS  
Remote with Lockout  
Reset  
*RST  
Reset  
Response Format  
FORMAT  
FORMAT?  
Review Array  
REVIEW_CLR  
Status Registers  
*CLS  
Response Format  
Query Response Format  
Clear Review Values  
Clear Status  
*ESE  
Event Status Enable  
*ESE?  
Event Status Enable Query  
Event Status Register Query  
Instrument Event Enable  
*ESR?  
IEEE  
IEEE?  
Instrument Event Enable Query  
Instrument Event Register Query  
Service Request Enable Register  
Service Request Enable Register Query  
Read Status Byte Query  
IER?  
*SRE  
*SRE?  
*STB?  
Scan  
INTVL  
Set Scan Interval  
INTVL?  
Scan Interval Query  
Enable/Disable Scanning  
Return Scan Status  
Time of Scan  
SCAN  
SCAN?  
SCAN_TIME?  
Temperature Options  
TEMP_CONFIG  
TEMP_CONFIG?  
Temperature Configuration  
Temperature Configuration Query  
4-21  
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Table 4-4 Command and Query Summary (cont)  
Test/Identification  
*IDN?  
Identification Query  
Selftest Query  
*TST?  
Time/Date  
DATE  
Set Instrument Date  
TIME  
Set the instrument Time  
Retrieve Time and Date  
TIME_DATE?  
Totalizer  
TOTAL  
Set Totalizer Count  
TOTAL?  
TOTAL_DBNC  
TOTAL_DBNC?  
Triggering  
*TRG  
Totalizer Value Query  
Set Totalizing Debounce  
Totalizer Debounce Query  
Single-Scan Trigger  
Select Trigger Type  
Trigger Type Query  
TRIGGER  
TRIGGER?  
Wait  
*WAI  
Wait-to-Continue  
4-22  
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4
Table 4-5. Command and Query Reference  
<CNTL><C>  
*CLS  
Abort Command  
Stops execution of command  
Clear Status  
Clears all event registers (ESR, (IER) summarized in the status byte.  
Event Status Enable  
*ESE  
Sets the Event Status Enable Register to the given value.  
*ESE <value>  
<value>  
=
(0 .. 255)  
The ESE register is used to enable or mask the output bits of the Standard  
Event Status Register (ESR). The ANDed output of the ESE and ESR is  
the Event Status Bit (ESB), which is used as an input for the Status Byte  
Register. See the previous discussion on status registers for more  
information.  
Example: *ESE 176 [Enables the ESR byte 10110000 (decimal 176),  
which means the ESB will be set logic high by a Power Transition -or-  
Command Error -or- Execution Error.]  
*ESE?  
Event Status Enable Query  
Returns an integer representing the present value of the Event Status  
Enable Register, as selected with the *ESE command. See the previous  
discussion on status registers for more information.  
Example: *ESE? returns 160 [the ESE register is set for 10100000  
(decimal 160), which means the Event Status Bit (ESB) will be set logic  
high by a Power Transition -or- Command Error]  
*ESR?  
Event Status Register Query  
Returns the value of the Standard Event Status Register (ESR) as an  
integer, then clears the register to 0. See the previous discussion on status  
registers for more information.  
Example: *ESR? returns 48 [The ESR register is set for 00110000  
(decimal 48), which means a Command Error and Execution Error were  
detected since last queried.]  
4-23  
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Table 4-5. Command and Query Reference (cont)  
*IDN?  
Identification Query  
Returns the instrument identification code.  
The identification code consists of four descriptive fields separated by  
commas. Note that commas are reserved as field separators and cannot  
be used within the fields.  
FIELD  
DESCRIPTION  
1
2
3
4
Manufacturer’s name (FLUKE).  
Instrument model number (2620A or 2625A).  
0
Firmware revision levels.  
This query must be the last query on the input line, otherwise a query error  
is generated. It is legal to follow this query with other commands.  
Example: *IDN? returns FLUKE, 2635A, 0, M6.E A4.7 D1.L1.6 {Fluke  
product 2645A is running the main software version M6.2, Analog-to-  
Digital Converter software version A4.7, display software version D1.0,  
and programmable gate-array version L1.6.]  
*OPC  
Operation Complete  
Causes the instrument to generate an Operation Complete when parsed.  
Operation Complete Query  
*OPC?  
Causes the instrument to place an ASCII 1 in the output queue when  
parsed.  
*RST  
Reset  
Performs a Configuration Reset. The RS-232 computer interface  
parameters are not changed, and the temperature unit (°C or °F) is not  
changed.  
*SRE  
Service Request Enable  
Sets the Service Request Enable Register to the given value.  
*SRE <value>  
<value> = (0 .. 255)  
The SRE register is used to enable or disable (mask) the output bits of the  
Status Byte Register (STB). The ORed output of the SRE and STB is the  
Master Summary Status (MSS) bit, which is used to signal the selected  
status bits have been set. See the previous discussion on status registers  
for more information. Note that bit 6 cannot be configured, and bits 1, 2, 3,  
and 7 are not used.  
Example: *SRE 49 [Enables the STB byte 00110001 (decimal 49), which  
means the MSS bit is set logic high by an IEB bit -r-MAV bit -or- ESB bit.]  
Service Request Enable Query  
*SRE?  
Returns the integer value of the Service Request Enable Register (SRE).  
See the discussion on status registers for more information.  
Example: *SRE? returns 32 [The SRE register is set for 00100000  
(decimal 32), which means the Master Summary Bit will be set logic high  
when the ESB bit is set logic high.]  
4-24  
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4
Table 4-5. Command and Query Reference (cont)  
*STB?  
Read Status Byte Query  
Returns the integer value of the Status Byte, with bit 6 as the master  
summary bit. See the previous discussion on status registers for more  
information.  
Example: *STB returns 97 [The STB register is set for 01100001  
(decimal 97), which means the Master Summary Bit, Even Status Bit, and  
instrument Even Bit are set logic high.]  
*TRG  
Single- Scan Trigger  
This command causes the instrument to perform a Single Scan. If a scan  
is already in progress when this command is parsed, the command is  
ignored.  
If logging to memory card is enabled (PRINT_TYPE 3 or 6) and the  
memory card is missing, full, write-protected, or unformatted, the scan will  
be performed but an Execution error will be generated.  
*TST?  
Self Test Query  
Causes an internal self test to be run, returning the result as an integer  
(representing the binary encoded value.) The self test does not require any  
local operator interaction and returns the instrument to the power-up state.  
The binary coding is:  
Bit  
Binary Value  
Error  
0
1
Boot ROM Checksum Error1  
1
2
2
4
Instrument ROM Checksum Error  
Internal RAM Test Failed  
3
4
8
16  
Display Power-Up Test Failed  
Display Bad or Not Installed  
5
6
7
8
32  
64  
Instrument Configuration Corrupted.  
Instrument Calibration Data Corrupted  
Instrument Not Calibrated  
A-to-D Converter Not Responding  
A-to-D Converter ROM Test Failed  
A-to-D Converter RAM Test Failed  
A-to-D Converter Self test Failed  
Memory Card Interface Not Installed  
128  
256  
512  
1024  
2048  
4096  
9
10  
11  
12  
Example: *TST? returns 2048 [The A/D self test failed.]  
Wait-to-continue  
*WAI  
Prevents the parser from executing any more commands or queries until  
the No-Pending-Operations flag is true. Used in conjunction with *OPC  
and *OPC?  
4-25  
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Users Manual  
Table 4-5. Command and Query Reference (cont)  
ALARMS?  
Active Alarms Query  
Returns alarm status for a single scanned channel, or alarm status for all  
scanned channels.  
ALARMS? <channel>  
<channel> = (0 .. 20) or leave blank  
The values returned represents data from the most recent scan, whether  
scanning is active or note. The integers returned indicated the alarms  
condition as follows:  
0
1
2
3
neither limit is in alarm and/or alarm(s) not defined  
Limit "1" in alarm  
Limit "2" in alarm  
Limit "1" and Limit "2" in alarm  
For a single scanned channel, use ALARMS? <channel>. Return data for  
a single scanned channel consists of a single integer, as defined above.  
An Execution Error results if a request is made for a channel defined as  
OFF, the channel specified is invalid, no scan measurements have been  
made or are being made, or values have been cleared by REVIEW_CLR  
or by changing any parameter on any channel.  
For all canned channels, use ALARMS?. Return data for all scanned  
channels is a string of integers, separated by commas. The first digit  
represents the alarm status of the lowest channel scanned, and the last  
digit represents the alarm status of the highest channel scanned.  
Example: ALARMS? 5 returns 1 [Channel 5 is in Limit 1alarm.]  
Example: ALARMS? returns 0,2,3,0,1,1, [Six channels were scanned. The  
first has no alarm or alarms were not defined, the second has a Limit 2  
alarm, the third has both Limit 1 and Limit 2 in alarm, the fourth has no  
alarm or alarms were not defined, the fifth and sixth have a Limit 1 alarm.]  
4-26  
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4
Table 4-5. Command and Query Reference (cont)  
ALARM_ASSOC  
Associate Alarm Output  
Configures alarm output associations at the rear panel DIGITAL I/O  
connector for channels 4 to 20.  
ALARM_ASSOC <channel>,<limit_num>,<DO_line>  
<channel>  
= (4 .. 20)  
<limit_num> = 1 or 2  
<DO_line> = (0 .. 7)  
This command is used to associate a channel alarm for channels 4 to 20  
with a rear panel DIGITAL I/O line (I/O 0 to I/O 7). Alarm conditions are  
asserted with a logical low (nominal =0.7V DC); non-alarm conditions are  
indicated by a logical high (nominal =5.0V DC). The default setting for 4 to  
20 are ORed to the I/O lines in groups, as shown below.  
I/O 4  
Chan  
4
I/O 5  
Chan  
5
I/O 6  
Chan  
6
I/O 7  
Chan  
7
8
9
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
For example, if channel 6 or 10 0r 14 0r 18 goes into alarm (either Limit 1  
or Limit 2), I/O 6 is asserted. This command changes the default settings  
or any other settings, as desired. Any number of channel alarm limits can  
be assigned to the same I/O line. For example, all alarms on all channels 4  
to 20 could assert a single I/O line. Alarm associations can be returned to  
the default settings with an *RST configuration reset command. DIGITAL  
I/O lines set logic low remain low unless values have been cleared by a  
new alarm association, REVIEW_CLR, or by changing any parameter on  
any channel. If this command is entered during scanning while logging to  
the memory card, an Execution Error is generated.  
Example: ALARM_ASSOC 10,1,2 [For channel 10, alarm Limit 1, assert  
DIGITAL I/O line 2].  
4-27  
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2635A  
Users Manual  
Table 4-5. Command and Query Reference (cont)  
ALARM_ASSOC?  
Alarm Association Query  
Returns alarm output associations at the rear panel DIGITAL I/O connector  
for channels 4 to 20.  
ALARM_ASSOC?  
<channel>,<limit_num>  
<channel>  
= (4 .. 20)  
<limit_num> = 1 or 2  
This command returns an integer that represents the DIGITAL I/O line  
active at the rear panel DIGITAL I/O connector for the specified channel  
and alarm limit. If default settings are in effect, returns follow the table  
below.  
I/O 4  
Chan  
4
I/O 5  
Chan  
5
I/O 6  
Chan  
6
I/O 7  
Chan  
7
8
9
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
If there is no association between an alarm and DIGITAL I/O line, there is  
no return and an Execution Error is generated.  
Example: ALARM_ASSOC? 10,1 returns 2 [For channel 10, alarm Limit 1,  
will assert DIGITAL I/O line 2].  
ALARM_ASSOC_CLR  
Clear Alarm Association  
Clears an alarm output association at the rear panel DIGITAL I/O  
connector for channels 4 to 20.  
ALARM_ASSOC_CLR <channel>,<limit_num>  
<channel>  
= (4 .. 20)  
<limit_num> = 1 2  
This command removes all association between a DIGITAL I/O line at the  
rear panel DIGITAL I/O connector for the specified channels 4 to 20 and  
alarm limit. After application of this command, the previously associated  
DIGITAL I/O line is set high and new alarm conditions on this channel’s  
alarm limit will not assert the DIGITAL I/O line. If this command is entered  
during scanning while logging to the memory card, and Execution Error is  
generated.  
Example: ALARM_ASSOC>CLR 10,1 [Channel 10, alarm Limit 1, remove  
all association with a DIGITAL I/O line.]  
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4
Table 4-5. Command and Query Reference (cont)  
ALARM_DO_LEVEL  
Alarm Digital Output Level  
Configures rear panel ALARM OUTPUTS lines for I/O functions.  
ALARM_DO_LEVEL <DO_line>,<DO_state>  
<DO_line> = (0 .. 3)  
<DO_state> = 1 (high) 0 (low)  
The rear panel ALARM OUTPUTS lines 0 to 3 are hard-wired to output  
alarm conditions for channels 0 to 3, respectively. If all or some of  
channels 0 to 3 are not configured for alarm outputs, the associated  
ALARM OUTPUTS line can be assigned to go logic high or low with this  
command. The line may be set to a logical low. (nominal =0.7V DC), or set  
to a logical high (nominal =5.0V DC).  
Example: ALARM_DO_LEVEL 3,0 [Set ALARM OUTPUTS line 3 to a  
logical 0.]  
ALARM_DO_LEVELS?  
Alarm Output State Query  
Returns an integer between 0 and 15 that summarizes the logical state of  
the rear panel ALARM OUTPUTS lines 0 to 3. Since the lines can be used  
as alarm outputs or DIGITAL I/O functions, the query represents the actual  
conditions at time of query. There are 16 possibilities, as shown below (0 =  
logic low):  
Line Line Line Line Returned  
3
2
1
0
Integer  
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0 -(all 4 alarms active)  
1
2
3
4
5
6
7
8
9
10  
11  
12  
13  
14  
15 -(no alarms active)  
Example: ALARM_DO_LEVELS? returns 15 [All lines are logic high.]  
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Table 4-5. Command and Query Reference (cont)  
ALARM_LIMIT  
Alarm Limit  
Set alarm limit 1 or 2 for any channel 0 to 20.  
ALARM_LIMIT <channel>,<limit_num>,<sense>,<value>  
<channel>  
= (0 .. 20)  
<limit_num> = 1 2  
<sense>  
<value>  
= HI LO OFF  
= Signed numeric quantity  
Two alarm limits, Limit 1 and Limit 2, can be assigned to any channel 0 to  
20 that is not in the OFF mode. An alarm limit can be used for high alarms,  
meaning a HI alarm is set if a measurement exceeds the high alarm level,  
or low alarms, meaning a LO alarm is set if a measurement falls below the  
low alarm level. If only one of the alarms is used, the other alarms is  
turned OFF. The alarm value can be any signed number between  
.00000001 and 9999999, however, the instrument rounds to five significant  
digits. The signed numeric entries can be entered in scientific notation or  
as real numbers. If no polarity sign is used, the value is assumed to be  
positive. Alarm limit settings automatically clear from a channel if the  
channel function is changed. If Mx+B scaling is applied, alarm settings are  
based on scaling, i.e., the actual instrument display, if this command is  
entered during scanning while logging to the memory card, an Execution  
Error is generated. Setting an alarm limit clears its alarm status and sets  
any associated ALARM or DIGITAL I/O line high.  
Example: ALARM_LIMIT 5, 1, LO, -65.872 [For channel 5, configure alarm  
Limit 1 as a low alarm with a value of -65.872.]  
ALARM_LIMIT?  
Alarm Limit Assignments Query  
Return alarm limit 1 or alarm limit 2 for any channel 0 to 20.  
ALARM_LIMIT? <channel>,<limit_num>  
<channel>  
= (0 .. 20)  
<limit_num> = 1 2  
For a selected channel and alarm limit, the returns include the sense of the  
alarm limit (HI, LO, OFF) plus the value of the alarm setting in scientific  
notation with five digits of resolution.  
Example: ALARM_LIMIT? 13, 1 returns LO, -4.5500E+0 [Channel 13,  
alarm Limit 1 is configured as a low alarm with a value of -4.55.]  
*CLS  
Clear Status  
(See front of table.)  
Set Date  
DATE  
Set instrument calendar values.  
DATE <month>,<date>,<year>  
<month> = (1 .. 12)  
<date> = (1 .. 31)  
<year> = (00 .. 99)  
Invalid values generate an Execution Error.  
Example: DATE 7,21,94 [Set date for July 21, 1994.]  
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4
Table 4-5. Command and Query Reference (cont)  
DIO_LEVELS? Digital I/O State Query  
Returns an integer between 0 and 255 that summarizes the logical state of the rear  
panel DIGITAL I/O lines 0 to 7. A logical 0 (low) means the line is asserted. Since the  
lines can be used as alarm outputs of digital inputs or outputs, the return represents the  
actual conditions at time of query. There are 256 possibilities, as shown in Appendix E.  
Example: DIO_LEVELS? returns 145 [DIGITAL I/O lines 1, 2, 3, 5 and 6 are asserted  
(logic low).]  
DIR  
Memory Card Files Directory  
Print a formatted listing of files on the memory card. This includes number of files, bytes  
used, and bytes free. While the directory is printing, all other operations in the  
instrument are suspended. If hardware or software flow control stall this output, the  
instrument waits for the output to be unstalled.  
Example; DIR returns:  
DAT00.HYD 826  
DAT01.HYD 1082  
SET00.HYD 730  
SET01 HYD 730  
07-21-1994  
07-21-1994  
07-21-1994  
07-21-1994  
16:20  
16:50  
17:10  
18:30  
4 FILE (S)  
3368 BYTES  
1030656 BYTES FREE  
DO_LEVEL  
Set Digital Output Level  
Configures the eight rear panel DIGITAL I/O connector lines, I/O connector lines, I/O 0  
to I/O 7.  
DO_LEVEL <DO_line>,<DO_state>  
<DO_line>  
<DO_state>  
=
=
(0 .. 7)  
1 0  
The rear panel DIGITAL I/O connector has eight lines, 0 to 7. Each line can be assigned  
to an I/O function. With this command, the line may be set to a logical low (nominal  
+0.7V DC), or set to a logical high (nominal +5.0V DC). DIGITAL I/O lines are asserted  
while scanning. When scanning stops, the I/O lines set logic low remain low unless  
values have been cleared by a new DO_LEVEL command, REVIEW_CLR, or by  
changing any parameter on any channel. Since I/O lines are shared with the alarm  
outputs of channels 4 to 20, verify DO_LEVEL commands will not cause ambiguities.  
(See the ALARM_ASSOC_CLR command to disassociate an alarm with an I/o line.) If  
this command is entered during scanning while logging to the memory card, an  
Execution Error is generated.  
Example: DO_LEVEL 4, 0 [Set I/o line 4 to a logical 0 (low).]  
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Table 4-5. Command and Query Reference (cont)  
Enable/Disable RS-232 Echo Mode  
ECHO <1 0>  
ECHO  
1 = Turn RS-232 echoing on.  
0 = Turn RS-232 echoing off.  
The echo on mode allows character strings sent from the host to the  
instrument, to return (echo) back to the host. When operating the  
instrument from a terminal (or computer in the terminal emulation mode),  
ECHO 1 is usually selected. If this command is entered during scanning  
while logging to the memory card, an Execution Error is generated.  
*ESE  
Event Status Enable  
(See front of table.)  
Event Status Enable Query  
(See front of table.)  
Event Status Enable Query  
(See front of table.)  
File Error Query  
*ESE?  
*ESR?  
FILE_ERROR?  
Returns an integer number representing the last memory card error that  
was encountered. Once set, this value is only cleared (set to zero) by  
performing this query.  
The possible card error codes are:  
0
No error since last queried or power up.  
Card error. No card, invalid file system on card, no file system on card,  
format operation failed, file could not be removed, and all other I/O  
errors.  
Bad file name, or out of file names (all 100 file names of the type being  
operated on are in used).  
Card error during scanning, but no data has been lost. Usually occurs  
when card fills during scanning.  
Card error during scanning, and data is being lost. The oldest scan data in  
queue is being lost as each new scan completes.  
Configuration File Load  
FILE_LOAD  
Loads the instrument configuration from a memory card configuration or  
data file.  
FILE_LOAD  
<file> = SET00.HYD, SET01.HYD, ... SET99.HYD  
-or-  
<file>  
<file> = DAT00.HYD, DAT01.HYD, ... DAT99.HYD  
Execution error if the file does not exist, if the file is not an instrument  
configuration or data file, if the file name is not valid, the card is not  
installed, or the card is not formatted. An execution error is also generated  
if either scanning or monitor is active. The file name convention is not  
checked (a data file may be loaded to recover a configuration).  
Example: FILE_LOAD SET68.HYD [Loads configuration file SET68.HYD  
as the new instrument configuration.]  
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4
Table 4-5. Command and Query Reference (cont)  
FILE_OPEN  
Data File Open  
Opens a data file for measurement logging.  
FILE_OPEN  
<file>  
<file> = DAT00.HYD, DAT01.HYD, DAT99.HYD  
All scans are appended to this file until a file close is performed. The  
special name ’*’ opens the next available file in sequence. If no higher  
numbered file can be found, the algorithm "wraps" to zero and keeps  
searching. If no more file names are available, an Execution Error is  
generated. If the given file already exists, the file name does not match the  
convention, or scanning is already active, an Execution Error is generated.  
Logging is turned on and the card destination activated if this command is  
successfully executed.  
Example: FILE_OPEN DAT31.HYD [Open data file DAT31.HYD for data  
logging.]  
FILE_OPEN?  
Data File Open Query.  
Returns the name of the data file to be used for logging, or an Execution  
Error if no file is open.  
Example: FILE_OPEN? returns DAT05.HYD [The file DAT05.HYD  
is open for data logging.]  
FILE_REMOVE  
File Remove  
Remove the given file from the memory card.  
FILE_REMOVE  
<file>  
<file> = DAT00.HYD, DAT01.HYD, ... DAT99.HYD  
or-  
<file> = SET00.HYD, SET01.HYD, ... SET99.HYD  
Removing the currently open data file will cause any scan data stored in  
internal memory waiting to be written to the file to be lost.  
An Execution Error is generated if the file does not exist, the card is write-  
protected, the file name is invalid, card is not installed or the card is not  
formatted. The file name convention is not checked.  
Example: FILE_REMOVE DAT00.HYD [Remove the DAT00.HYD file.]  
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Table 4-5. Command and Query Reference (cont)  
FILE_RX  
File Receive  
The normal serial protocol is suspended and a binary transfer (XMODEM)  
is started between the instrument memory card and the host computer.  
Received data is typically an instrument configuration file transmitted from  
the host computer and uses the naming convention, SETxx.HYD. If the file  
already exists it is overwritten.  
FILE_RX  
<file>  
<file> = SET00.HYD, SET01.HYD, ... SET99.HYD  
An Execution Error is generated under any of the following conditions: the  
card is not installed; the card is not formatted; the file cannot be created;  
scan or monitor is active; the instrument is configured for even or odd  
parity (parity must be "none"); or the instrument is configured for Echo On  
(Echo must be "Off"). See the FILE_TX command for transmitting data  
files. The file name convention is not checked, so any file may be  
transferred to the memory card.  
FILE_SPACE?  
FILE_STORE  
File Space  
Returns the number of kilobytes available for files on the memory card.  
Example: FILE_SPACE? returns 1003 [There are 1003 kilobytes free on  
the memory card.]  
Configuration File Store  
Saves present instrument configuration in the given file.  
FILE_STORE  
<file>  
<file> = SET00.HYD, SET01.HYD, ... SET99.HYD  
Configuration file names must match the naming convention ’SETxx.HYD’  
where xx is a two-digit integer number. If the given file already exists, it is  
overwritten. If there is not enough room to store a new configuration file, if  
the card is write-protected, card is not installed, or card is not formatted,  
an Execution Error is generated.  
Example: FILE_STORE SET21.HYD [Save the present instrument  
configuration in the file SET21.HYD.]  
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4
Table 4-5. Command and Query Reference (cont)  
FILE_TAG?  
Configuration File Tag  
Return the tag from the given configuration or data file (<file> specified), or  
the present configuration tag (no <file> specified).  
FILE_TAG?  
<file>  
<file>= DAT00.HYD, DAT01.HYD, ... DAT99.HYD  
-or-  
<file> = SET00.HYD, SET01.HYD, ... SET99.HYD  
-or- leave blank  
Instrument-created configurations use the configuration file name  
SETxx.HYD for this tag. If no tag has ever been used since the last full  
reset, or the specified file does not exist, an Execution Error is generated.  
Example: FILE_TAG? SET17.HYD returns TESTFILE [Present  
configuration tag in SET17.HYD is the string TESTFILE (set by the user).]  
FILE_TX  
File Transmit  
The normal serial protocol is suspended and a binary transfer (XMODEM)  
is started between the instrument memory card and the host computer.  
The instrument will transmit a DATxx.HYD file or SETxx.HYD file to the  
host computer.  
FILE_TX  
<file>  
<file> = DAT00.HYD, DAT01.HYD, ... DAT99.HYD  
-or-  
<file> = SET00.HYD, SET01.HYD, ... SET99.HYD  
An Execution Error is generated under any of the following conditions: the  
card is not installed; the card is not formatted; the file does not exist; scan  
or monitor is active; the instrument is configured for even or odd parity  
(parity must be "none"); or the instrument is configured for Echo On (Echo  
must be "Off"). See the FILE_RX command for receiving instrument  
configuration files. The file name convention is not checked, so any file  
may be transferred to the memory card.  
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Table 4-5. Command and Query Reference (cont)  
FORMAT  
Response Format  
Set the output format type to include or exclude measurement units.  
FORMAT 1  
FORMAT 2  
Measurements returned without units.  
Measurements returned with units.  
Commands that return measurement data (like LAST?, NEXT?, MIN?,  
MAX?) can be expressed as a number only (FORMAT 1) or as a number  
with a measurement unit (FORMAT 2). If this command is entered during  
scanning while logging to the memory card, an Execution Error is  
generated. The measurement units are:  
MEASUREMENT  
Scaled  
Volts DC  
Volts AC  
Resistance  
Frequency  
UNITS STRING  
MX+B”  
“VDC”  
“VAC”  
“OHMS”  
“Hz”  
Temperature °C  
Temperature °F  
“C”  
“F”  
With FORMAT 1 asserted, typical returns would be +890.22E+0,  
+230.96E-3, 072.4E+0, +003.2E; with FORMAT 2 asserted, the returns  
would be +890.22E+0 HZ,+230.96E-3 VAC, 072.4E+0 F, +003.2E+0  
Mx+B.  
FORMAT?  
Query Response Format  
Returns the output format type.  
1
2
Measurements returned without units.  
Measurements returned with units.  
Commands that return measurement data (like LAST?, NEXT?, MIN?,  
MAX?) can be expressed as a number only (FORMAT 1) or as a number  
with a measurement unit (FORMAT 2). The measurement units are:  
MEASUREMENT  
Scaled  
Volts DC  
Volts AC  
Resistance  
Frequency  
UNITS STRING  
MX+B”  
“VDC”  
“VAC”  
“OHMS”  
“Hz”  
Temperature °C  
Temperature °F  
“C”  
“F”  
Example: FORMAT? returns 2 [Measurement data will be returned with a  
units indicator, e.g., +230.96E-3 VAC.]  
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Table 4-5. Command and Query Reference (cont)  
FUNC  
Channel Function Definition  
Define the Changing a channel configuration automatically erases values held in  
review, and resets all ALARM OUTPUTS and DIGITAL I/O lines to logical high. The  
FUNC command clears any alarm limits and scaling values for this channel;  
therefore, define a channel function before setting alarm limits and/or scaling values  
for that channel. measurement function and range for the indicated channel.  
FUNC <channel>, <function>, <range>, <terminals>  
<channel> = 0, 1,2, ...20  
<function> = OFF, VDC, VAC, OHMS, FREQ, TEMP  
<range> = 1,2,3,...6, AUTO [VDC, VAC,OHMS, FREQ]  
<range> = J, K, E, T, N, R, S, B, C [TEMP with thermocouples]  
<range> = PT [TEMP with RTDs]  
<terminals> = 2 or 4  
Ohms and temperature measurements that use a 4-terminal configuration are limited  
to channels 1 to 10. Select a channel function, OFF, VDC, VAC, OHMS, FREQ, or  
TEMP. For voltage, ohms or frequency, select a range 1 to 6, as specified in the  
table below (or AUTO for autoranging) For temperature, select a thermocouple type,  
or PT for RTDs.  
RANGE  
VOLTAGE  
300 mV  
3 V  
OHMS  
300 e  
3 ke  
FREQUENCY  
900 HZ  
9 kHz  
1
2
3
4
5
6
30 V  
30 ke  
300 ke  
3 Me  
90 kHz  
150/300 V*  
90 mV**  
900 mV**  
900 kHz  
1 Mhz  
10 Me  
*300V only on channels 0, 1, and 11  
** Volts DC only  
The <terminals> selection is specified only when the function type is OHMS, or  
TEMP using an RTD. The 2-terminal selection is valid on any channel. The 4-  
terminal selection is valid only for channels 1 to 10 (n), which automatically clears a  
channel a decade higher (n+10).  
Example: FUNC 9,TEMP, PT,2 [Set the function of channel 9 to temperature  
measurements using a Platinum RTD, and the 2-terminal connection.] Example:  
FUNC 5,VDC,4 [Set the function of channel 5 to volts DC, and use the 150V scale.]  
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Table 4-5. Command and Query Reference (cont)  
FUNC?  
Channel Function Query  
Return the complete function for the indicated channel.  
FUNC?  
<channel>  
<channel> = (0 .. 20)  
The returns are in comma-separated data fields using the following format:  
<function>,<range>,<terminals>  
The <function> return is OFF, VDC, VAC, OHMS, FREQ, or TEMP. For voltage,  
ohms, or frequency the <range> return is a number 1 through 6 (see below) or  
AUTO for autoranging. The <range> return for temperature is a thermocouple type  
[J, K, E, T, N, R, S, B, C] or PT for RTD measurements. The <terminals> return is for  
OHMS and TEMP functions only and is either 2 for 2-terminal measurements or 4 for  
4-terminal measurements.  
Example: FUNC? 8 returns TEMP, PT,4 [The function of channel 8 is temperature,  
using a Platinum resistance-temperature-detector (RTD), and a 4-terminal  
measurement configuration  
*IDN?  
IEE  
Identification Query  
(See front of table.)  
Instrument Event Enable  
Sets the Instrument Event Enable Register to the given value.  
IEE  
<value>  
<value> = (0 .. 255)  
The IEE register is used to enable or disable (mask) the output bits of the Instrument  
Event Register (IER). The combined output of the IEE and IER is the Instrument  
Event Bit (IEB), which is used as an input for the Status Byte Register. See the  
discussion on status registers for more  
information.  
Example: IEE 5 [Enables the IER output byte 00000101 (decimal 5), which means  
an Open Thermocouple -or- Alarm Limit Transition will set IEB logic high.]  
IEE?  
IEE?  
Instrument Event Enable Query  
Returns the present value of the Instrument Event Enable Register as an integer.  
Instrument Event Register Query  
Returns the present value of the Instrument Event Enable Register (IEE) as an  
integer, as selected with the IEE command. See the discussion on status registers  
for more information.  
Example: IEE? returns 128 [The IEE register is set for 10000000 (decimal 128),  
which means a Scan Complete will set IEB logic high.]  
Instrument Event Register Query  
IER?  
Returns the value of the Instrument Event Register (IER) as an integer, then clears  
the register to 0. See the discussion on status registers for more information.  
Example: IER? returns 133 [The IER register is set for 10000101 (decimal 133),  
which means a Scan Complete, Open Thermocouple, and Alarm Limit Transition  
were detected.]  
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Table 4-5. Command and Query Reference (cont)  
INTVL  
Set Scan Interval  
Set scan interval time.  
INTVL <hours>,<minutes>,<seconds>  
<hours> = (0 .. 9)  
<minutes> = (0 .. 99)  
<seconds> = (0 .. 99)  
An Execution Error is generated if values outside the specified ranges are used or if  
the instrument is scanning.  
Example: INTVL 1,30,0 [Set the interval time to 1 hour, 30 minutes and 0 seconds.]  
Scan Interval Query  
INTVL?  
LAST?  
Return scan interval time. Returns the scan interval time in the format  
<hours>,<minutes>,<seconds>.  
Example INTVL? returns 0,0,0 [The interval time is 0 hours, 0 minutes, and 0  
seconds (continuous scanning).]  
Channel’s Last Scan Value  
Returns the last measured value(s) for the scan in progress or the last completed  
scan.  
LAST?  
<channel>  
<channel> = 0, 1, 2, ... 20  
Returns last measurement values for either the indicated channel, or for all defined  
channels if the <channel> field is left blank. An Execution Error results if a request is  
made for a channel defined as OFF, the channel specified is invalid, the channel  
specified has been set up but not yet measured, or Review array values have been  
cleared by REVIEW_CLR, or by changing any parameter on any channel. The  
returned value is a signed number with decimal point and exponent. For slow  
scanning rate, 5 digits are returned (+/-XX.XXXE+/-N); for fast scanning rate, 4 digits  
are returned (+/-XX.XXE+/-N). The channel range setting determines placement of  
the decimal point. A return of +001.00E+9 indicates an overload (OL) condition; a  
return of +009.00E+9 indicates an open thermocouple (otc) condition. If no channel  
specification is made, all the last values of the scanned channels are returned, each  
separated by a comma.  
Example: LAST? 1 returns +0074.4E+0 [The last scanned value of channel 1 is  
74.4.]  
Example: LAST? returns +060.14E+0,+013.84E+0,+009.00E+9 [Three channels  
were scanned. The first channel had a last reading of 60.14; the second channel had  
a last reading of 13.84; the third channel reading indicates an open thermocouple  
(RATE 0 and FORMAT 1 are asserted).]  
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Table 4-5. Command and Query Reference (cont)  
LOCK  
Lock and unlock the instrument front panel control keys. The LOCK modes disable  
the front panel keys, while placing the instrument in either REVIEW (LOCK 1),  
MONITOR (LOCK 2) or Configuration Lock (LOCK 3). This limits instrument  
operation to a specific mode and prevents unauthorized configuration changes. Only  
supervisory personnel should be aware that the F and B keys can be used to  
toggle the LOCK modes on and off, except for LOCK 3, which is reset from the  
computer interface only or by loading a non-LOCK 3 setup file.  
LOCK modes 1 and 2 are not saved/restored in configuration files. If one of these  
modes is active when FILE_STORE is performed, mode 0 (unlocked) is stored in the  
file.  
LOCK  
<mode>  
<mode> = 0,1,2,3  
LOCK 0  
Unlock the front panel and turn off the REM (remote) annunciator.  
All key functions are  
enabled. This command is used to clear  
a LOCK 1, LOCK 2, or LOCK 3 condition.  
LOCK 1  
LOCK 2  
LOCK 3  
Lock the front panel in the REVIEW mode and turn on the REM  
(remote) annunciator.  
keys are unlocked to allow the review of the  
Only the up/down and left/right arrow  
minimum,  
maximum, and last values of any channel. The front panel can be  
unlocked by using the LOCK 0 command, or by simultaneously  
pressing the front panel F and B keys. The F and B  
keys can be used toggle between the locked and  
modes, while in REVIEW.  
unlocked  
Lock the front panel in the MONITOR mode (which must be active  
or the command will generate an execution error) and turn on the  
REM (remote) annunciator. Only the up/down arrow keys are  
unlocked to allow the monitoring of any channel. The front panel  
can be unlocked by using the LOCK 0 command, or by  
simultaneously pressing the front panel F and B keys. The  
F and b keys can be used to toggle between  
the locked  
and unlocked modes, while in MON.  
Lock the channel configuration. The instrument operates normally  
except keys used to configure a channel are disabled, that is , the  
configuration is locked. A configuration file can be loaded; scan  
can be turned on/off, monitor on/off, and review on/off. Exit this  
mode using the power-up configuration-reset sequenced from the  
instrument front panel  
out disabled.  
or load a configuration file that has lock-  
The four LOCK states are nonvolatile. If power is interrupted, the instrument retains  
the last LOCK setting.  
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4
Table 4-5. Command and Query Reference (cont)  
Returns the instrument front panel lock status, as selected with the LOCK command.  
LOCK?  
0
1
Front panel keys are unlocked. All key functions are enabled.  
Front panel keys are locked, except for up/down and left/right arrow  
keys, which are used to review the minimum, maximum and last  
values of any channel  
2
3
Front panel keys are unlocked, except for the up/down arrow keys,  
which are used to monitor any channel.  
Front panel keys can be used, except those used to configure a  
channel.  
LOCS  
LOG?  
Local without Lockout  
All front panel keys are enabled, and the REM annunciator is not lit. This is the state  
assumed by the instrument at power-up reset. To disable all the front panel keys,  
use the LWLS command.  
Retrieve Logged Data Query  
Return the oldest logged scan values for all configured channels and remove them  
from internal memory (maximum 100 scans). This query is valid during scanning.  
The remaining count of stored scans (LOG_COUNT? command) is decremented by  
1. Channels defined as OFF are not included. If there are no logged scans to  
remove, an  
Execution Error is generated.  
The returns includes the following information:  
Date and time at the start of the logged scan.  
Values for the channels measured.  
Status of ALARM OUTPUTS, DIGITAL I/O, and totalize count.  
Logging scans in internal memory is enabled by the PRINT and PRINT_TYPE  
commands.  
Example: LOG? returns 16,15,30,7,21,94,+034.53E-3 VAC,+09.433E+0  
VDC,+1.2043E+6 OHMS,15,255,+00.000E+3 [The oldest recorded scan, that  
started at 1600 hours, 15 minutes, 30 seconds, on July 21, 1994, measured three  
channels with readings 34.53mVAC, 9.433 VDC, 1.2043 M OHMS, with ALARM  
OUTPUTS status 15, DIGITAL I/O status 255, and totalize count of 0 (RATE 0 and  
FORMAT 2 are asserted).]  
Retrieve specified scan data from internal memory.  
LOGGED? <index>  
LOGGED?  
<index>  
=
(1,2, 3, .. , 100)  
A maximum of 100 scans can be recorded in the internal memory. This command is  
used to retrieve a particular scan. If the <<index>> number has no associated scan,  
an Execution Error is returned. Logging scans in internal memory is enabled by the  
PRINT and PRINT_TYPE commands.  
Scan data is returned in the same format as for the LOG? query.  
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Table 4-5. Command and Query Reference (cont)  
LOG_BIN?  
Binary Upload of Logged Data  
Returns a single ASCII string, which encodes the raw binary data stored at the  
specified <index> position.  
LOG_BIN?  
<index>  
<index> = 1, 2, 3, ... 100  
See Appendix C for a discussion of the LOG_BIN? command.  
LOG_CLR  
Clear Logged Scans  
Clear all stored scan data from internal memory (maximum 100 scans).  
Clear Oldest Logged Scan  
LOG_CLR_1  
Clears the oldest (first) scan in the internal memory. If there are no scans in internal  
memory, an Execution Error is generated. A total of 100 scans can be saved in the  
log queue.  
LOG_COUNT?  
Logged Scan Count Query  
Return the number of stored scans. Returns an integer value representing the  
number of scans presently stored in memory. (maximum 100) 0 indicates that there  
are no stored scans.  
Logging scans in internal memory is enabled by the PRINT and PRINT_TYPE  
commands.  
Example: LOG_COUNT? returns 33 [The internal memory holds data from the last  
33 scans.]  
LOG_MODE  
Action when Internal Memory is Full.  
Determines what action is taken when 100 scans have been recorded  
LOG_MODE 0  
LOG_MODE 1  
the oldest scans and record new scans.  
Maintain the oldest scans and discard new  
The LOG_MODE setting is nonvolatile and cannot be changed from the instrument  
front panel. The default is LOG_MODE 0.  
LOG_MODE?  
Action when Internal Memory is Full Query  
Returns 0 or 1 to indicate what action will be taken when 100 scans have been  
recorded  
0
1
Discarding the oldest scans to record new scans.  
Maintaining the oldest scans and discarding new scans  
LWLS  
Local with Lockout  
All front panel keys are disabled. The REM annunciator is not lit. This command can  
be used when the instrument is scanning or monitoring. To clear, use the LOCS  
command.  
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4
Table 4-5. Command and Query Reference (cont)  
MAX?  
Channel’s Maximum Value  
Returns the maximum value(s) measured since the review array was last cleared.  
Channel’s Maximum Value  
MAX?  
<channel>  
<channel> = 0, 1, 2, ...20, or leave blank  
Returns maximum measurement values for either the indicated channel, or for all  
defined channels if the <channel> field is left blank. An Execution Error results if a  
request is made for a channel defined as OFF, the channel specified is invalid, the  
channel specified has been set up but not yet measured, or Review array values  
have been cleared by REVIEW_CLR, or by changing any parameter on any channel.  
The return is a signed number with decimal point and exponent. For slow scanning  
rate, 5 digits are returned (+/-XX.XXXE+/-N); for fast scanning rate, 4 digits are  
returned (+/-XX.XXE+/-N). The channel range setting determines placement of the  
decimal point. A return of +001.00E+9 indicates an overload (OL) condition; a return  
of +009.00E+9 indicates an open thermocouple (otc) condition. If no channel  
specification is made, all the maximum values of the scanned channels are returned,  
each separated by a comma.  
Example: MAX? 1 returns +022.34E+0 [The maximum scanned value of channel 1 is  
22.34.]  
Example: MAX? returns +009.00E+9,+890.22E+0,+230.96E-3 [Three channels were  
scanned. The first channel shows an open thermocouple; the second channel had a  
maximum reading of 890.22; the third channel had a maximum reading of 0.230  
(RATE 0 and FORMAT 1 are asserted).]  
Memory Card Status  
MCARD?  
Returns the memory card status as an encoded integer number from a binary  
number using bits 0 to 4.  
Bit 0 - Card changed; remaining bits differ from the last query  
Bit 1 - A card is present in the unit  
Bit 2 - Card is write protected  
Bit 3, 4 - Battery status of last inserted card, as below:  
BIT 4  
BIT 3  
MEMORY CARD BATTERY STATUS  
Battery operational  
Battery should be replaced; data is OK  
Battery and data integrity not guaranteed  
Battery and data integrity not guaranteed  
0
0
1
1
0
1
0
1
Example: MCARD? returns 7 [The memory card status is 00111 (decimal 7),  
meaning the card changed since the last query, a card is in the unit, the card is write  
protected, and battery is operational.]  
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Table 4-5. Command and Query Reference (cont)  
MCARD_DIR?  
Memory Card Directory  
Returns a terminated string for each file in the root directory of the memory card. The  
string is a comma-separated list of the file’s name, size, modification date (day,  
month, year) and time (hours, minutes, seconds).  
Example: MCARD_DIR? returns:  
DAT00.HYD,826,7,21,1994,16,20,44  
DAT01.HYD,810,7,21,1994,16,50,10  
SET00.HYD,730,7,21,1994,17,10,32  
SET01.HYD,730,7,21,1994,18,30,03  
MCARD_FORMAT Format Memory Card  
Memory card inserted in the Data Bucket will be formatted. The card must be the  
static RAM (SRAM) type, meeting PCMCIA standards. An Execution Error is  
generated and the card not formatted if scanning is in progress, the card is of  
unknown size, or card is write-protected. If the memory card contains a PCMCIA  
card information structure (CIS), the card size is determined from the CIS.  
Otherwise, the size is algorithmically determined by writing to the memory card. A  
CIS is never written to the card.  
When formatting a memory card, any scan data that has been stored in internal  
memory waiting to be written to a valid memory card will be lost.  
MCARD_SIZE?  
Memory Card Size  
Returns the memory card size as an integer number of kilobytes.  
Example: MCARD_SIZE? returns 1024 [Memory card size is 1024 kilobytes (1  
megabyte).]  
MIN?  
Channel’s Minimum Value  
Returns the minimum value(s) measured since the review array was last cleared.  
MIN?  
<channel>>  
<channel> = 0, 1, 2, ... 20, or leave blank  
Returns minimum measurement values for either the indicated channel, or for all  
defined channels if the <channel>field is left blank. An Execution Error results if a  
request is made for a channel defined as OFF, the channel specified is invalid, the  
channel specified has been set up but not yet measured, or Review array values  
have been cleared by REVIEW_CLR, or by changing any parameter on any channel.  
The return is a signed number with decimal point and exponent. For slow scanning  
rate, 5 digits are returned (+/-XX.XXXE+/-N); for fast scanning rate, 4 digits are  
returned (+/-XX.XXE+/-N). The channel range setting determines placement of the  
decimal point. A return of +001.00E+9 indicates an overload (OL) condition; a return  
of +009.00E+9 indicates an open thermocouple (otc) condition. If no channel  
specification is made, all the minimum values of the scanned channels are returned,  
each separated by a comma.  
Example: MIN? 16 returns +167.85E+3 [The minimum scanned value of channel 16  
is 167,850 (RATE 0 and FORMAT 1 are asserted).]  
Example: MIN? returns +091.67E+0,+001.00E+9,+115.21E-3 [Three channels were  
scanned. The first channel had a minimum reading of 91.67; the second channel is  
in overload (OL); the third channel had a minimum reading of 0.11521 (RATE 0 and  
FORMAT 1 are asserted).]  
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4
Table 4-5. Command and Query Reference (cont)  
MON  
Enable/Disable Monitoring  
This command performs the same function as on the front panel.  
MON  
1
<channel>  
<channel> = 0, 1, 2 ... 20  
Disables monitoring  
MON  
0
The <channel> parameter can be 0 through 20. A command error is generated if no  
<channel> parameter is given when enabling monitoring. If the channel to be  
monitored is invalid or defined as OFF, or if values other than 0 or 1 are given, an  
Execution Error is generated.  
The MON and SCAN commands work in conjunction with the front panel controls.  
The Monitor and Scan functions can be enabled or disabled from either the front  
panel or the computer interface. The most recently specified monitor channel (from  
front panel or computer interface) becomes the one channel monitored.  
Example: MON 1,6 [Turn on monitor and monitor channel 6.]  
Example: MON 0 [Turn monitor off.  
MON_CHAN?  
Monitor Channel Number  
This query asks for the number of the presently defined monitor channel. If  
monitoring is not active, an Execution Error is generated.  
Example: MON_CHAN? returns 9 [Channel 9 is being monitored.]  
Example: MON_CHAN? returns nothing and generates an  
Execution Error [No channel is being monitored.]  
Monitor Channel Value  
MON_VAL?  
This query asks for a measurement on the monitor channel. If monitoring is not  
active, an Execution Error results. A return of +001.00E+9 indicates an overload  
(OL) condition; a return of +009.00E+9 indicates an open thermocouple (otc)  
condition.  
Example: MON_VAL? returns +115.67E+0 VAC [The channel being monitored was  
measured to have a value of 115.67 VAC (RATE 0 and FORMAT 2 are asserted).]  
Example: MON_VAL? returns nothing and generates an Execution Error [No  
channel is being monitored.]  
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Table 4-5. Command and Query Reference (cont)  
NEXT?  
Next Scan’s Values  
The NEXT? query returns data values for the next scan to complete. If a scan is in  
progress when the NEXT? query is processed, the data values returned are from the  
scan in progress. If a scan is not presently in progress, the NEXT? query waits for  
data to become available. While waiting, no other commands can be issued. To exit  
NEXT? while waiting, use <CNTL><C>.  
NEXT? returns comma-separated information for the date and time at the start of the  
next measurement scan, the values for channels measured, the state of the Digital  
I/O lines, and the totalizer count.  
The time and date are returned in the following order: Hours (0-23), Minutes (0-59),  
Seconds (0-59), Month (1-12), Date (1-31), Year (0-99). Measurement data is  
returned as a list of scientific notation values. For an overload (OL), "+001.00E+9" is  
returned. If an open thermocouple is detected, "009.00E+9" is returned.  
ALARM OUTPUTS and DIGITAL I/O values are returned as integer values. (To  
decode the ALARM OUTPUTS integer, see the ALARM_DO_LEVELS? command;  
to decode the DIGITAL I/O integer, see the DIO_LEVELS? command. ) The  
Totalizer value is returned as a scientific notation value.  
Example: NEXT? returns 16,11,47,7,21,94,+1.0099E+3, +04.556E+0,-  
13.665E+0,+1.2664E+6,+009.00E+9,15,255, +00.455E+3 [At 1600 hours, 11  
minutes, 47 seconds, on July 21, 1994, five channels were scanned with the  
measurements 1009.9, 4.556, -13.665, 1,266,400, open thermocouple,  
Alarms I/O status was 15, DIGITAL I/O status was 255, and totalizer count was 455  
(RATE 0 and FORMAT 1 are asserted).]  
Example: NEXT? returns nothing and the computer interface does not accept  
commands [The NEXT? command was entered when the instrument was not  
scanning. Press the front panel Q key, or enter <CNTL><C> to clear the NEXT?  
command.]  
*OPC  
Operation Complete  
(See front of table.)  
*OPC?  
PRINT  
Operation Complete Query  
(See front of table.)  
Data Logging Enable/Disable  
The destination and conditions for data logging are determined by the PRINT_TYPE  
command, while this command enables or disables the logging of the measurement  
data.  
PRINT 0 Disable data logging to memory card and printer  
PRINT 1 Enable data logging to memory card and printer  
The PRINT command does not affect the logging of data (100 scans maximum) to  
the internal memory (log queue), which is always active when selected as a  
destination (PRINT_TYPE 1,2,5, or 6). If scanning is already active, an Execution  
Error is generated.  
When PRINT 1 is asserted, the instrument front panel PRN (Logging) annunciator is  
on. When PRINT 0 is asserted, the instrument front panel PRN annunciator is off.  
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Table 4-5. Command and Query Reference (cont)  
PRINT?  
Data Logging Query  
Returns the status of data logging, as selected with the PRINT command.  
0
1
PRINT 0 is selected (data logging disabled)  
PRINT 1 is selected (data logging enabled  
PRINT_TYPE  
Set Data Logging Type  
Set the destination and condition for data logging. When data logging is enabled  
with the PRINT command, the destination and conditions are set with the  
PRINT_TYPE command. The <destination< is selected with an integer (0 to 6), and  
the <type< is selected with an integer (0 to 2). Internal memory is limited to 100  
scans. To extract the data from the internal memory, see the LOG? and LOGGED?  
commands. Attempting to use this command to select a memory card as the logging  
destination while scanning will cause an Execution Error.  
PRINT_TYPE  
<destination>, <type>  
<destination> = 0, 1, 2, ... 6  
0 = Log data to printer  
1 = Log data to log queue  
2 = Log data to log queue and printer  
3 = Log data to memory card  
4 = Log data to memory card and printer  
5 = Log data to memory card and log queue  
6 = Log data to memory card, log queue, and printer  
<type< = 0, 1 or 2  
0 = Record all scans  
1 = Record scans if any scanned channel is in alarm  
2 = Record scans when any alarm transitions  
When the log queue is selected as the destination, all scans area automatically  
recorded in the log queue as if type 0 was selected. types 1 and 2 are ignored for  
the log queue, but are still executed for other destinations selected (i.e., the printer  
and memory card.  
The PRINT command does not affect the logging of data (100 scans maximum) to  
the internal memory (log queue), which is always active when selected as a  
destination (PRINT_TYPE 1,2,5 or 6).  
Example: PRINT_TYPE 3,1 [When data logging is enabled (see PRINT command),  
send data to the memory card but only if one of the scanned channels is in alarm.]  
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Table 4-5. Command and Query Reference (cont)  
PRINT_TYPE?  
Data Logging Type Query  
Returns the status of data logging destination and condition, as selected with the  
PRINT_TYPE command. Returns two integers in the form <destination<,<type> as  
follows:  
<destination> = 0, 1, 2, ... 6  
0 = Log data to printer  
1 = Log data to internal memory  
2 = Log data to internal memory and printer  
3 = Log data to memory card  
4 = Log data to memory card and printer  
5 = Log data to memory card and internal memory  
6 = Log data to memory card, internal memory, and printer  
<type< = 0, 1 or 2  
0 = Record all scans  
1 = Record scans if any scanned channel is in alarm  
2 = Record scans when any alarm transitions  
Example: PRINT_TYPE? returns 5,0 [Destination for logged data is to the memory  
card and internal memory, and all scans are recorded.]  
RANGE?  
Channel Range Query  
Returns the range(s) used for the scan in progress or the last completed scan. If a  
channel is configured for autoranging, the actual range used for the measurement is  
returned.  
RANGE?  
<channel>  
<channel> = 0, 1, 2, ... 20, or leave blank  
If the <channel> specification field is left blank, values for all defined channels are  
returned. An Execution Error results if a request is made for a channel defined as  
OFF, the channel specified is invalid, or if the channel has been set up but not  
measured with at least one scan. The range value returned is not affected by Mx+B  
scaling.  
An integer value (1-6) is returned, based on the table below. Temperature functions  
(thermocouple and RTD) always return a 1. Commas separate the integers if the  
return is for all scanned channels.  
RANGE  
VOLTAGE  
OHMS  
FREQUENCY  
1
2
3
4
5
6
300 mV  
3 V  
30 V  
150/300 V*  
90 mV**  
900 mV**  
300e  
3 ke  
30 ke  
300 ke  
3 Me  
10 Me  
900 Hz  
9 kHz  
90 kHz  
900 kHz  
1 Mhz  
*300 V only on channels 0 and 11.  
**Volts DC only.  
Example: RANGE? 12 returns 3 [Channel 12 has a range of 3. If measuring voltage,  
it would indicate the 30V scale.].  
Example: RANGE? returns 2,2,1,6 [Four channels were scanned. The first and  
second have a range of 2, the third a range of 1, and the fourth a range of 6.]  
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Table 4-5. Command and Query Reference (cont)  
RATE  
Select Measurement Rate  
Specifies the measurement rate. Changing the measurement rate also clears the  
Review array, and ALARM OUTPUTS and DIGITAL I/O lines.  
RATE 0  
RATE 1  
Selects the slow measurement rate.  
Selects the fast measurement rate.  
Selection of the fast measurement rate using the RATE 1 command will speed up  
the measurement portion of the scan interval; however, the measurement resolution  
is four digits instead of five digits. For example, a reading of +115.32 with a slow  
measurement rate would be +115.3 with the fast measurement rate. An Execution  
Error is generated if the argument is not 0 or 1 or if the instrument is scanning.  
RATE?  
REMS  
Measurement Rate Query  
Return measurement rate for the instrument.  
0 Measurement rate is slow  
1
Measurement rate is fast  
Remote without Lockout  
Places the instrument in the remote mode, lights the front panel REM annunciator,  
and only two front panel keys are active (with special REMS functionality):  
The Q key triggers a single scan.  
The K key returns the instrument to normal front panel control.  
To return the instrument to normal front panel control with a command, use the  
LOCS command.  
REVIEW_CLR  
Clear Review Values  
Clear all minimum, maximum, and last values (all channels) in the Review array. (It  
is not possible to selectively clear individual entries in the Review array.) The Review  
clearing operation is carried out at any time, except during the measurement portion  
of the scan internal. only at the completion of any scan in progress. Clearing the  
Review array also clears ALARM OUTPUTS and DIGITAL I/O lines to a logic high..  
Reset  
*RST  
(See front of table.)  
RTD Ice Point (R0)  
RTD_R0  
For the indicated channel, store the numeric data as the RTD R0 ice point  
resistance, i.e., the resistance of the RTD at 32°F (0°C). Changing the ice point also  
clears the Review array and ALARM OUTPUTS and DIGITAL I/O lines. (The 0  
portion of R0 in the RTD_R0 command is the number zero.) The default value is  
100.00.  
RTD_R0  
<channel<, <R0>  
<channel> = 0,1,2 ... 20  
<R0> = 000.00 to 999.99  
An Execution Error is generated if the R0 value supplied is not within the indicated  
range, the channel specified is invalid, the channel is defined as OFF, or  
measurements are active.  
Example: RTD_R0 6, 124.85 [For channel 6, set the R0 ice point resistance to a  
value of 124.85.]  
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Table 4-5. Command and Query Reference (cont)  
RTD_R0?  
RTD Ice-Point (R0) Query  
Returns the RTD R0 (ice-point resistance) value for the indicated channel. (The 0  
portion of R0 in the RTD_R0 command is the number zero.)  
RTD_R0?  
<channel>  
<channel< = 0,1,2, ... 20  
If the channel number is invalid, an Execution Error is generated. If a channel is  
defined OFF, or if no change has been made to R0 for a channel, the value  
"+100.00E+0" (default) is returned.  
RWLS  
Remote with Lockout (RS-232 only)  
Enter the IEEE-488.1 remote with front panel lockout (RWLS) state. All front panel  
buttons are disabled, and the REM annunciator is lit.  
If this command is used with the IEEE-488 interface, an Execution Error is  
generated.  
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Table 4-5. Command and Query Reference (cont)  
SCALE_MB  
Set Mx+B Scaling Values  
Set the M and B scaling values for the indicated channel, and display the results of  
the Mx+B calculation in the indicated display range. Changing the Mx+B of any  
channel also clears the Review array, and resets ALARM OUTPUTS and DIGITAL  
I/O lines.  
SCALE_MB  
<channel>,<M_value>,<B_value>,<range>  
<channel> = (0 .. 20)  
<M_value> = signed numeric quantity  
<B_value> = signed numeric quantity  
<range> = (1 .. 16)  
The range code for the display <range> is shown below  
Range  
Code  
Display  
Offset  
Value  
Max B  
1
2
3
4
5
6
7
8
0.0000 m  
00.000 m  
000.00 m  
0000.0 m  
0.0000 x1  
00.000 x1  
000.00 x1  
0000.0 x1  
0.0000k  
9.9999E-3  
99.999E-3  
999.99E-3  
9999.9E-3  
9.9999  
99.99  
999.99  
9999.9  
9.9999E3  
99.999E3  
999.99E3  
9999.9E3  
9.9999E6  
99.999E6  
999.99E6  
9999.9E6  
9
10  
11  
12  
13  
14  
15  
16  
00.000k  
000.00 k  
0000.0 k  
0.0000 M  
00.000 M  
000.00 M  
0000.0 M  
When M=1 and B=0, there is no Mx+B scaling. The entries for M and B must be  
between +/-0.0001E-3 and +/-9999.9E+6. An Execution Error is generated by invalid  
entries, a channel set to OFF, if the instrument is  
scanning, or if the range code is too low for the selected B value. For example, the  
minimum display range for B=1000 is code 8. Mx+B scaling values for a channel are  
automatically reset to 1 (M) and 0 (B) when the function for that channel is changed.  
Returned measurements for a channel with Mx+B scaling has a function identifier of  
MX+B (when FORMAT 2 has been asserted).  
Example: SCALE_MB 18,+.55555,-17.777,6 [For channel 18, M=+.55555, B=-  
17.777, and the display range is 00.000 x1.]  
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Users Manual  
Table 4-5. Command and Query Reference (cont)  
SCALE_MB?  
Mx+B Scaling Values Query  
Return the M and B scaling values for the indicated channel.  
SCALE_MB?  
<channel>  
<channel> = 0, ... 20  
This command returns three values. The first two are the M and B values for the  
channel indicated, even when M=1 and B=0 or the channel function is defined as  
OFF. These first two values are returned in M and B order and in scientific notation  
format with five digits of resolution. The third value returned indicates the Mx+B  
display range. The Mx+B scaling values are automatically reset to 1 (M) and 0 (B)  
when the function for that channel is changed.  
The range code for the display <range> is shown below:  
Range  
Code  
Display  
Offset  
Value  
Max B  
1
2
3
4
5
6
7
8
0.0000 m  
00.000 m  
000.00 m  
0000.0 m  
0.0000 x1  
00.000 x1  
000.00 x1  
0000.0 x1  
0.0000k  
9.9999E-3  
99.999E-3  
999.99E-3  
9999.9E-3  
9.9999  
99.99  
999.99  
9999.9  
9.9999E3  
99.999E3  
999.99E3  
9999.9E3  
9.9999E6  
99.999E6  
999.99E6  
9999.9E6  
9
10  
11  
12  
13  
14  
15  
16  
00.000k  
000.00 k  
0000.0 k  
0.0000 M  
00.000 M  
000.00 M  
0000.0 M  
Example: SCALE_MB? 0 returns +1.0000E+0,-1.0000E+3,9 [For channel 0, M=1,  
B=-1000, and the display range is 0.0000 k.]  
Enable/Disable Scanning  
SCAN  
This command performs the same function as Q on the front panel.  
SCAN 1  
SCAN 0  
Enable scanning.  
Disable scanning  
If SCAN 0 is set during the measurement interval of the scan, the measurement  
portion is completed. If SCAN 0 is set during the countdown interval of the scan, the  
scan is immediately terminated.  
If there are no configured channels (all are defined as OFF) or values other than 0 or  
1 are given, an Execution Error is generated.  
The MON and SCAN commands work in conjunction with the front panel controls.  
The Monitor and Scan functions can be enabled or disabled from either the front  
panel or the computer interface. The most recently specified monitor channel (from  
front panel or computer interface) becomes the one channel monitored.  
Front panel Q and M buttons work only when the lockout state is “local without  
lockout” (see the LOCS command)..  
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4
Table 4-5. Command and Query Reference (cont)  
SCAN?  
Scan Query  
Returns the scanning status, as selected with the SCAN command.  
0
1
Scanning is disabled  
Scanning is enabled  
If a scan is in progress, a "1" is returned at the end of the scan. (A response delay  
may occur if SCAN? is sent early in a scan.) This feature allows synchronization for  
other commands that would not be recognized if received during a scan. For  
example, SCAN?;*TRG could be used to trigger a new scan after completion of the  
current scan, where just a *TRG command sent while a scan is in progress would be  
discarded. If a scan is not in progress, a "0" is returned immediately.  
SCAN_TIME?  
Time of Scan  
Returns values indicating the time and date at start of last scan.  
Uses the same format and order as the TIME_DATE? query. The data is returned in  
the following order: Hours (0-23), Minutes (0-59), Seconds (0-59), Month (1-12),  
Date (1-31), Year (0-99).  
Example: SCAN_TIME? returns 7,56,50,7,21,94 [The start of the last scan was at  
0700 hours, 56 minutes, 50 seconds, on July 21, 1994.]  
*SRE  
Service Request Enable  
(See front of table.)  
*SRE?  
Service Request Enable Query  
(See front of table.)  
*STB?  
Read Status Byte Query  
(See front of table.)  
Temperature Configuration  
TEMP_CONFIG  
Set temperature configuration using the given value. Changing the temperature  
configuration also clears the Review array, and ALARM OUTPUTS and DITGITAL  
I/O lines.  
TEMP_CONFIG  
<value>  
<value> = 0. 1, 2 , 3  
Selects the temperature scale (°C or °F) and enables or disables thermocouple  
detection. When thermocouple detection is enabled and an open thermocouple is  
detected, the monitor display will show "otc" and the measurement return is  
+009.00E+9. When thermocouple detection is disabled and an open thermocouple is  
detected, the monitor display will show "OL" and the measurement return is -  
001.00E+9. These settings affect every channel; they cannot be set for each  
channel individually. The command is entered when the instrument is not scanning.  
Select the desired <value> from the table below.  
Value  
Meaning  
0
1
2
3
OTC Disable and °C  
OTC Disable and °F  
OTC Enable and °C  
OTC Enable and °F  
Example: TEMP_CONFIG 3 [Measure temperature in °F and enable "otc" detection.]  
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Users Manual  
Table 4-5. Command and Query Reference (cont)  
TEMP_CONFIG?  
Temperature Configuration Query  
Returns the status of the temperature configuration, as selected with the  
TEMP_CONFIG command. Returns an integer 0, 1, 2, or 3, which corresponds to  
the temperature configuration, as shown in the table below.  
Value  
Meaning  
0
1
2
3
OTC Disable and °C  
OTC Disable and °F  
OTC Enable and °C  
OTC Enable and °F  
Example: TEMP_CONFIG? returns 2 [“otc” detection is enabled and the temperature  
scale is °C.]  
TIME  
Set the instrument time.  
TIME  
<hours>,<minutes>  
<hours> = (0 .. 23) (24-hour scale, 18:00 = 6:00 pm).  
<minutes> = (0 .. 59)  
[seconds] = (0, ... 59)  
Invalid values generate an Execution Error. The [seconds] field can be left blank,  
automatically entering 00.  
Example: TIME 16,30,15 [Set the clock for 1600 hours (4 pm), 30 minutes, and 15  
seconds.]  
TIME_DATE?  
Retrieve Time and Date  
Returns comma-separated integer values for time, date, and year using the following  
format:  
hours  
minutes  
seconds  
month  
day  
0-23  
0-59  
0-59  
1-12  
1-31  
00-99  
year  
The TIME command is used to set hours, minutes, and seconds.  
Example: TIME_DATE? returns 2, 43, 12, 7, 21, 94 [The time is 0200 hours, 43  
minutes, 12 seconds, on July 21, 1994  
TOTAL  
Set Totalizer Count  
Give the Totalizer count a new initial value.  
TOTAL  
<t_value>  
<t_value> = (0 .. 65535)  
If the value is not in the range 0 through 65,535, an Execution Error is generated.  
Setting the totalizer count also clears the Totalize Overflow bit in the Instrument  
Event Register (see Figure 4-3). Clear the Totalizer count by setting the Totalizer to  
zero (0).  
Example: TOTAL 12000 [Set the totalizer count to 12000 Clear the Totalizer count  
by setting the Totalizer to zero (0).  
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4
Table 4-5. Command and Query Reference (cont)  
TOTAL?  
Totalizer Value Query  
Returns the value of the present Totalizer count. Format of the value is +00.000E+3.  
When the Totalizer has overflowed, the value returned is +001.00E+9.  
Example: TOTAL? returns 13.465E+3 [The present value of the totalizer count is  
13,465.]  
TOTAL_DBNC  
Set Totalizing Debounce  
Set totalizing input debounce state, which adds a delay of 1.75 ms to each transition,  
allowing increased accuracy from totalizer inputs from contact closures.  
TOTAL_DBNC  
<dbnc_state>  
<dbnc_state> = 1 (on)  
0
(off)  
Use of any other value causes an Execution Error to be generated. At initial power  
up, totalize debounce is disabled (0). An Execution Error is generated if the totalizer  
debouhce setting is changed when scanning while logging to the memory card is  
enabled.  
TOTAL_DBNC?  
Totalizer Debounce Query  
Returns the totalizing input’s debounce state, as selected with the TOTAL_DBNC  
command.  
0 Debounce is off  
1 Debounce is on  
SIngle-Scan Trigger  
*TRG  
(See front of table.)  
Select Trigger Type  
TRIGGER  
Select the type of scan triggering option. The use of a trigger option has the same  
effect as pressing the front panel Q key. An input for an external trigger is  
available at the ALARM OUTPUTS connector on the rear panel of the instrument,  
pins TR and GROUND (TRIGGER 1). Scanning can also be enabled when a  
monitored channel goes into alarm (TRIGGER 2).  
TRIGGER 0  
TRIGGER 1  
TRIGGER 2  
External trigger and Alarm trigger disabled  
External trigger enabled  
Alarm trigger enabled  
TRIGGER 0 means external triggering is disabled and only normal scan interval  
triggering can be used. If this command is entered during scanning while logging to  
the memory card, an Execution Error is generated.  
TRIGGER 1 means that external triggering is enabled. An acceptable low input (-0.6  
to +0.8V dc) between the pins TR and GROUND on the ALARM OUTPUTS  
connector on the rear panel will cause the instrument to start scanning. When the  
TR input returns to logic high, scanning is disabled. External trigger inputs during a  
scan are ignored.  
TRIGGER 2 means the alarm trigger is enabled. When a channel being monitored  
goes into alarm, the instrument starts scanning. When the channel being monitored  
goes out of alarm, the instrument stops scanning. The *TRG and GET commands  
can be used with a trigger option selection.  
If the trigger type given is not one of the listed values, an Execution Error is  
generated.  
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Users Manual  
Table 4-5. Command and Query Reference (cont)  
TRIGGER?  
Trigger Type Query  
Returns an integer representing the present trigger type:  
0
1
2
External trigger and Alarm trigger disabled  
External trigger enabled  
Alarm trigger enabled  
*TST?  
*WAI  
Self Test Query  
(See front of table.)  
Wait-to-continue  
(see front of table)  
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4
10 ' HYDRALOG.BAS Hydra Program to scan VDC, VAC, OHMS, FREQ or TEMP  
20 '  
30 '  
40 '  
50 '  
60 '  
70 '  
- initializes RS-232 Communications between PC and Hydra  
- configures a number of Hydra channels for one type  
of measurement (e.g., VDC, VAC, temperature, etc.)  
- scan channels 3 times, and display and record measurement  
data in file "TESTDATA.PRN"  
80 ' NOTE: Hydra must be set up for RS-232 communications, 9600 baud,  
90 '  
no parity, 8 bit data  
100 '  
110 KEY OFF  
120 '  
' Switch keyboard event trapping off  
130 ' NOTE: Error message checking is not done here -- QBasic will notify the  
140 ' user and exit if there is a problem  
150 '  
160 ' Open Communications port with 9600 baud, no parity, 8 it data,  
170 '  
180 '  
ignore Clear to Send, Data Set Ready, and Carrier Detect.  
190 OPEN "COM2:9600,N,8,,cs0,ds0,cd0" FOR RANDOM AS #1  
200 '  
210 '  
220 OPEN "testdata.PRN" FOR OUTPUT AS #2  
230 '  
240 PRINT #1, "ECHO 0"  
250 '  
' Open data file  
' Turn off command echo on Hydra  
260 '-----  
270 ' Find out the number of channels the user wants to configure  
280 ' NOTE: Channel 0 will not be used  
290 '  
300 NUMCHANNELS = 0  
310 WHILE (NUMCHANNELS < 1) OR (NUMCHANNELS > 20)  
320  
INPUT "Enter the number of channels to be scanned (1-20): ", NUMCHANNELS  
330 WEND  
340 '  
350 'Turn unused channels off  
360 PRINT "(Wait...)"  
370 '  
380 FOR INDEX = (NUMCHANNELS + 1) TO 20  
390  
400  
PRINT #1, "FUNC " + STR$(INDEX) + ",OFF"  
GOSUB 1120  
410 NEXT INDEX  
420 '  
430 '  
440 'Configure Hydra Channels  
450 ' First, initialize screen and display Hydra identification info  
460 CLS  
470 LOCATE 1, 25: PRINT "Sample Program for Hydra"  
480 PRINT #1, "*IDN?": GOSUB 1120: LINE INPUT #1, RESULT$  
490 LOCATE 2, 20: PRINT RESULT$  
500 '  
510 WHILE (1)  
520  
530  
540  
550  
560  
570  
580  
590  
600  
610  
'Print banner line at bottom of screen  
LOCATE 25, 1  
PRINT "1 = VDC  
2 = VAC  
3 = OHMS  
4 = FREQ  
5 = TEMP  
6 = Quit";  
' Get channel configurations  
FUNC$ = "0"  
WHILE (FUNC$ < "1") OR (FUNC$ > "6")  
LOCATE 23, 1: INPUT "  
WEND  
Selection: ", FUNC$  
' Exit and clean up if choice is "Quit"  
IF FUNC$ = "6" THEN CLOSE 1, 2: CLS : KEY ON: END  
op51f.eps  
Figure 4-4. Sample Program (GWBASIC) (1 of 2)  
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Users Manual  
620 '  
630  
640  
' Set up the common channel configuration string (function and range)  
IF (FUNC$ = "1") THEN CONFIG$ = "VDC, 1"  
650  
IF (FUNC$ = "2") THEN CONFIG$ = "VAC, 1"  
660  
670  
IF (FUNC$ = "3") THEN CONFIG$ = "OHMS, 1, 2" ' Assuming 2-terminal channel  
IF (FUNC$ = "4") THEN CONFIG$ = "FREQ, 1"  
680  
IF (FUNC$ = "1") THEN CONFIG$ = "TEMP, K"  
' Assuming K thermocouple  
690 '  
700  
710  
'Set up Hydra / Configure channels  
LOCATE 23, 1: PRINT "Programming Hydra...";  
FOR INDEX = 1 TO NUMCHANNELS  
720  
730  
740  
PRINT #1, "FUNC " + STR$(INDEX) + "," + CONFIG$  
GOSUB 1120  
750  
NEXT INDEX  
760 '  
770  
LOCATE 23, 1: PRINT "Measuring " + CONFIG$ + "  
"
780 '  
790  
800  
' Scan three times  
FOR INDEX = 1 TO 3  
810  
820  
PRINT #1, "*TRG"  
GOSUB 1120  
' Start a single scan  
' Get prompt back from Hydra  
830  
PRINT #1, "SCAN_TIME?": GOSUB 1120  
840  
850  
LINE INPUT #1, RESULT$  
PRINT #2, RESULT$  
' Get scan time stamp  
' Save time stamp to data file  
860  
FOR CHANNELINDEX = 1 TO NUMCHANNELS  
' Get scan data  
870  
880  
PRINT #1, "LAST? " + STR$(CHANNELINDEX) ' Request channel data  
GOSUB 1120  
890  
INPUT #1, RESULT$  
' Get channel result  
900  
LOCATE CHANNELINDEX + 2, 25  
910  
PRINT "Chan " + STR$(CHANNELINDEX) + ": ";  
920  
930  
940  
950  
PRINT RESULT$  
PRINT #2, RESULT$ + ",";  
NEXT CHANNELINDEX  
PRINT #2, ""  
' Print results to screen  
' Print results to data file  
' End of line to data file  
960  
NEXT INDEX  
970 WEND  
980 END  
990 '  
1000  
1010  
1020  
1030  
1040  
1050  
1060  
1070  
1080  
1090  
1100  
1110  
1120  
1130  
1140  
1150  
1160  
1170  
1180  
1190  
1200  
1210  
'
'
'
' CHECKRESPONSE Subroutine  
' This subroutine checks the Hydra prompt after sending a command to  
' Hydra, to see if an error occurred  
'
' The possible responses are:  
'
'
'
'
"=>(CR)(LF)"  
"?>(CR)(LF)"  
"!>(CR)(LF)"  
(command successful)  
(command syntax error)  
(command execution error)  
PROMPT$ = INPUT$(4, #1)  
' Get prompt  
'Command successful  
IF INSTR(1, PROMPT$, "=>") <> 0 THEN RETURN  
IF INSTR(1, PROMPT$, "?>") <> 0 THEN  
PRINT "Command Syntax Error!"  
ELSEIF INSTR(1, PROMPT$, "!>") <> 0 THEN  
PRINT "Command Execution Error!"  
END IF  
'
PRINT "Program execution halted due to communications errors"  
END  
op51_1f.eps  
Figure 4-5. Sample Program (GWBASIC) (2 of 2)  
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4
' HYDRALOG.BAS Hydra Program to scan VDC, VAC, OHMS, FREQ or TEMP  
'
'
'
'
'
- initializes RS-232 Communications between PC and Hydra  
- configures a number of Hydra channels for one type  
of measurement (e.g., VDC, VAC, temperature, etc.)  
- scan channels 3 times, and display and record measurement  
data in file "TESTDATA.PRN"  
' NOTE: Hydra must be set up for RS-232 communications, 9600 baud,  
'
no parity, 8 bit data  
KEY OFF  
' Switch keyboard event trapping off  
' NOTE: Error message checking is not done here -- QBasic will notify the  
' user and exit if there is a problem  
' Open Communications port with 9600 baud, no parity, 8 it data,  
'
ignore Clear to Send, Data Set Ready, and Carrier Detect.  
OPEN "COM2:9600,N,8,,cs0,ds0,cd0" FOR RANDOM AS #1  
OPEN "testdata.PRN" FOR OUTPUT AS #2  
PRINT #1, "ECHO 0"  
' Open data file  
' Turn off command echo on Hydra  
'-----  
' Find out the number of channels the user wants to configure  
' NOTE: Channel 0 will not be used  
NumChannels = 0  
WHILE (NumChannels < 1) OR (NumChannels > 20)  
INPUT "Enter the number of channels to be scanned (1-20): ", NumChannels  
WEND  
'Turn unused channels off  
PRINT "(Wait...)"  
FOR Index = (NumChannels + 1) TO 20  
PRINT #1, "FUNC " + STR$(Index) + ",OFF"  
GOSUB CheckResponse  
NEXT Index  
op52_1f.eps  
Figure 4-5. Sample Program (QBASIC) (1 of 3)  
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'Configure Hydra Channels  
' First, initialize screen and display Hydra identification info  
CLS  
LOCATE 1, 25: PRINT "Sample Program for Hydra"  
PRINT #1, "*IDN?": GOSUB CheckResponse: LINE INPUT #1, Result$  
LOCATE 2, 20: PRINT Result$  
WHILE (1)  
'Print banner line at bottom of screen  
LOCATE 25, 1  
PRINT "1 = VDC 2 = VAC 3 = OHMS 4 = FREQ 5 = TEMP 6 = Quit";  
' Get channel configurations  
Func$ = "0"  
WHILE (Func$ < "1") OR (Func$ > "6")  
LOCATE 23, 1: INPUT "  
WEND  
' Exit and clean up if choice is "Quit"  
Selection: ", Func$  
IF Func$ = "6" THEN CLOSE 1, 2: CLS : KEY ON: END  
' Set up the common channel configuration string (function and range)  
SELECT CASE Func$  
CASE "1"  
Config$ = "VDC, 1"  
CASE "2"  
Config$ = "VAC, 1"  
CASE "3"  
Config$ = "OHMS, 1, 2" ' Assuming 2-terminal channel  
CASE "4"  
Config$ = "FREQ, 1"  
CASE "5"  
Config$ = "TEMP, K"  
END SELECT  
' Assuming K thermocouple  
'Set up Hydra / Configure channels  
LOCATE 23, 1: PRINT "Programming Hydra...";  
FOR Index = 1 TO NumChannels  
PRINT #1, "FUNC " + STR$(Index) + "," + Config$  
GOSUB CheckResponse  
NEXT Index  
LOCATE 23, 1: PRINT "Measuring " + Config$ + "  
"
' Scan three times  
FOR Index = 1 TO 3  
PRINT #1, "*TRG"  
GOSUB CheckResponse  
' Start a single scan  
' Get prompt back from Hydra  
PRINT #1, "SCAN_TIME?": GOSUB CheckResponse  
LINE INPUT #1, Result$  
PRINT #2, Result$  
FOR ChannelIndex = 1 TO NumChannels  
' Get scan time stamp  
' Save time stamp to data file  
' Get scan data  
PRINT #1, "LAST? " + STR$(ChannelIndex) ' Request channel data  
GOSUB CheckResponse  
INPUT #1, Result$  
' Get channel result  
LOCATE ChannelIndex + 2, 25  
PRINT "Chan " + STR$(ChannelIndex) + ": ";  
PRINT Result$  
PRINT #2, Result$ + ",";  
' Print results to screen  
' Print results to data  
file  
NEXT ChannelIndex  
PRINT #2, ""  
' End of line to data file  
NEXT Index  
WEND  
END  
op52_2f.eps  
Figure 4-6. Sample Program (QBASIC)(2 of 3)  
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4
CheckResponse:  
' CHECKRESPONSE Subroutine  
' This subroutine checks the Hydra prompt after sending a command to  
' Hydra, to see if an error occurred  
' The possible responses are:  
'
'
'
"=>(CR)(LF)"  
"?>(CR)(LF)"  
"!>(CR)(LF)"  
(command successful)  
(command syntax error)  
(command execution error)  
PROMPT$ = INPUT$(4, #1)  
' Get prompt  
'Command successful  
IF INSTR(1, PROMPT$, "=>") <> 0 THEN RETURN  
IF INSTR(1, PROMPT$, "?>") <> 0 THEN  
PRINT "Command Syntax Error!"  
ELSEIF INSTR(1, PROMPT$, "!>") <> 0 THEN  
PRINT "Command Execution Error!"  
END IF  
PRINT "Program execution halted due to communications errors"  
END  
op52_3f.eps  
Figure 4-6. Sample Program (QBASIC) (3 of 3)  
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2635A  
Users Manual  
/*  
* HYDRALOG.C Hydra Program to scan VDC, VAC, OHMS, FREQ or TEMP  
*
*
*
*
*
*
- initializes RS-232 Communications between PC and Hydra  
- configures a number of Hydra channels for one type  
of measurement (e.g., VDC, VAC, temperature, etc.)  
- scan channels 3 times, and display and record measurement  
data on the screen and in file "testdata.prn"  
* This program uses routines from the GreenLeaf Communications Library  
* (asiopen(), asiputs(), and asigets_timed()) for sending and receiving  
* information from the serial port connected to the Hydra. We recommend  
* the use of a third-party serial communications library when developing  
* C programs to communicate with Hydra instruments over PC serial ports.  
*/  
/*  
* NOTE: Hydra must be set up for RS-232 communications, 1200 baud,  
*
no parity, 8 bit data  
*/  
#include <stdio.h>  
#include <string.h>  
#include <errno.h>  
#include "asiports.h"  
static FILE *testdata;  
/* Greenleaf CommLib include file */  
/* File handle for output data file */  
main(argc,argv)  
int argc;  
char *argv[];  
{
int ret_code;  
/* code returned by various GreenLeaf  
communications functions */  
unsigned numChannels;  
unsigned index;  
/* Number of channels to be scanned */  
/* counter */  
char response[30];  
char sendbuff[129];  
char recvbuff[129];  
/* Buffer for user response */  
/* local buffer for transmitting to Hydra */  
/* local buffer for receiving from Hydra */  
/* Open and initialize COM2, the serial port the Hydra unit is attached  
to, for 1200 baud, no parity, 8 it data, and ignore DTR and CTS */  
ret_code = asiopen( COM2, (ASINOUT | BINARY | NORMALRX), 1000, 1000,  
1200L, P_NONE, 1,8,FALSE,FALSE );  
if ( ret_code < ASSUCCESS ) {  
fprintf(stderr,"Failed to open the port, Greenleaf error: %d.\n",  
ret_code );  
exit(1);  
}
/*send reset and uninstall */  
asiputc (com2, '\x11');  
asiputc (com2, '\x03');  
checkResponse ();  
/* Get prompt */  
op53_1f.eps  
Figure 4-6. Sample Program (QuickC) (1of 5)  
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4
asiputs( COM2, "ECHO 0", -2); /* Turn off command echo on Hydra */  
checkResponse(); /* Get prompt */  
/* Open data file TESTDATA.PRN */  
if((testdata = fopen("testdata.prn","w")) == NULL)  
{
perror("Cannot open testdata.prn");  
exit(1);  
}
/* Find out the number of channels the user wants to configure  
NOTE: Channel 0 will not be used */  
numChannels = 0;  
while((numChannels < 1) || (numChannels > 20))  
{
fprintf(stdout,"Enter the number of channels to be scanned (1-20):");  
gets(response);  
numChannels = atoi(response); /* convert ascii response to numeric */  
}
/* Turn off unused channels */  
fprintf(stdout,"\nWait....\n");  
for(index = numChannels + 1; index < 21; ++index)  
{
sprintf(sendbuff,"FUNC %d, OFF",index);  
asiputs(COM2,sendbuff,-2);  
checkResponse();  
/* get prompt */  
}
/* Print Header and Hydra identification header */  
fprintf(stdout,"\n\nSample Program for Hydra\n");  
asiputs(COM2,"*IDN?",-2); /* Ask for Hydra identification info */  
checkResponse();  
/* Get prompt */  
asigets_timed(COM2,recvbuff,256,-2,TICKS_PER_SECOND*2); /* Receive Hydra  
identification  
header */  
fprintf(stdout,"%s\n\n",recvbuff);  
/*  
* Configure channels and scan until user chooses to Quit  
*/  
while(1)  
{
int func;  
char configStr[14];  
/* Configuration setting */  
/* channel function string */  
/*  
* Configure Hydra Channels  
*/  
op53_2f.eps  
Figure 4-7. Sample Program (QuickC) (2 of 5)  
4-63  
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2635A  
Users Manual  
/* Request channel configuration from user */  
fprintf(stdout,"1 = VDC\t\t2 = FAC\t\t3 = OHMS\t4 = FREQ\t5 =  
TEMP\t\t6 = Quit\n");  
func = 0;  
do  
{
fprintf(stdout," Selection (1-6): ");  
gets(response);  
func = atoi(response);  
} while((func < 1) || (func > 6));  
if(func == 6)  
break;  
/* If Quit, exit program */  
switch(func)  
{
/* set configuration string */  
case 1:  
strcpy(configStr,"VDC,1");  
break;  
case 2:  
strcpy(configStr,"VAC,1");  
break;  
case 3:  
strcpy(configStr,"OHMS,1,2"); /* Assuming 2-terminal channel */  
break;  
case 4:  
strcpy(configStr,"FREQ,1, 1");  
break;  
case 5:  
strcpy(configStr,"TEMP, K"); /* Assuming K thermocouple */  
break;  
}
/* Send configuration to Hydra */  
fprintf(stdout,"Programming Hydra...\n");  
for(index = 1;index <= numChannels;++index)  
{
sprintf(sendbuff,"FUNC %d,%s",index,configStr);  
asiputs(COM2,sendbuff,-2);  
checkResponse();  
/* get prompt */  
}
op53_3f.eps  
Figure 4-7. Sample Program (QuickC) (3 of 5)  
4-64  
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Computer Operations  
Computer Interface Commands and Operation  
4
/*  
* Scan and receive data  
*/  
fprintf(stdout,"\nMeasuring %s...\n",configStr);  
for(index=0;index < 3;++index)  
{
/* scan three times */  
unsigned chanIndex; /* Channel counter */  
asiputs(COM2,"*TRG",-2); /* trigger scan */  
checkResponse();  
/* get prompt */  
asiputs(COM2,"SCAN_TIME?",-2); /* request time stamp for scan */  
checkResponse();  
/* get prompt */  
/* receive time stamp for scan, and write to  
data file */  
asigets_timed(COM2,recvbuff,256,-2,TICKS_PER_SECOND*2);  
fprintf(testdata,"%s\n",recvbuff);  
for(chanIndex = 1; chanIndex <= numChannels; ++chanIndex)  
{
/* get value scanned for each channel */  
sprintf(sendbuff,"LAST? %d",chanIndex);  
asiputs(COM2,sendbuff,-2); /* request value for channel */  
checkResponse(); /* get prompt */  
/* receive value for channel and write to  
screen and data file */  
asigets_timed(COM2,recvbuff,256,-2,TICKS_PER_SECOND*2);  
fprintf(stdout,"Chan %d: %s, ",chanIndex,recvbuff);  
fprintf(testdata,"%s,",recvbuff);  
}
fprintf(stdout,"\n");  
fprintf(testdata,"\n");  
}
fprintf(stdout,"\n");  
fprintf(testdata,"\n");  
}
fclose(testdata);  
exit(0);  
}
op53_4f.eps  
Figure 4-7. Sample Program (QuickC)(4 of 5)  
4-65  
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2635A  
Users Manual  
/*  
* This function checks the Hydra prompt after sending a command to Hydra,  
* to see if an error occurred.  
*
* Possible responses are:  
*
*
*
"=>(CR)(LF)"  
"?>(CR)(LF)"  
"!>(CR)(LF)"  
(Command successful)  
(Command syntax error)  
(Command execution error)  
*/  
static int checkResponse()  
{
char response[129];  
/* Gets string from Hydra -- asigets_timed  
gets characters from the receive buffer,  
and strips the (CR)(LF) characters from  
the end before placing them in the  
"response" buffer */  
asigets_timed(COM2,response,128,-2,TICKS_PER_SECOND*2);  
/* check to see if the command worked correctly */  
if(strcmp(response,"=>") == 0)  
return 0;  
/* command executed without error */  
if(strcmp(response,"?>") == 0)  
fprintf(stderr,"Command Syntax Error!\n");  
else  
{
if(strcmp(response,"!>") == 0)  
fprintf(stderr,"Command Execution Error!\n");  
}
fprintf(stderr,"\nProgram execution halted due to communications errors\n");  
fclose(testdata);  
exit(1);  
}
op53_5f.eps  
Figure 4-7. Sample Program (QuickC)(5 of 5)  
4-66  
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Chapter 5  
Printer Operations  
Title  
Page  
Summary of Printer Operations......................................................................... 5-3  
Connecting the Instrument to a Printer.............................................................. 5-3  
Configuring for Printer Operations ................................................................... 5-5  
Printing Measurement Data and Memory Card Directory ................................ 5-6  
Problems?...................................................................................................... 5-6  
Printing Measurement Results During Scanning.......................................... 5-6  
Printing the Review Array ............................................................................ 5-8  
Printing the Directory of the Memory Card.................................................. 5-9  
5-1  
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2635A  
Users Manual  
DATA BUCKET  
REVIEW  
LAST  
HYDRA  
CH  
mA  
mVDCAC  
Hz  
M
k
V
COM  
REVIEW  
CLEAR  
FILES  
MODE  
INTVL  
SCAN  
CLOCK  
ALRM  
FUNC  
Mx+B  
SINGLE  
300V  
MAX  
RATE  
MON  
TOTAL  
ZERO  
ENTER  
LIST  
SHIFT  
CANCEL  
TRIGS  
COMM  
LOCAL  
BATT  
BUSY  
op83f.eps  
5-2  
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Printer Operations  
Summary of Printer Operations  
5
Summary of Printer Operations  
Printer operations allow an RS-232 connection between the instrument and a printer to  
print out measurement results during scanning, the Review array, and a directory of the  
memory card files. The printer must accept a serial data input, either directly or via a  
serial-to-parallel converter. Measurement data recorded onto the memory card cannot be  
printed out from the instrument (see Memory Card Operations, Chapter 3). The  
information in this chapter is provided in three parts:  
Connecting the Instrument to a Printer  
Configuring for Printer Operations  
Printing Measurement Data and Memory Card Directory  
Connecting the Instrument to a Printer  
The two most common configurations for connecting the instrument to a printer are  
shown in Figure 5-1. Printers with an RS-232 serial data interface may be used directly,  
while printers with a parallel input require a serial-to-parallel converter. For other  
configurations, refer to your printer manual. A complete discussion of RS-232  
connections and cables, including cable fabrication information, is provided in Appendix  
D.  
Note  
Several printers use cables that have a DB-25 connector at one end. This  
does not necessarily indicate connectivity with the instrument RS-232 port.  
Examples include parallel interface printer cables, and 8-pin mini-circular  
cables. Check your printer manual before making any connections if there  
is doubt about the interface.  
5-3  
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2635A  
Users Manual  
SERIAL-INPUT  
PRINTER  
HYDRA  
PRINTER  
RS-232  
DB-25  
CONNECTOR  
RS-232  
(DB-9)  
FLUKE RS40 OR RS42 CABLE  
RS-232  
(DB-25)  
(OR EQUAL)  
(MALE)  
(RS40 MALE  
OR RS42 FEMALE)  
PRINTER  
PARALLEL-INPUT  
PRINTER  
HYDRA  
CENTRONICS-  
TYPE  
36-PIN  
CONNECTOR  
SERIAL-TO-PARALLEL  
CONVERTER  
RS-232  
(DB-9)  
FLUKE RS40 OR RS42 CABLE  
(OR EQUAL)  
COM PORT  
(DB-25)  
(MALE)  
(RS40 MALE  
OR RS42 FEMALE)  
op54f.eps  
Figure 5-1. Connecting the Instrument to a Printer  
5-4  
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Printer Operations  
Configuring for Printer Operations  
5
Configuring for Printer Operations  
Correct operation of the instrument RS-232 link with a printer depends on the link  
parameters baud rate, parity, and CTS (Clear To Send). Perform the procedure in Figure  
5-3 to establish communication link parameters. Refer to your printer manual for  
information on selecting identical parameters for the printer, usually through the setting  
of DIP (dual in-line package) switches (with the printer unpowered). The instrument uses  
a fixed one start bit and one stop bit.  
SHIFT  
Selecting the bAUd (Baud) Rate. Press the  
SHIFT key, release, and then press the LIST key  
bAUd  
LIST  
to open the communications parameters menu.  
The baud rate sets the rate of data transfer  
between the instrument and the printer.  
Normally, the highest compatible rate is selected.  
Select the rate using the up/down arrow keys  
then press ENTER.  
38400  
19200  
9600  
4800  
2400  
1200  
600  
300  
ENTER  
ENTER  
ENTER  
ENTER  
Selecting PAR (Parity).  
The 8th bit of a  
PAR  
character can be set to make all characters odd  
(Odd) or even (E), or no parity at all (no). The  
printer checks parity (if selected) and indicates  
when an error is detected. Select the parity then  
press ENTER.  
no  
E
Odd  
Selecting CtS (Clear To Send). The RS-232  
CTS line (pin 8) is an input control line from the  
printer Request to Send (RTS) line (pin 4). When  
CTS is a Logic high, the instrument is allowed to  
transmit data. If the printer RS-232 interface  
does not have or use an RTS line, select OFF  
then press ENTER.  
CtS  
On  
OFF  
Selecting Echo.  
When echo is On, each  
Echo  
character sent to the instrument is "echoed" back  
to the host. For this RS-232 application, Echo  
has no meaning because the printer does not  
send characters to the Hydra.  
selection then press ENTER.  
On  
OFF  
Make the  
Typical  
Required  
op55f.eps  
Figure 5-2. Configuring the RS-232 Ports for Print Operations  
5-5  
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2635A  
Users Manual  
Printing Measurement Data and Memory Card Directory  
An RS-232 link between the instrument and a printer allows printing of the following  
data:  
Printing Measurement Results During Scanning (Figure 5-3)  
Printing the Review Array (Figure 5-4)  
Printing the Memory Card Directory(Figure 5-5)  
The following procedures describe the operation of this link. Before continuing, verify  
the instrument and the printer have been properly connected (Figure 5-1), and configured  
for operation (Figure 5-2).  
Problems?  
If the printer does not operate after the RS-232 connection has been made and the  
instrument and printer RS-232 parameters have been set, check the following:  
1. No characters. No operation of any kind usually indicates a cabling problem,  
hardware incompatibility (e.g., connecting to a printer with a parallel input), or the  
printer is not on-line and ready for operation (ribbon, paper, power, interlocks, etc.).  
2. Incorrect characters. Incorrect printer function (rapid paper feeds, wrong characters)  
usually indicates a configuration incompatibility, i.e., the instrument and printer  
baud rate and parity dont match.  
3. Missed characters. The Data Bucket Hydra Series II RS-232 port is different from  
the RS-232 port on the Data Acquisition Hydra Series II (Model 2620A) and Data  
Logger Hydra Series II (Model 2625A), because of the addition of three modem  
control lines, CTS, RTS, and DSR (see Appendix D). If the printer occasionally  
loses characters, the printer may need to control the data flow from the instrument.  
Try enabling CTS "on" to see if this solves the problem.  
Printing Measurement Results During Scanning  
Perform the procedure in Figure 5-3 to print measurement results during scanning. The  
destination for the scanned data can be the printer, memory card, both the printer and the  
memory card, or no destination, where the data is saved only in the Review array. The  
mode for the printing to the printer or memory card can be all scanned data, scanned data  
only when any scanned channel is in alarm, or scanned data only when an alarm  
transitions from one alrm stat to another.  
5-6  
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Printer Operations  
Printing Measurement Data and Memory Card Directory  
5
SHIFT  
FILES  
Setting the DESTINATION Parameter. Press  
the SHIFT key, release, then press the FILES  
key to open the destination menu. Select both  
(Both) to route measurement data to both the  
memory card and printer; select Print (Printer) to  
route measurement data just to the printer. After  
selection, press ENTER.  
dESt  
both  
Print  
CArd  
nonE  
ENTER  
Selecting the Destination Mode.  
destination mode determines when the printer  
should print. Select trAns (Transition) to print  
The  
MOdE  
ALL  
ALAr  
trAnS  
one complete scan when  
a
channel has  
transitioned into or out of an alarm limit. Select  
ALAr (Alarm) to print all channel scans while any  
channel is in an alarm condition (stopping when  
all channels are out of alarm). Select ALL (All) to  
print all scans. (See example printout below.)  
Typical  
Required  
ENTER  
Channel 3  
Scanned Channels  
Time  
(In High/High Alarm)  
(0, 1, 3, 9, 12, 18)  
(Hours/Minutes/Seconds)  
Date  
(Month/Day/Year)  
18:29:57 07/21/94  
0: 980.19 kOHMS  
9: 113.45 mVAC  
1: -023.85 VDC  
12: 084.32 F  
3: 115.23 VAC H/H  
L/ 18: 004.19 MX+B /H  
ALM:7 DIO:175 TOTAL:0  
Digital I/0 Status  
(See Table 2-5)  
Channel 12  
(In Low Alarm)  
Channel 18  
(In High Alarm)  
(Mx+B Scaled)  
Alarm Status  
(See Table 2-4)  
Totalizer Count  
(See Figure 2-20)  
op56f.eps  
Figure 5-3. Printing Measurement Results During Scanning  
5-7  
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2635A  
Users Manual  
Printing the Review Array  
Perform the procedure in Figure 5-4 to print the Review array, which consists of the last,  
maximum, and minimum measurement values during the last scan, and previous scans if  
the instrument configuration has not changed or the review array cleared. If the Review  
array is blank (cleared), an error message is displayed with an audible "beep." If this  
occurs, press C to exit the menu.  
LIST  
Printing the Review Array. Press the LIST key  
to open the List menu. Select LASt (Last) to print  
LISt  
out the Review array, which consists of the last,  
dir  
maximum, and minimum values from the most  
LASt  
recent scan if the instrument configuration has  
not changed and the Review array has not been  
cleared.  
Press ENTER key to print the  
An  
measurements (see example below).  
Error  
ENTER  
ERROR message appears if the Review array is  
cleared (empty).  
Typical  
Required  
CANCL  
Time (Hours:Minutes:Seconds)  
of Last Recorded Scan  
Date (Month/Day/Year)  
of Last Recorded Scan  
16:51:47 07/21/94  
CH  
0:  
LAST VALUE  
399.74 HZ  
MAX VALUE  
415.63 HZ  
MIN VALUE  
392.22 HZ  
7: -013.91 VDC  
-013.88 VDC -013.95 VDC  
103.38 mVAC 103.35 mVAC  
004.74 MX+B 001.01 MX+B  
2.2666 kOHMS 2.2395 kOHMS  
12:  
103.38 mVAC  
001.07 MX+B  
2.2451 kOHMS  
072.34 F  
14:  
15:  
20:  
076.21 F  
071.29 F  
Channels  
Maximum Values  
Minimum Values  
Last Values  
op57f.eps  
Figure 5-4. Printing the Review Array  
5-8  
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Printer Operations  
Printing Measurement Data and Memory Card Directory  
5
Printing the Directory of the Memory Card  
Perform the procedure in Figure 5-5 to print the directory of the memory card files. The  
format is similar to a PC directory for a disk drive and will print any files that exist on  
the memory card.  
LIST  
Printing the Memory Card Directory. Press the  
LIST key to open the List menu; dir (Directory) is  
LISt  
selected to print out a directory of all the files on  
dir  
the memory card. Press ENTER to print the  
LASt  
directory (example below). If an Err 1 CArd  
message appears, this usually indicates a card  
is not inserted or the card is unformatted (see  
Table 3-1).  
Typical  
ENTER  
Required  
File Names  
Date (Month/Day/Year) File Created  
Time (Hours:Minutes) File Created  
SET00.HYD  
SET01.HYD  
SET02.HYD  
DAT00.HYD  
DAT01.HYD  
DAT02.HYD  
730 07-21-1994 08:23  
730 07-21-1994 11:16  
730 07-21-1994 16:53  
1460 07-21-1994 08:43  
1042 07-21-1994 12:48  
1250 07-21-1994 17:04  
6650 BYTES  
6 FILE(S)  
18586 BYTES FREE  
Size of  
File in Bytes  
Bytes Used and Bytes  
Free (Available)  
Total Number  
of Files  
op58f.eps  
Figure 5-5. Printing the Memory Card Directory  
5-9  
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2635A  
Users Manual  
5-10  
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Chapter 6  
Modem Operations  
Title  
Page  
Summary of Modem Operations ....................................................................... 6-3  
Connecting the Modem to a PC for Modem Configuration.............................. 6-4  
Configuring the Instrument Modem for Modem Operations ............................ 6-4  
Connecting the Modem to an Instrument .......................................................... 6-6  
Configuring the Instrument for Modem Operations.......................................... 6-7  
Testing the RS-232/Modem Interface ............................................................... 6-8  
6-1  
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2635A  
Users Manual  
HS AA CD OH RD TD TR MR  
REVIEW  
LAST  
HYDRA  
CH  
mA  
mVDCAC  
Hz  
M
k
V
COM  
REVIEW  
CLEAR  
FILES  
MODE  
INTVL  
SCAN  
CLOCK  
ALRM  
CANCEL  
FUNC  
Mx+B  
SINGLE  
300V  
MAX  
RATE  
MON  
TOTAL  
ZERO  
ENTER  
LIST  
SHIFT  
TRIGS  
COMM  
LOCAL  
BATT  
BUSY  
op84f.eps  
6-2  
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Modem Operations  
Summary of Modem Operations  
6
Summary of Modem Operations  
Modem operations allow an RS-232 connection between an instrument and a PC via  
modems and telephone lines, instead of a direct RS-232 connection as described in  
Chapter 4, "Computer Operations." Due to the wide variety of modems available and  
their corresponding software, only the most common connection using a Hayes-  
compatible modem using the AT command set is described. This connection can be  
adapted to any configuration, following the basic rules in each procedure. A typical  
overall connection diagram is shown in Figure 6-1.  
Hayes-compatible modems are both configured and controlled by commands from a PC.  
Since the Data Bucket does not have the capability to configure a modem, the modem is  
configured using a PC, then the PC is removed and the modem is connected to the Data  
Bucket. The modem operates in a simple answer mode since calls are never originated  
from the instrument. The modem configuration is stored in the modem memory. Some  
modems use an internal battery to prevent the erasure of the configuration if the modem  
power switch is turned off, while others lose all configuration when the power is turned  
off. Check the manual for your modem for an understanding of how the configuration is  
maintained.  
The information in this chapter is provided in five parts:  
Connecting the Modem to a PC for Configuration  
Configuring the Modem for Modem Operations  
Connecting the Modem to an Instrument  
Configuring the Instrument for Modem Operations  
Testing the RS-232/Modem Interface  
HYDRA  
PC  
HYDRA DATA BUCKET  
REVIEW  
LAST  
mA  
mVDCAC  
CH  
k
Hz  
COM  
V
INTVL  
FILES  
MODE  
REVIEW  
CLEAR  
300V  
MAX  
FUNC  
Mx+B  
ALRM  
CANCEL  
SCAN  
CLOCK  
RATE  
SINGLE  
MON  
ENTER  
SHIFT  
LIST  
TOTAL  
ZERO  
LOCAL  
COMM  
TRIGS  
BUSY BATT  
TELEPHONE LINES  
MODEM  
MODEM  
HS AA CD OH RD TD TR MR  
HS AA CD OH RD TD TR MR  
RS-232  
RS-232  
op59f.eps  
Figure 6-1. Overall PC-to-Instrument Modem Connection  
6-3  
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2635A  
Users Manual  
Connecting the Modem to a PC for Modem Configuration  
The two most common configurations for connecting the modem to a PC are shown in  
Figure 6-2. The modem RS-232 port (DB-25 connector) is cabled to a PC serial COM  
port that uses either a DB-9 connector or DB-25 connector. The connecting cable can be  
fabricated (See Appendix D) or ordered from Fluke as an option (see Chapter 1).  
Configuring the Instrument Modem for Modem Operations  
Commands to configure the modem are sent from the PC that is running  
communications software. The example below uses the Terminal mode that is available  
on any PC that is running Windows software. Modem operation at 2400 baud is assumed  
for this procedure, which should be adapted, as required.  
1. Start Windows and open TERMINAL on the ACCESSORIES menu.  
2. Open the SETTINGS menu and select COMMUNICATIONS.  
3. In COMMUNICATIONS, select the following, then use OK to exit to TERMINAL:  
Connector COM 1 [Typical]  
Baud Rate 2400  
Data Bits 8  
Stop Bits 1  
ParityNone  
Flow Control None  
4. In TERMINAL, enter a few AT <ENTER> character sequences. If the cable  
connection is correct and the modem has LED indicators, the data send and data  
receive indicator will blink. If LED blinking is not observed, check the cabling and  
verify that the correct PC COM port was selected in step 3.  
5. Enter the command ATV1 <ENTER>, which gives result codes in English, instead  
of numbers. For example, the AT <ENTER> characters entered in the last step  
would display the result code OK.  
6. Enter the command ATS0=1 <ENTER>, which configures the modem to answer  
calls after one ring. [The 0 character of the S0 portion of the command is the number  
zero.]Observe the result code OK.  
7. This completes the software configuration of the modem. Check all modem DIP  
switches for proper settings. In particular, some modems have a NO ANSWER  
switch that must be disabled or the modem will not answer calls. Be sure the modem  
remains powered or the configuration data could be lost. Refer to your modem  
manual, as required.  
6-4  
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Modem Operations  
Configuring the Instrument Modem for Modem Operations  
6
MODEM CONNECTION  
WITH PC DB-9  
CONNECTOR  
MODEM  
HS AA CD OH RD TD TR MR  
RS-232  
(DB-9)  
(MALE)  
RS-232 PORT  
(DB-25)  
(FEMALE )  
FLUKE RS41 CABLE  
(OR EQUAL)  
MODEM CONNECTION  
WITH PC DB-25  
CONNECTOR  
MODEM  
HS AA CD OH RD TD TR MR  
RS-232 PORT  
(DB-25)  
(FEMALE )  
RS-232 PORT  
(DB-25)  
DB-25 TO DB-9  
ADAPTER  
FLUKE RS41 CABLE  
(OR EQUAL)  
(MALE )  
op60f.eps  
Figure 6-2. Connecting the Modem to a PC  
6-5  
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2635A  
Users Manual  
Connecting the Modem to an Instrument  
Remove the cable from the PC and connect to the Data Bucket, as shown in Figure 6-3.  
If a different cable is used, be sure it is a modem cable.  
HYDRA  
MODEM  
HS AA CD OH RD TD TR MR  
FLUKE RS41 CABLE  
RS-232  
(DB-9)  
RS-232 PORT  
(DB-25)  
(OR EQUAL)  
(MALE)  
(FEMALE )  
op61f.eps  
Figure 6-3. Connecting the Modem to an Instrument  
6-6  
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Modem Operations  
Configuring the Instrument for Modem Operations  
6
Configuring the Instrument for Modem Operations  
Correct operation of the instrument RS-232/modem link depends on the baud rate,  
parity, CTS (Clear To Send), and Echo of the link parameters Perform the procedure in  
Figure 6-4 to establish the communication link parameters.  
SHIFT  
Selecting the bAUd (Baud) Rate. Press the  
SHIFT key, release, and then press the LIST key  
bAUd  
LIST  
to open the communications parameters menu.  
The baud rate sets the rate of data transfer  
between the instrument and the modem.  
Normally, the highest compatible rate is selected.  
Select the rate using the up/down arrow keys  
then press ENTER.  
38400  
19200  
9600  
4800  
2400  
1200  
600  
300  
ENTER  
ENTER  
ENTER  
ENTER  
Selecting PAR (Parity).  
The 8th bit of a  
PAR  
character can be set to make all characters odd  
(Odd) or even (E), or no parity at all (no). The  
PC checks parity (if selected) and indicates when  
an error is detected. Select the parity then press  
ENTER.  
no  
E
Odd  
Selecting CtS (Clear To Send). The RS-232  
CTS line is used to control data flow between the  
instrument and modem.  
applications, CTS is turned On. Make selection  
then press ENTER.  
CtS  
For most modem  
On  
OFF  
Selecting Echo. For this RS-232 application,  
Echo OFF is selected. When modem operations  
are initiated, any characters sent from the  
instrument to the modem before the modem has  
experienced "carrier detect" will cause the  
modem to suddenly disconnect from the line.  
Echo  
On  
OFF  
Typical  
Required  
op62f.eps  
Figure 6-4. Configuring the Instrument RS-232 Port for Modem Operations  
6-7  
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2635A  
Users Manual  
Testing the RS-232/Modem Interface  
The PC end of the modem link involves a similar procedure of connecting the correct  
cable between the PC and modem, and configuring the modem to support the  
communications link. This is the responsibility of the user due to the variety of available  
modems and software. Be sure the PC COM port has the same parameters as those  
selected in Figure 6-4.  
When all connections and configurations are complete, the PC should initiate  
communications with the modem supporting the instrument using the selected  
communications software. Typically, this means selecting a dial feature, or entering an  
AT command, e.g., ATDT 123-4567 from the terminal emulation screen. After the  
connection is made and the terminal emulation screen is present, enter a few <ENTER>  
characters to clear the instrument buffer, and note the instrument => prompts on the  
screen. Then enter the command *IDN? <ENTER> (since ECHO OFF was selected in  
Figure 6-4, the *IDN? characters will not appear on screen). The return should be  
FLUKE,2635A,0,Mn.n An.n Dn.n Ln.n where n.n is replaced with the versions of the  
displayed parameters. (See the *IDN? command in Chapter 4 for more information.)The  
RS-232/modem link is operating correctly and the PC may now operate using Starter or  
Logger applications software, or custom software.  
Problems?  
If the modem does not operate after making the RS-232 connection, telephone line  
connections, and setting the instrument and PC parameters, check the following:  
1. No operation of any kind usually indicates a cabling problem, hardware  
incompatibility, a modem DIP switch problem, or incorrectly selecting ECHO ON in  
Figure 6-4 (ECHO OFF must be selected).  
2. Incorrect operation usually indicates a configuration incompatibility, i.e., the  
instrument and PC baud rate and parity dont match.  
3. Verify the modem configuration data hasnt been lost or corrupted. Some modems  
use an internal battery to retain configuration data when power is removed, and some  
modems lose configuration data if power is removed. If the configuration data is  
suspect, repeat the configuration procedures in this chapter.  
6-8  
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Chapter 7  
Maintenance  
Title  
Page  
Introduction ....................................................................................................... 7-3  
Cleaning............................................................................................................. 7-3  
Line Fuse ........................................................................................................... 7-3  
Selftest Diagnostics and Error Codes................................................................ 7-4  
Performance Tests............................................................................................. 7-4  
Accuracy Verification Test........................................................................... 7-7  
Channel Integrity Test................................................................................... 7-8  
Thermocouple Measurement Range Accuracy Test ..................................... 7-9  
Four-Terminal Resistance Test..................................................................... 7-10  
Thermocouple Temperature Accuracy Test.................................................. 7-10  
Open Thermocouple Response Test ............................................................. 7-11  
RTD Temperature Accuracy Test................................................................. 7-13  
RTD Temperature Accuracy Test (Using Decade Resistance Source).... 7-13  
RTD Temperature Accuracy Test (Using DIN/IEC 751 RTD)................ 7-14  
Digital Input/Output Verification Tests........................................................ 7-15  
Digital Output Test ................................................................................... 7-15  
Digital Input Test...................................................................................... 7-16  
Totalizer Test............................................................................................ 7-17  
Totalizer Sensitivity Test.......................................................................... 7-18  
Dedicated Alarm Output Test ....................................................................... 7-18  
External Trigger Input Test........................................................................... 7-21  
Calibration......................................................................................................... 7-21  
Variations in the Display................................................................................... 7-22  
Service............................................................................................................... 7-22  
7-1  
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2635A  
Users Manual  
AC MEASUREMENT  
STANDARD  
5790A  
CALIBRATOR  
DATA BUCKET  
REVIEW  
LAST  
HYDRA  
CH  
mA  
mVDCAC  
Hz  
M
k
V
COM  
REVIEW  
CLEAR  
FILES  
MODE  
INTVL  
SCAN  
CLOCK  
ALRM  
CANCEL  
FUNC  
Mx+B  
SINGLE  
300V  
MAX  
RATE  
MON  
TOTAL  
ZERO  
ENTER  
LIST  
SHIFT  
TRIGS  
COMM  
LOCAL  
BATT  
BUSY  
op85f.eps  
7-2  
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Maintenance  
Introduction  
7
Introduction  
This chapter describes basic maintenance that the instrument user can perform. Do not  
attempt any maintenance not described in this chapter. For additional maintenance,  
service, and calibration procedures, qualified service personnel can refer to the Hydra  
Series II Service Manual (part number 688868).  
Cleaning  
WWarning  
Keep the instrument dry to avoid electrical shock to personnel  
or damage to the instrument. To prevent damage, never apply  
solvents to the instrument housing.  
For cleaning, wipe the instrument with a cloth that is lightly dampened with water or  
mild detergent. Do not use aromatic hydrocarbons, chlorinated solvents, or methanol-  
based fluids.  
Line Fuse  
The instrument uses a type "T" 125 mA, 250V (Slow blow) line fuse in series with the  
power supply. To replace this fuse (located on the rear panel), unplug the line cord and  
remove the fuse holder with the fuse as shown in Figure 7-1. The instrument is shipped  
with a replacement fuse secured in the fuse holder.  
Power-Line Cord Connector  
To Remove,  
Squeeze and  
Slide Out  
+
0
1
2
3
9-16 V  
DC PWR  
DIGITAL I/O  
3
T
R
+30V  
0
1
2
!
Complies with the limit for a class B computing device  
pursuant to Subpart J of 5 of FC  
MEETS 40P8a7r1t 1B  
5
6
C Rul7es  
Σ
Line Fuse  
(T 125 mA, 250V,  
Slow Blow)  
Fuse Holder  
(Spare Fuse Provided)  
op63f.eps  
Figure 7-1. Replacing the Line Fuse  
7-3  
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2635A  
Users Manual  
Selftest Diagnostics and Error Codes  
When the instrument is powered up, the entire display lights.  
Note  
To hold the display fully lit, press and hold the K key, then press R  
ON and wait a moment for the instrument to beep. Then release K. The  
entire display will now stay on until you press any button; the power-up  
sequence then resumes.  
Selftest diagnostics are performed each time the instrument is powered up. Any errors  
encountered during this initial 4-second period are displayed momentarily. Even in the  
presence of an error, the instrument still attempts to complete the selftest routine and  
begin normal operation.  
An error indicates that a malfunction has occurred and maintenance is required. If you  
encounter an error, note the number or letter and consult Table 7-1. See if the instrument  
repeats the error. If the problem persists and you intend to repair the instrument yourself,  
refer to the Service Manual. Otherwise, package the instrument securely (using the  
original container if available.) Then forward the package, postage paid, to the nearest  
Fluke/Philips Service Center. Include a description of the problem. Fluke assumes no  
responsibility for damage in transit.  
Performance Tests  
When received, the 2635A Hydra Series II is calibrated and in operating condition. The  
following Performance Verification Procedures are provided for acceptance testing upon  
initial receipt or to verify correct instrument operation. All tests may be performed in  
sequence to verify overall operation, or the tests may be run independently.  
If the instrument fails a performance test, calibration adjustment and/or repair is needed.  
To perform these tests, you will need a Fluke 5700A Multifunction Calibrator or  
equipment meeting the minimum specifications given in Table 7-2.  
Table 7-1. Power-Up Error Codes  
Error  
Description  
Boot ROM checksum error  
1
2
3
4
5
6
7
8
9
A
b
C
d
Instrument ROM checksum error  
Internal RAM test failed  
Display power-up test failure  
Display not responding  
Instrument configuration corrupted  
instrument calibration data corrupted  
Instrument not calibrated  
A/D converter not responding  
A/D converter ROM test failure  
A/D converter RAM test failure  
A/D converter selftest failed  
Memory Card interface not installed  
7-4  
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Maintenance  
Performance Tests  
7
Each of the measurements listed in the following steps assume the instrument is being  
tested after a 1/2 hour warmup, in an environment with an ambient temperature of 18 to  
28ºC, and a relative humidity of less than 70%.  
Note  
All measurements listed in the performance test tables are made in the slow  
reading rate unless otherwise noted.  
W Warning  
The 2635A instrument contains high voltages that can be  
dangerous or fatal. Only qualified personnel should attempt to  
service the instrument.  
7-5  
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2635A  
Users Manual  
Table 7-2. Recommended Test Equipment  
Minimum Specification  
Instrument Type  
Recommended  
Model  
Multifunction Calibrator  
DC Voltage:  
Fluke 5700A  
Range: 90 mV to 300V dc  
Accuracy: .005%  
AC Voltage:  
Frequency  
1 kHz  
Voltage  
Accuracy  
0.05%  
29 mV to 300V  
15 mV to 300V  
100 kHz  
Frequency:  
10 kHz  
1.25%  
1V rms  
.0125%  
Decade Resistance  
Source  
General Resistance  
Inc. Model RDS 66A  
Ohms  
Accuracy  
290  
2.9 kΩ  
29 kΩ  
0.0125%  
0.0125%  
0.0125%  
0.0125%  
0.0125%  
290 kΩ  
2.9 MΩ  
Note  
The 5700A Calibrator provides 0.05% accuracy  
(rated) on the 3.0 k, 30 k, 300 ke and 3.0  
Mranges. The 5700A can be used for 0.06%  
accuracy on the 300range.  
Mercury Thermometer  
Thermocouple Probe  
0.02 degrees Celsius resolution  
Type T  
Princo ASTM-56C  
Fluke P-20T  
Room Temperature  
Oil/Water Bath  
Thermos bottle and cap  
Multimeter  
Measures +5V dc  
Fluke 77  
Signal Generator  
Sinewave, 0.5 to 1V rms 10 Hz to 5 kHz  
Alternate Equipment List  
Fluke 6011A  
(Minimum specifications are the same as in the Standard Equipment List)  
Instrument Type Recommended Model  
DC Voltage Calibrator  
Fluke 5700A  
DMM Calibrator  
Fluke 5100B (for AC Volts only)  
Philips PM5193 or Fluke 6011A  
Gen Rad 1433H  
Function/Signal Generator  
Decade Resistance Source  
7-6  
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Maintenance  
Performance Tests  
7
Accuracy Verification Test  
1. Power up the instrument and allow the temperature to stabilize for 30 minutes.  
2. Connect a cable from the Output VA HI and LO connectors of the 5700A to the V  
and COM connectors on the front panel of the Hydra Series II. Select the channel 0  
function and range on the Hydra Series II and the input level from the 5700A using  
the values listed in Table 7-3. Press the M (monitor) button to measure and display  
the measurement value for channel 0. The display should read between the minimum  
and maximum values listed in the table.  
Table 7-3. Performance Tests (Voltage, Resistance, and Frequency)  
DISPLAY ACCURACY  
FUNCTION  
RANGE  
INPUT LEVEL  
FREQUENCY  
(1 Year, 18-28°C)  
MIN  
MAX  
DC Volts  
90 mV  
90 mV  
300 mV  
300 mV  
300 mV  
3V  
short (0)  
90 mV  
0V  
--  
-0.006  
89.972  
-0.02  
0.006  
--  
90.028  
0.02  
--  
150 mV  
290 mV  
2.9V  
--  
149.94  
289.91  
2.8991  
-2.9009  
28.991  
149.94  
289.91  
150.06  
290.09  
2.9009  
-2.8991  
29.009  
150.06  
290.09  
--  
--  
-3V  
-2.9V  
29V  
--  
30V  
-
150V  
300V  
150V  
290V  
--  
--  
NOTE  
Voltages greater than 150V can only be applied to channels 0,1, and 11.  
AC Volts  
300 mV  
300 mV  
300 mV  
3V  
20 mV  
20 mV  
290 mV  
290 mV  
2.9V  
1 kHz  
100 kHz  
1 kHz  
19.71  
18.50  
20.29  
21.50  
289.28  
275.00  
2.8937  
28.931  
149.54  
289.34  
290.72  
305.00  
2.9063  
29.069  
150.46  
290.66  
100 kHz  
1 kHz  
3V  
30V  
29V  
1 kHz  
150V  
300V  
150V  
1 kHz  
290V  
1 kHz  
NOTE  
Voltages greater than 150V can only be applied to channels 0, 1, and 11. The rear Input Module must  
be installed when measuring ac volts on channel 0.  
NOTE  
For 2-terminal measurements, the resistance accuracy given in this table applies to Channel 0 and  
makes allowance for up to 0.05 ohm of lead wire resistance. You must add any additional lead wire  
resistance present in your set up to the resistance values given in this table.  
Resistance  
Using inputs in decades of 3:  
300 e  
short  
300e  
short  
0.00  
0.09  
299.90  
0.0000  
2.9989  
29.990  
299.88  
2.9979  
300.15  
0.0003  
3.0011  
30.010  
300.12  
3.0021  
3 ke  
3 ke  
30 ke  
300 ke  
3 Me  
30 ke  
300 ke  
3 Me  
7-7  
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2635A  
Users Manual  
Table 7-3. Performance Tests (Voltage, Resistance, and Frequency) (cont)  
Using inputs in decades of 1.9:  
300 e  
short  
190 e  
short  
0.00  
0.09  
189.93  
0.0000  
1.8992  
18.992  
189.91  
1.8983  
190.12  
0.0003  
1.9008  
19.008  
190.09  
1.9017  
3 ke  
1.9 ke  
19 ke  
190 ke  
1.9 Me  
30 ke  
300 ke  
3 Me  
Using inputs in decades of 1:  
300 e  
short  
0.00  
99.95  
0.0000  
0.9995  
9.995  
99.94  
0.9990  
9.979  
0.09  
100 e  
100.10  
0.0003  
1.0006  
10.005  
100.06  
1.0010  
10.021  
3 ke  
short  
1 ke  
30 ke  
300 ke  
3 Me  
10 ke  
100 ke  
1 Me  
10 Me*  
10 Me  
*Optional test point if standards available.  
NOTE  
All channels (0 through 20) can accommodate 2-terminal resistance measurements. Channel 0, with  
only two connections, cannot be used for 4-terminal measurements. Four-terminal resistance  
measurements can be defined for channels 1 through 10 only. Channels 11 through 20 are used, as  
required, for 4-terminal to provide the additional two connections. For example, a 4-terminal set up on  
channel 1 uses channels 1 and 11, each channel providing two connections.  
Frequency  
90 kHz/2V  
p-p  
10kHz  
9.994  
10.006  
Channel Integrity Test  
Ensure that the Accuracy Verification Test for channel 0 meets minimum acceptable  
levels before performing this test.  
1. Switch OFF power to the instrument and disconnect all high voltage inputs.  
2. Remove the Input Module from the rear of the instrument. Open the Input Module  
and connect a pair of test leads to the H (high) and L (low) terminals of channel 1.  
Reinstall the Input Module into the instrument.  
3. Connect the ends of the test leads together to apply a short (0 ohms).  
4. Reconnect power and switch the instrument ON.  
7-8  
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Maintenance  
Performance Tests  
7
5. For channel 1, select the two-terminal ohms function and 300 ohms range on the  
Hydra Series II. Press M and ensure the display reads a resistance of less than or  
equal to 4.0 ohms. (This test assumes that lead wire resistances are less than 0.1.)  
6. Open the ends of the test leads and ensure that the display reads OL" (overload).  
7. Press M.This will stop the measurement.  
8. Connect a cable from the Output VA HI and LO of the 5700A to the Input Module  
test leads (observe proper polarity).  
9. Select the VDC function and 300 volt range on the Hydra Series II and first apply  
0V dc then 290V dc input from the 5700A. Ensure the display reads between the  
minimum and maximum values as shown in Table 7-3 for the 0 and 290V dc input  
levels.  
Note  
Channels 0, 1, and 11 have a maximum input of 300V dc or ac (rms). The  
maximum input for all other channels is 150V dc or ac (rms).  
10. With the exception of the selected voltage range and input voltage from the 5700A,  
repeat steps 1 through 9 for each remaining Input Module channel (2 through 20).  
Channels 2 through 10 and 12 through 20 should be configured for the 150V dc  
range and an input voltage of 150 volts.  
Thermocouple Measurement Range Accuracy Test  
Ensure that the Accuracy Verification Test for channel 0 meets minimum acceptable  
levels before performing this test.  
Thermocouple temperature measurements are accomplished using Hydra Series IIs 90  
mV and internal 900 mV dc ranges. (The 900 mV range is not configurable from the  
instrument front panel.) This procedure will provide the means to test these ranges.  
Testing the 900 mV dc range requires computer interfacing with a host (terminal or  
computer). The host must send commands to select this range. This range cannot be  
selected from the Hydra Series II front panel.  
1. Ensure that communication parameters ( i.e., transmission mode, baud rate, parity,  
CTS, and echo mode) on the Hydra Series II and the host are properly configured to  
send and receive serial data. Refer to Chapter 4 "Computer Operations."  
2. Power up Hydra Series II and allow the temperature to stabilize for 30 minutes.  
3. Connect a cable from the Output VA HI and LO connectors of the 5700A to the VΩ  
and COM connectors on the front panel of the Hydra Series II.  
4. Set the 5700A to output 0V dc.  
5. Using either a terminal or a computer running a terminal emulation program as the  
selected host, send the following commands to Hydra Series II:  
FUNC 0,VDC,5 <CR>  
MON 1,0 <CR>  
MON_VAL? <CR>  
The returned value for channel 0 should be 0 mV ±0.006 mV.  
Set the 5700A to output 90 mV DC. Send the following command:  
MON_VAL? <CR>  
7-9  
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2635A  
Users Manual  
The value returned should now be 90 mV ±0.028 mV (between 89.97 and  
90.028 mV).  
6. Change Hydra Series II's channel 0 function to the internal 900 mV dc range by  
redefining channel 0. Send the following commands:  
MON 0 <CR>  
FUNC 0,VDC,6 <CR>  
Set the 5700A to output 0.9V dc. Send the following commands:  
MON 1,0 <CR>  
MON_VAL? <CR>  
The value returned should be 900 mV ±0.21 mV (899.79 to 900.21mV.)  
Four-Terminal Resistance Test  
Ensure that Channel 0's Accuracy Verification Test for DC Volts and Resistance meets  
minimum acceptable levels.  
1. Switch OFF power to the instrument and disconnect all high voltage inputs.  
2. Remove the Input Module from the rear of the instrument. Open the Input Module  
and connect a pair of test leads (keep as short as possible) to the H (high) and L  
(low) terminals of channel 1, and connect a second pair of test leads to the H and L  
terminals of channel 11. Reinstall the Input Module into the instrument.  
3. Observing polarity connect channel 1's test leads to the Sense HI and LO terminals  
of the 5700A, and connect channel 11's test leads to the Output HI and LO terminals  
of the 5700A. Connect as shown in Figure 7-2.  
4. Switch the instrument ON.  
5. Select the Four-terminal OHMS function, AUTO range, for channel 1 on the Hydra  
Series II.  
6. Set the 5700A to output the resistance values listed in Table 7-3 (Use decades of  
1.9).  
7. On Hydra Series II press M and ensure the display reads between the minimum  
and maximum values shown on Table 7-3.  
8. The Four-terminal Resistance Test is complete. However, if you desire to perform  
this test on Input Module channels (2 through 10), repeat steps 1 through 7,  
substituting the appropriate channel number.  
Note  
Four-Terminal connections are made using pairs of channels. Four-  
terminal measurements can be made only on channels 1 though 10 (n). The  
accompanying pairs are channels 11 through 20 (n+10).  
Thermocouple Temperature Accuracy Test  
Ensure that the Thermocouple Measurement Range Accuracy Test meets minimum  
acceptable levels before performing this test.  
1. Switch OFF power to the instrument and disconnect all high voltage inputs.  
2. Remove the Input Module from the rear of the instrument. Open the Input Module  
and connect a T-type thermocouple to the H (blue lead) and L (red lead) terminals of  
channel 1. Reinstall the Input Module into the instrument.  
7-10  
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Maintenance  
Performance Tests  
7
Note  
If other than a T-type thermocouple is used, be sure that the instrument is  
set up for the type of thermocouple used.  
3. Reconnect power and switch the instrument ON.  
4. Insert the thermocouple and a mercury thermometer in a room temperature bath.  
Allow 20 minutes for thermal stabilization.  
5. Select the temperature and T-type thermocouple function for channel 1.Press M.  
6. The value displayed should be the temperature of the room temperature bath as  
measured by the mercury thermometer (within tolerances given in Table 7-4, plus  
any sensor inaccuracies.).  
7. The Thermocouple Temperature Accuracy Test is complete. However, if you desire  
to perform this test on any other Input Module channel (2 through 20), repeat steps 1  
through 6, substituting the appropriate channel number.  
Open Thermocouple Response Test  
1. Switch OFF power to the instrument and disconnect all high voltage inputs.  
2. Remove the Input Module from the rear of the instrument. Open the Input Module  
and connect test leads to the H (high) and L (low) terminals of channel 1. Reinstall  
the Input Module into the instrument.  
Table 7-4. Performance Tests for Thermocouple Temperature Function (ITS-90)  
Thermocouple Type  
Thermocouple Accuracy Specifications 1 Year  
@ 18-28 Degrees C  
J
K
N
E
T
±0.40°C  
±0.44°C  
±0.53°C  
±0.38°C  
±0.45°C  
1. Reconnect power and switch the instrument ON.  
2. Connect the test leads from the Input Module to an 820 ohm resistor.  
3. Select the temperature and T-type thermocouple function for channel 1.Press M.  
4. The value displayed should approximate the ambient temperature.  
5. Replace the 820 ohm resistor with a 4 kilohm resistor to simulate a high resistance or  
open thermocouple.  
6. Verify a reading of "otc".  
7. The Open Thermocouple Response Test is complete. However, if you desire to  
perform this test on any other Input Module channel (2 through 20), repeat steps 1  
through 8, substituting the appropriate channel number.  
7-11  
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2635A  
Users Manual  
11 12 13 14 15 16 17 18 19 20  
H L H L H L H L H L H L H L H L H L H L  
SOURCE  
(4-WIRE)  
HYDRA  
INPUT  
MODULE  
H L H L H L H L H L H L H L H L H L H L  
SENSE  
(4-WIRE)  
1
2
3
4
5
6
7
8
9
10  
5700A  
OUTPUT  
SENSE  
V
A
V
WIDEBAND  
HI  
HI  
LO  
HI  
LO  
AUX  
CURRENT  
ARD  
GROUND  
NC  
NC  
2-WIRE  
COMP  
OFF  
: ON  
: OFF  
EX SNS  
EX GRD  
SENSE  
SOURCE  
UUT  
5700A  
SOURCE  
SENSE  
op64f.eps  
Figure 7-2. Four-Terminal Connections to 5700A  
7-12  
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Maintenance  
Performance Tests  
7
RTD Temperature Accuracy Test  
The following two RTD Temperature Accuracy Tests are different in that one test uses a  
Decade Resistance Source and the other uses an RTD. Only one of the tests need to be  
performed to assure operation.  
RTD Temperature Accuracy Test (Using Decade Resistance Source)  
Ensure that Channel 0s Accuracy Verification Test for DC Volts and 300 Ohm  
Resistance Range meets minimum acceptable levels.  
1. Switch OFF power to the instrument and disconnect all high voltage inputs.  
2. Remove the Input Module from the rear of the instrument. Open the Input Module  
and connect a pair of test leads (keep as short as possible) to the H (high) and L  
(low) terminals of channel 1. For Four-terminal performance testing, connect a  
second pair of test leads to the H (high) and L (low) terminals of channel 11.  
Reinstall the Input Module into the instrument.  
3. Connect channel 1s test leads to the Output HI and LO terminals of the Decade  
Resistance Source. For Four-terminal performance testing, also connect channel 11s  
test leads to the Output HI and LO terminals of the Decade Resistance Source.  
Connect as shown in Figure 7-3.  
Note  
Four-terminal connections are made using pairs of channels. Four-  
terminal measurements can be made only on channels 1 though 10 (n). The  
accompanying pairs are channels 11 through 20 (n+10).  
4. Switch the instrument ON.  
5. Select the Four-terminal RTD temperature function, RTD type PT, for channel 1 on  
the Hydra Series II. Press M, select a Decade Resistance value, and ensure the  
display reads between the minimum and maximum values shown on Table 7-5.  
6. The RTD Temperature Accuracy test is complete. However if you desire to perform  
this test on Input Module channels (2 through 10), repeat steps 1 through 5,  
substituting the appropriate channel number.  
Note  
The only type of temperature measurement that can be made on channel 0  
is two-terminal RTD. Channels 11 through 20 will support only two-  
terminal RTDs.  
7-13  
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2635A  
Users Manual  
4-WIRE (4T) CONNECTION  
11 12 13 14 15 16 17 18 19 20  
H L H L H L H L H L H L H L H L H L H L  
SOURCE  
(4-WIRE)  
HYDRA  
INPUT  
MODULE  
H L H L H L H L H L H L H L H L H L H L  
SENSE  
(4-WIRE)  
1
2
3
4
5
6
7
8
9
10  
DECADE  
RESISTANCE  
BOX  
op65f.eps  
Figure 7-3. Four-Terminal Connections to Decade Resistance Box  
Table 7-5. Performance Tests for RTD Temperature Function (Resistance Source) (DIN/IEC 751  
Amendment 2) (ITS-90)  
DECADE RESISTANCE  
SOURCE  
TEMPERATURE SIMULATED  
TEMPERATURE ACCURACY  
1 YEAR @ 18-28°C  
°C  
100 e  
200 e  
300 e  
0
± 0.12°C  
± 0.22°C  
± 0.37°C  
266.35  
557.69  
These figures assume that RTD R0 is set to 100.00 ohms for each channel.  
Accuracy given is for 4-wire measurements only. For 2-wire measurements, degrade the accuracy  
specifications by 5.2 °C per ohm of single lead wire resistance. For 2-wire measurements, degrade the  
accuracy by an additional 11°C (channels 1 .. 20)or 0.05°C (channel 0).  
RTD Temperature Accuracy Test (Using DIN/IEC 751 RTD)  
1. Switch OFF power to the instrument and disconnect all other high voltage inputs.  
2. Remove the Input Module from the rear of the instrument. Open the Input Module  
and connect a Platinum RTD, conforming to the European Standards IEC 751 (DIN  
43760).  
Two-terminal RTD: Connect the RTDs excitation leads to the H (high) and L (low)  
terminals of channel 1.  
Four-terminal RTD: Connect the RTDs excitation leads (one red and one black  
wire) to the H (high) and L (low) terminals of channel 1. Connect the RTDs second  
pair of red and black leads to the H and L leads of channel 11. (Refer to Figure 7-3  
for proper connection.) Reinstall the Input Module into the instrument.  
7-14  
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Maintenance  
Performance Tests  
7
Note  
Four-terminal connections are made using pairs of channels. Four-  
terminal measurements can be made only on channels 1 though 10 (n).  
Their accompanying pairs are channels 11 through 20 (n+10).  
3. Switch the instrument ON.  
4. Insert the RTD probe and a mercury thermometer in a room temperature bath. Allow  
20 minutes for thermal stabilization.  
5. Dependent on the type of connection made in step 2, select either the two-terminal or  
four-terminal RTD temperature function, RTD type PT (DIN/IEC 751), for channel  
1 on the Hydra Series II. Press M and ensure the display reads the temperature of  
the room temperature bath (within tolerances shown in Table 7-6) as measured by  
the mercury thermometer.  
6. The RTD Temperature Accuracy test is complete. However if you desire to perform  
this test on any other channel (0 or 2 through 20) repeat steps 1 through 5  
substituting the appropriate channel number.  
Note  
The only type of temperature measurement that can be made on channel 0  
is two-terminal RTD. Channels 11 through 20 will support only two-  
terminal RTDs.  
Table 7-6. Performance Tests for RTD Temperature Function (DIN/ IEC 751 Amendment 2)(ITS-90)  
RTD TYPE  
TEMPERATURE ACCURACY  
SPECIFICATIONS 1 YEAR @ 18-28°C  
2-wire (channel 0)  
-0.54°C to 0.59°C  
-0.54°C to 11.54°C  
±0.54°C  
2-wire (channels 1-20)  
4-wire  
Assumes RTD R0 is set to 100.00 e for each channel.  
Digital Input/Output Verification Tests  
Digital Input/Output verification testing requires computer interfacing with a host  
(terminal or computer). The host must send commands to the instrument to control the  
digital lines for this test. Refer to Chapter 4 for a description of configuring and  
operating the instrument.  
Digital Output Test  
1. Ensure that communication parameters ( i.e., transmission mode, baud rate, parity,  
CTS, and echo mode) on the Hydra Series II and the host are properly configured to  
send and receive serial data. Refer to Chapter 4.  
2. Switch OFF power to the instrument and disconnect all high voltage inputs.  
3. Remove the Digital I/O ten terminal connector from the rear of the instrument and  
all external connections to it. Connect short wires (to be used as test leads) to the  
GROUND and 0 through 7 terminals. Leave the other wire ends unconnected at this  
time. Reinstall the connector.  
4. Switch power ON to both Hydra Series II and the host. Verify that Hydra Series II is  
not scanning. If Hydra Series II is scanning, press Q to turn scanning off, then  
cycle power off-on again.  
7-15  
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2635A  
Users Manual  
5. Using a digital multimeter (DMM), verify that all digital outputs (0-7) are in the  
OFF or HIGH state. This is done by connecting the low or common of the  
multimeter to the ground test lead and the high of the multimeter to the digital output  
and verifying a voltage greater than +3.8V dc.  
6. Using either a terminal or a computer running a terminal emulation program, set up  
Hydra Series II to turn Digital Outputs ON (LOW state).  
In sequence send the following commands to Hydra Series II and measure that the  
correct Digital Output line transitioned LOW measures less than+0.8V dc.  
DO_LEVEL 0,0 <CR>  
Ensure that output 0 measures a LOW state.  
DO_LEVEL 1,0 <CR>  
Ensure that output 1 measures a LOW state.  
DO_LEVEL 2,0 <CR>  
Ensure that output 2 measures a LOW state.  
Repeat the command for all eight outputs.  
7. Set up Hydra Series II to turn Digital Outputs OFF (HIGH state).  
In sequence send the following commands to Hydra Series II and measure that the  
correct Digital Output line transitioned HIGH measures greater than +3.8V dc.  
DO_LEVEL 0,1 <CR>  
Ensure that output 0 measures a HIGH state.  
DO_LEVEL 1,1 <CR>  
Ensure that output 1 measures a HIGH state.  
Repeat the command for all eight outputs.  
Digital Input Test  
1. Perform the DIGITAL OUTPUT TEST steps 1 through 5.  
2. Using either a terminal or a computer running a terminal emulation program, set up  
Hydra Series II to read the Digital Input lines.  
Send the following command to Hydra Series II:  
DIO_LEVELS? <CR>  
Verify that the returned value is 255.  
Note  
The number returned is the decimal equivalent of the Digital Input binary  
word (inputs 0 through 7s status). See Table 7-7 to determine if the  
number returned corresponds to the bits jumpered to ground in this test.  
3. Jumper input 0 to ground by connecting the ground test lead to input 0s test lead.  
Then send the following command to Hydra Series II:  
DIO_LEVELS? <CR>  
Verify that the returned value is 254.  
4. Disconnect input 0 from ground then jumper input 1 to ground.  
7-16  
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Maintenance  
Performance Tests  
7
Send the command: DIO_LEVELS? <CR>  
Verify the returned value is 253.  
5. Repeat step 4 for each input and verify the correct returned value (See Table 7-7).  
Table 7-7. Digital Input Values  
TERMINAL GROUNDED  
STATE OF DIGITAL INPUTS  
inputs 0-7, all HIGH  
DECIMAL VALUE  
none  
255  
254  
253  
251  
247  
239  
223  
191  
127  
0
1
2
3
4
5
6
7
inputs 1-7 HIGH, input 0 LOW  
inputs 0,2-7 HIGH, input 1 LOW  
inputs 0-1 and 3-7 HIGH, input 2 LOW  
inputs 0-2 and 4-7 HIGH, input 3 LOW  
inputs 0-3 and 5-7 HIGH, input 4 LOW  
inputs 0-4 and 6-7 HIGH, input 5 LOW  
inputs 0-5 and 7 HIGH, input 6 LOW  
inputs 0-6 HIGH, input 7 LOW  
Totalizer Test  
This totalizer verification test requires toggling the Digital Output line 0 and using it as  
the Total input. The test requires computer interfacing with a host (terminal or  
computer). The host must send commands to the 2635A instrument to control the digital  
line for this test. Refer to Chapter 4 for a description of configuring and operating Hydra  
Series II.  
1. Ensure that communication parameters ( i.e., transmission mode, baud rate, parity,  
CTS, and echo mode) on Hydra Series II and the host are properly configured to  
send and receive serial data. Refer to Chapter 4.  
2. Switch OFF power to the instrument and disconnect all high voltage inputs.  
3. Remove the Digital I/O ten-terminal connector from the rear of the instrument and  
all external connections to it. Connect short wires (to be used as test leads) to the  
DIGITAL I/O terminal 0 and the Total (SUM) terminal. Leave other ends of wires  
unconnected at this time. Reinstall the connector.  
4. Switch ON power to both Hydra Series II and the host.  
5. Press the O button on the front panel of Hydra Series II.  
Ensure that Hydra Series II displays a 0 value.  
6. Jumper the DIGITAL I/O terminal 0 to the Total (SUM) input by connecting the  
(SUM) terminal test lead to DIGITAL I/O 0s test lead.  
7. Using either a terminal or a computer running a terminal emulation program, set up  
Hydra Series II to toggle (turn ON and OFF) Digital Output 0.  
In sequence send the following commands to Hydra Series II and ensure that Hydra  
Series II measures and displays the correct total value:  
DO_LEVEL 0,0 <CR>  
DO_LEVEL 0,1 <CR>  
Ensure that Hydra Series II displays a totalizer count of 1.  
7-17  
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2635A  
Users Manual  
8. Again in sequence, send the commands:  
DO_LEVEL 0,0 <CR>  
DO_LEVEL 0,1 <CR>  
Hydra Series II should now display a totalizer count of 2.  
9. Repeat step 8 for each incremental totalizing count.  
10. Set the Hydra Series IIs totalized count to a value near full range (65535) and test  
for overload.  
Send the following commands to Hydra Series II:  
TOTAL 65534 <CR>  
DO_LEVEL 0,0 <CR>  
DO_LEVEL 0,1 <CR>  
A totalizer count of 65535 should be displayed.  
11. Send:  
DO_LEVEL 0,0 <CR>  
DO_LEVEL 0,1 <CR>  
Hydra Series IIs display should now read "OL". This indicates that the counter has  
changed from its maximum count (65535) to zero (0) and has set the Totalize  
Overflow bit in the Instrument Event Register.  
Totalizer Sensitivity Test  
1. Perform the Totalizer Test and ensure that it is operational.  
2. Remove the jumper connecting the (SUM) terminal test lead to output 0s test lead.  
3. Ensure that Hydra Series II is still in the totalize display mode. If not, press the O  
button. Reset the totalizer count shown on the display by pressing Hydra Series IIs  
front panel K button followed by O (ZERO) button.  
Hydra Series IIs display should now show a value of 0.  
4. Connect the output of the signal generator to the SUM and GROUND terminals.  
5. Program the signal generator to output a 1.5V rms sine signal at 10 Hz.  
Hydra Series IIs display should now show the totalizing value incrementing at a 10  
count per second rate.  
Dedicated Alarm Output Test  
The Dedicated Alarm Output Test verifies that Alarm Outputs 0 through 3 are  
functioning properly. Because this test is dependent on voltage readings, the Accuracy  
Verification Test for channel 0 and the Channel Integrity Test for channels 1 through 3  
should be performed if voltage readings are suspect.  
1. Switch OFF power to the instrument and disconnect all high voltage inputs.  
2. Remove the Alarm Output eight-terminal connector module from the rear of Hydra  
Series II and all external connections to it. Connect short wires (to be used as test  
leads) to the GROUND and 0 through 3 terminals. Leave other ends of wires  
unconnected at this time. Reinstall the connector.  
7-18  
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Maintenance  
Performance Tests  
7
3. Remove the Input Module from the rear of Hydra Series II. Open the Input Module  
and jumper the H (high) terminal of channels 1, 2, and 3 together. Connect a test  
lead to the H of channel 1. Also jumper the L (low) terminals of channel 1, 2, and 3  
together. Connect a second test lead to the L of channel 1. Reinstall the Input  
Module into Hydra Series II. Refer to Figure 7-4.  
4. Switch power ON.  
5. Using a digital multimeter (DMM), verify that alarm outputs 0 through 3 are in the  
OFF or HIGH state. Perform this test by connecting the low or common of the  
multimeter to the ground test lead and the high of the multimeter to the alarm output.  
Verify a voltage greater than +3.8V dc.  
6. Connect a cable from the Output VA HI and LO connectors of the 5700A to the VΩ  
and COM connectors on the front panel of Hydra Series II. Then jumper Hydra  
Series IIs Vterminal to the H (high) test lead of the Input Module and the COM  
terminal to the L (low) test lead.  
7. On Hydra Series II, select the VDC function, 3V range, and assign a HI alarm limit  
of +1.0000 for channels 0 through 3. Set up all other channels (4-20) to the OFF  
function. Select a scan interval of 5 seconds.  
8. Set the 5700A to output +0.9900 volts.  
9. Press Hydra Series IIs Q button. Hydra Series II should scan channels 0 through 3  
every 5 seconds.  
10. Using a digital multimeter, again verify that alarm outputs 0 through 3 are in the  
OFF or HIGH state.  
11. Set the 5700A to output +1.1000 volts. Verify that the alarm outputs 0 through 3 are  
in the ON or LOW state (measure less than +0.8V dc).  
7-19  
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2635A  
Users Manual  
ALARM OUTPUTS  
DIGITAL I/O  
ALARM  
OUTPUT  
CONNECTOR  
+ –  
9-16 V  
0
1
2
3 TR  
0
1
2
3
4
5
6
7
Σ  
+30V  
!
DC PWR  
0
1 2 3 GND  
11 12 13 14 15 16 17 18 19 20  
H L H L H L H L H L H L H L H L H L H L  
SOURCE  
(4-WIRE)  
INPUT  
MODULE  
H L H L H L H L H L H L H L H L H L H L  
SENSE  
(4-WIRE)  
1
2
3
4
5
6
7
8
9
10  
5700A  
HYDRA  
FRONT PANEL  
OUTPUT  
SENSE  
V
V A  
WIDEBAND  
HI  
HI  
REVIEW  
LAST  
LO  
LO  
COM  
V
HI  
FUNC  
ALRM  
300V  
MAX  
AUX  
CURRENT  
GUARD GROUND  
Mx+B  
(USE STACKED  
BANANA JACKS)  
op66f.eps  
Figure 7-4. Dedicated Alarms Output Test  
7-20  
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Maintenance  
Calibration  
7
External Trigger Input Test  
The External Trigger Input Test verifies that the rear panel trigger input of Hydra Series  
II is functioning properly.  
1. Switch OFF power to the instrument and disconnect all high voltage inputs.  
2. Remove the Alarm Output eight terminal connector module from the rear of Hydra  
Series II and all external connections to it. Connect short wires (to be used as test  
leads) to the GROUND and TR terminals. Leave other ends of wires unconnected at  
this time. Reinstall the connector. Refer to Figure 7-5.  
3. Switch power ON.  
4. On Hydra Series II, select the VDC function, 30V range for channels 0 through  
5.Select a scan interval of 30 seconds.  
5. Select trigger ON to enable the external trigger input. Press the K and M  
(TRIGS) buttons (the display shows TRIG), then press either the up or down arrow  
buttons to display ON. Press E.  
6. Press Hydra Series IIs Q button. Hydra Series II should scan channels 0 through 5  
once every 30 seconds.  
7. During the interval when scanning is not occurring, connect (short) the test leads of  
the TR and ground Alarm Output terminals.  
Ensure the connection causes a single scan to occur.  
8. Disconnect (open) the TR and ground connection.  
Ensure the scan continues to execute at its specified interval.  
ALARM OUTPUTS  
DIGITAL I/O  
+ –  
9-16 V  
0
1
2
3 TR  
0  
1  
2  
3  
4  
5  
6  
7  
Σ
+30V  
!
DC PWR  
op67f.eps  
Figure 7-5. External Trigger Test  
Calibration  
Note  
Refer to the Fluke Hydra Series II Service Manual (P/N 688868) for  
calibration procedures. The instrument must be stabilized in an  
environment with an ambient temperature of 22 to 24ºC and a relative  
humidity of less than 70% and must have been turned on for at least 30  
minutes prior to calibration.  
The instrument features closed-case calibration controlled over the Computer Interface.  
Using known reference sources, closed-case calibration has many advantages. There are  
7-21  
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2635A  
Users Manual  
no parts to disassemble, no mechanical adjustments to make, and the instrument can be  
calibrated by an automated instrumentation system.  
The instrument should normally be calibrated on a regular cycle, typically every 90 days  
or 1 year. The chosen calibration cycle depends on the accuracy specification you wish  
to maintain. The instrument should also be calibrated if it fails the performance test or  
has undergone repair.  
Note  
Do not press CAL ENABLE unless you have a copy of the Service Manual  
and intend to calibrate the instrument. If you have activated calibration  
and wish to exit calibration, press CAL ENABLE until CAL disappears  
from the display (or press power OFF).  
Refer to the Hydra Series II Service Manual for the essential calibration procedures.  
Variations in the Display  
Under normal operation, the display presents various combinations of brightly and dimly  
lit annunciators and digits. However, you may encounter other, random irregularities  
across different areas of the display under the following circumstances:  
After prolonged periods of displaying the same information.  
If the display has not been used for a prolonged period.  
This phenomenon can be cleared by activating the entire display and leaving it on  
overnight (or at least for several hours). Use the following procedure to keep the display  
fully lit:  
1. With power OFF, press and hold K, then press power ON.  
2. Wait a moment for the instrument to beep, then release K.The entire display will  
now stay on until you are ready to deactivate it.  
3. At the end of the activation period, press any button on the front panel; the  
instrument resumes the mode in effect prior to the power interruption (Active or  
Inactive).  
Service  
If the instrument fails, check that operating instructions presented earlier in this manual  
are being followed. If the problem cannot be remedied, forward the instrument, postage  
paid, to the nearest Fluke/Philips Service Center. Be sure to pack the instrument  
securely; use the original container if available. Include a description of the problem.  
Fluke assumes NO responsibility for damage in transit.  
To locate an authorized service center, visit us on the World Wide Web: www.fluke.com  
or call Fluke using any of the phone numbers listed below.  
1-800-44-FLUKE (1-800-443-5853) in U.S.A. and Canada  
+31 402-678-200 in Europe  
+81-3-3434-0181 Japan  
+65-*-276-6196 Singapore  
+1-425-356-5500 in other countries  
7-22  
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Appendices  
Appendix  
Title  
Page  
A
B
C
D
E
F
Specifications....................................................................................................... A-1  
Crosstalk Considerations ..................................................................................... B-1  
Binary Upload of Logged Data............................................................................ C-1  
RS-232 Cabling.................................................................................................... D-1  
8-Bit Binary-Coded-Decimal Table..................................................................... E-1  
Memory Card File Formats.................................................................................. F-1  
True RMS Measurements.................................................................................... G-1  
G
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Appendix A  
Specifications  
Introduction  
The instrument specifications presented here are applicable within the conditions listed  
in the Environmental chapter.  
The specifications state total instrument accuracy following calibration, including:  
A/D errors  
Linearization conformity  
Initial calibration errors  
Isothermality errors  
Relay thermal emfs  
Reference junction conformity  
Temperature coefficients  
Humidity errors  
Sensor inaccuracies are not included in the accuracy figures.  
Accuracies at Ambient Temperatures Other than Specified  
To determine typical accuracies at temperatures intermediate to those listed in the  
specification tables, linearly interpolate between the applicable 0ºC to 60ºC and 18ºC to  
28ºC accuracy specifications.  
Response Times  
Refer to Typical Scanning Rate and Maximum Autoranging Time later in this Appendix.  
DC Voltage Measurements  
Resolution  
See Table A-1  
A-1  
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2635A  
Users Manual  
Table A-1. DC Voltage Measurements - Resolution  
Range  
Resolution  
Slow  
Fast  
90 mV*  
300 mV  
3V  
1 µV  
10 µV  
0.1 mV  
1 mV  
10 µV  
0.1 mV  
1 mV  
30V  
10 mV  
0.1 V  
300V  
10 mV  
10 µV  
900 mV**  
0.1 mV  
*
Not used in Autoranging  
*** Computer interface only (see FUNC command).  
Accuracy  
See Table A-2.  
Table A-2. DC Voltage Measurements - Accuracy  
ACCURACY ±(%±V)  
RANGE  
18°C TO 28°C  
0°C TO 60°C  
90 DAYS  
SLOW  
1 YEAR  
SLOW  
1 YEAR  
FAST  
1 YEAR  
SLOW  
1 YEAR  
FAST  
90 mV*  
300 mV  
3V  
.019% + 6 µV  
.018% + 20 µV  
.019% + 0.2 mV  
.019% + 2 mV  
.019% + 20 mV  
.016% + 20 µV  
.024% + 6 µV  
.023% + 20 µV  
.024% + 0.2 mV  
.024% + 2 mV  
.024% + 20 mV  
.021% + 20 µV  
.044% + 20 µV  
.040% + 0.2 mV  
.041% + 2 mV  
.041% + 20 mV  
.041% + 0.2 V  
.037% + 0.3 mV  
.068% + 6 µV  
.067% + 20 µV  
.065% + 0.2 mV  
.086% + 2 mV  
.087% + 20 mV  
.064% + 20 µV  
.088% + 20 µV  
.084% + 0.2 mV  
.082% + 2 mV  
.103% + 20 mV  
.104% + 0.2 V  
.096% + 0.3 mV  
30V  
150/300V  
900 mV* **  
* Not used in Autoranging.  
** Computer interface only (see FUNC command).  
Input Impedance  
100 Me minimum in parallel with 150 pF maximum for all ranges 3V and below 10 Me  
in parallel with 100 pF maximum for the 30V and 300V ranges  
Normal Mode Rejection  
53 dB minimum at 60 Hz ±0.1%, slow rate  
47 dB minimum at 50 Hz ±0.1%, slow rate  
Common Mode Rejection  
120 dB minimum at dc, 1 ke imbalance, slow rate  
120 dB minimum at 50 or 60 Hz ±0.1%, 1 ke imbalance, slow rate  
A-2  
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Appendices  
Specifications  
A
Maximum Input  
300V dc or ac rms on any range for channels 0,1, and 11  
150V dc or ac rms for channels 2 to 10 and 12 to 20  
Voltage ratings between channels must not be exceeded.  
Cross-Talk Rejection  
Refer to Appendix B.  
A-3  
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2635A  
Users Manual  
AC Voltage Inputs (True rms AC Voltage, AC-Coupled Inputs)  
Resolution  
See Table A-3.  
Table A-3. AC Voltage Measurements - Resolution  
Range  
Resolution  
Minimum Input for Rated  
Accuracy  
Slow  
Fast  
300 mV  
3V  
30V  
10 µV  
100 µV  
1 mV  
100 µV  
1 mV  
10 mV  
100 mV  
20 mV  
200 mV  
2V  
150/300V  
10 mV  
20V  
Accuracy  
See Table A-4.  
Table A-4. AC Voltage Measurements - Accuracy  
1 Year Accuracy ±(% ± V)  
18°C to 28°C 0°C to 60°C  
Range  
Frequency  
Slow  
Fast  
Slow  
Fast  
20 Hz - 50 Hz  
1.43% + 0.25 mV 1.43% + 0.4 mV  
0.30% + 0.25 mV 0.30% + 0.4 mV  
0.16% + 0.25 mV 0.16% + 0.4 mV  
0.37% + 0.25 mV 0.37% + 0.4 mV  
1.54% + 0.25 mV  
0.41% + 0.25 mV  
0.27% + 0.25 mV  
0.68% + 0.25 mV  
3.0% + 0.30 mV  
7.0% + 0.50 mV  
1.53% + 2.5 mV  
0.40% + 2.5 mV  
0.24% + 2.5 mV  
0.35% + 2.5 mV  
0.9% + 3.0 mV  
1.4% + 5.0 mV  
1.58% + 25 mV  
0.45% + 25 mV  
0.30% + 25 mV  
0.40% + 25 mV  
1.1% + 30 mV  
2.2% + 50 mV  
1.57% + 0.25V  
0.44% + 0.25V  
0.29% + 0.25V  
0.38% + 0.25V  
1.0% + 0.30V  
1.54% + 0.4 mV  
0.41% + 0.4 mV  
0.27% + 0.4 mV  
0.68% + 0.4 mV  
3.0% + 0.5 mV  
7.0% + 1.0 mV  
1.53% + 4 mV  
0.40% + 4 mV  
0.24% + 4 mV  
0.35% + 4 mV  
0.9% + 5 mV  
50 Hz - 100 Hz  
100 Hz - 10 kHz  
10 kHz - 20 kHz  
20 kHz - 50 kHz  
50 kHz - 100 kHz  
20 Hz - 50 Hz  
300 mV  
1.9% + 0.30 mV  
5.0% + 0.50 mV  
1.42% + 2.5 mV  
0.29% + 2.5 mV  
0.13% + 2.5 mV  
0.22% + 2.5 mV  
0.6% + 3.0 mV  
1.0% + 5.0 mV  
1.43% + 25 mV  
0.29% + 25 mV  
0.15% + 25 mV  
0.22% + 25 mV  
0.9% + 30 mV  
2.0% + 50 mV  
1.42% + 0.25V  
0.29% + 0.25V  
0.14% + 0.25V  
0.22% + 0.25V  
0.9% + 0.30V  
1.9% + 0.5 mV  
5.0% + 1.0 mV  
1.42% + 4 mV  
0.29% + 4 mV  
0.13% + 4 mV  
0.22% + 4 mV  
0.6% + 5 mV  
1.0% + 10 mV  
1.43% + 40 mV  
0.29% + 40 mV  
0.15% + 40 mV  
0.22% + 40 mV  
0.9% + 50 mV  
2.0% + 100 mV  
1.42% + 0.4V  
0.29% + 0.4V  
0.14% + 0.4V  
0.22% + 0.4V  
0.9% + 0.5V  
50 Hz - 100 Hz  
100 Hz - 10 kHz  
10 kHz - 20 kHz  
20 kHz - 50 kHz  
50 kHz - 100 kHz  
20 Hz - 50 Hz  
3V  
1.4% + 10 mV  
1.58% + 40 mV  
0.45% + 40 mV  
0.30% + 40 mV  
0.40% + 40 mV  
1.1% + 50 mV  
2.2% + 100 mV  
1.57% + 0.4V  
0.44% + 0.4V  
0.29% + 0.4V  
0.38% + 0.4V  
1.0% + 0.5V  
50 Hz - 100 Hz  
100 Hz - 10 kHz  
10 kHz - 20 kHz  
20 kHz - 50 kHz  
50 kHz - 100 kHz  
20 Hz - 50 Hz  
30V  
50 Hz - 100 Hz  
100 Hz - 10 kHz  
10 kHz - 20 kHz  
20 kHz - 50 kHz  
50 kHz - 100 kHz  
300V  
2.5% + 0.50V  
2.5% + 1.0V  
2.6% + 0.50V  
2.6% + 1.0V  
A-4  
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Appendices  
Specifications  
A
Temperature Measurements (Thermocouples)  
Accuracy  
See Table A-5.  
Table A-5. Temperature Measurements - Accuracy (Thermocouples) (IPTS-68)  
Thermocouple  
Accuracy (±°C)*  
18°C to 28°C  
0°C TO 60°C  
1 Year 1 Year  
Type  
Temperature  
90 Days  
Slow  
1 Year  
Slow  
1 Year  
Fast  
(C°)  
Slow  
0.54  
0.57  
0.88  
0.64  
0.62  
1.47  
2.01  
0.73  
0.68  
0.74  
1.75  
0.56  
0.64  
0.82  
1.28  
0.83  
0.59  
0.66  
1.07  
1.37  
2.26  
1.49  
1.87  
2.48  
1.38  
1.64  
2.02  
0.87  
1.09  
1.49  
3.00  
5.00  
Fast  
1.08  
1.01  
1.37  
1.30  
1.15  
2.22  
2.95  
1.60  
1.39  
1.31  
2.53  
1.08  
1.02  
1.24  
1.81  
1.72  
1.13  
1.06  
2.71  
2.67  
3.78  
2.96  
3.34  
4.24  
3.81  
3.03  
3.49  
2.10  
2.04  
2.58  
4.66  
7.60  
-100 to -30  
-30 to 150  
0.42  
0.37  
0.44  
0.51  
0.43  
0.81  
1.05  
0.61  
0.53  
0.50  
1.00  
0.43  
0.38  
0.41  
0.67  
0.69  
0.45  
0.41  
0.89  
0.93  
1.39  
1.02  
1.23  
1.56  
1.22  
1.18  
1.42  
0.73  
0.70  
0.90  
1.74  
2.81  
0.43  
0.38  
0.48  
0.52  
0.44  
0.87  
1.15  
0.62  
0.54  
0.52  
1.08  
0.44  
0.41  
0.45  
0.73  
0.71  
0.46  
0.43  
0.91  
0.98  
1.48  
1.07  
1.29  
1.65  
1.23  
1.23  
1.48  
0.75  
0.74  
0.96  
1.86  
3.03  
0.90  
0.80  
0.93  
1.12  
0.94  
1.57  
2.03  
1.42  
1.21  
1.11  
1.82  
0.89  
0.77  
0.84  
1.22  
1.51  
0.95  
0.82  
2.53  
2.35  
2.98  
2.69  
2.75  
3.38  
3.64  
2.61  
2.95  
1.92  
1.66  
2.01  
3.48  
5.56  
J
150 to 760  
-100 to -25  
-25 to 120  
K
120 to 1000  
1000 to 1372  
-100 to -25  
-25 to 120  
N
E
120 to 410  
410 to 1300  
-100 to -25  
-25 to 350  
350 to 650  
650 to 1000  
-150 to 0  
T
R
S
B
0 to 120  
120 to 400  
250 to 400  
400 to 1000  
1000 to 1767  
250 to 1000  
1000 to 1400  
1400 to 1767  
600 to 1200  
1200 to 1550  
1550 to 1820  
0 to 150  
150 to 650  
650 to 1000  
1000 to 1800  
1800 to 2316  
C
*Sensor inaccuracies are not included  
A-5  
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2635A  
Users Manual  
Table A-6. Temperature Measurements - Accuracy (Thermocouples) (ITS-90)  
Thermocouple  
Accuracy (±°C)*  
18°C to 28°C  
0°C to 60°C  
1 Year  
Type  
(°C)  
Temperature  
(°C)  
90 Days  
Slow  
0.42  
0.37  
0.44  
0.52  
0.43  
0.61  
0.89  
0.62  
0.53  
0.47  
0.70  
0.44  
0.38  
0.39  
0.50  
0.68  
0.45  
0.36  
0.83  
0.79  
0.96  
0.88  
0.83  
1.07  
1.11  
0.74  
0.82  
0.72  
0.62  
0.70  
1.12  
1.86  
1 Year  
Slow  
0.43  
0.39  
0.48  
0.53  
0.44  
0.68  
0.98  
0.63  
0.55  
0.49  
0.78  
0.46  
0.39  
0.43  
0.56  
0.69  
0.46  
0.39  
0.85  
0.81  
1.05  
0.89  
0.89  
1.17  
1.12  
0.77  
0.89  
0.73  
0.64  
0.76  
1.25  
2.08  
1 Year  
Fast  
0.91  
0.80  
0.94  
1.13  
0.93  
1.38  
1.87  
1.44  
1.22  
1.08  
1.52  
0.91  
0.77  
0.82  
1.05  
1.50  
0.95  
0.78  
2.47  
2.30  
2.59  
2.60  
2.34  
2.96  
3.53  
2.25  
2.35  
1.90  
1.62  
1.81  
2.86  
4.61  
1 Year  
Fast  
1.08  
1.02  
1.38  
1.31  
1.16  
2.03  
2.79  
1.61  
1.39  
1.28  
2.23  
1.09  
0.98  
1.23  
1.63  
1.71  
1.13  
1.02  
2.66  
2.53  
3.42  
2.80  
2.94  
3.84  
3.69  
2.57  
2.90  
2.08  
1.94  
2.38  
4.04  
6.66  
Slow  
0.55  
0.57  
0.88  
0.65  
0.62  
1.28  
1.85  
0.75  
0.67  
0.69  
1.45  
0.57  
0.61  
0.80  
1.11  
0.82  
0.59  
0.61  
1.02  
1.15  
1.85  
1.26  
1.47  
2.03  
1.27  
1.18  
1.43  
0.86  
0.99  
1.29  
2.38  
4.06  
-100 to -30  
-30 to 150  
J
150 to 760  
-100 to -25  
-25 to 120  
K
120 to 1000  
1000 to 1372  
-100 to -25  
-25 to 120  
N
E
120 to 410  
410 to 1300  
-100 to -25  
-25 to 350  
350 to 650  
650 to 1000  
-150 to 0  
T
R
S
B
0 to 120  
120 to 400  
250 to 400  
400 to 1000  
1000 to 1767  
250 to 1000  
1000 to 1400  
1400 to 1767  
600 to 1200  
1200 to 1550  
1550 to 1820  
0 to 150  
150 to 650  
650 to 1000  
1000 to 1800  
1800 to 2316  
C
* Sensor inaccuracies are not included.  
A-6  
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Appendices  
Specifications  
A
Input Impedance  
100 Mminimum in parallel with 150 pF maximum  
Common Mode and Normal Mode Rejection  
See the specifications for dc voltage measurements.  
Cross-Talk Rejection  
Refer to Appendix B.  
Open Thermocouple Detect  
Small ac signal injection and detection scheme before each measurement detects greater  
than 1 to 4 kas open. Performed on each channel unless defeated by computer  
command  
Temperature Measurements (RTDs)  
Accuracy  
See Table A-7, A-8 and A-9.  
Table A-7. Temperature Measurements - Accuracy (RTDs) (IEC751 Amendment 2) (ITS-90)  
RTD  
Temperature  
(°C)  
4-Wire Accuracy* (±°C)  
18°C to 28°C  
Resolution  
Slow Fast  
0°C to 60°C  
90 Day  
1 Year  
Slow  
1 Year  
1 Year  
1 Year  
Fast  
Slow  
0.05  
0.08  
0.10  
0.13  
0.19  
Fast  
0.47  
0.55  
0.58  
0.65  
0.76  
Slow  
0.06  
0.13  
0.17  
0.24  
0.36  
-200.00  
0.00  
0.02  
0.02  
0.02  
0.02  
0.02  
0.1  
0.1  
0.1  
0.1  
0.1  
0.05  
0.09  
0.10  
0.14  
0.20  
0.48  
0.59  
0.64  
0.75  
0.92  
100.00  
300.00  
600.00  
* Sensor inaccuracies are not included  
Table A-8. Temperature Measurements - Accuracy (RTDs) (IEC751 Amendment 1) (ITS-90)  
RTD  
Temperature  
(°C)  
4-Wire Accuracy* (±°C)  
18°C to 28°C  
Resolution  
Slow Fast  
0°C to 60°C  
90 Day  
1 Year  
Slow  
1 Year  
1 Year  
1
Slow  
Fast  
Slow  
Year  
Fast  
-200.00  
0.00  
0.02  
0.02  
0.02  
0.02  
0.02  
0.1  
0.1  
0.1  
0.1  
0.1  
0.11  
0.09  
0.11  
0.19  
0.44  
0.11  
0.09  
0.11  
0.20  
0.45  
0.53  
0.55  
0.59  
0.70  
1.01  
0.12  
0.13  
0.18  
0.30  
0.61  
0.54  
0.59  
0.65  
0.81  
1.17  
100.00  
300.00  
600.00  
* Sensor inaccuracies are not included  
A-7  
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2635A  
Users Manual  
Table A-9. Temperature Measurements - Accuracy (RTDs) (IEC751) (IPTS-68)  
4-Wire Accuracy* (±°C)  
RTD  
Resolution  
18°C to 28°C  
0°C to 60°C  
Temperature  
(°C)  
Slow  
Fast  
90 Day  
Slow  
1 Year  
Slow  
1 Year  
Fast  
1 Year  
Slow  
1 Year  
Fast  
-200.00  
0.00  
0.02  
0.02  
0.02  
0.02  
0.02  
0.1  
0.1  
0.1  
0.1  
0.1  
0.11  
0.09  
0.12  
0.23  
0.56  
0.11  
0.09  
0.12  
0.24  
0.56  
0.53  
0.55  
0.60  
0.74  
1.13  
0.12  
0.13  
0.18  
0.34  
0.73  
0.54  
0.59  
0.66  
0.84  
1.29  
100.00  
300.00  
600.00  
* Sensor inaccuracies are not included  
RTD Type  
DIN/IEC 751, 100e Platinum (385)  
2-wire Accuracy  
For 2-wire sensors with R0 = 100: degrade accuracy by 5.0ºC per lead-ohm, plus  
degrade accuracy an additional 11ºC for channels 1 to 20 and 0.05ºC for channel 0.  
Maximum Current Through Sensor  
1 mA  
Typical Full Scale Voltage  
0.22 V  
Maximum Open Circuit Voltage  
3.2 V  
Maximum Sensor Temperature  
600ºC nominal  
Cross-Talk Rejection  
Refer to Appendix B.  
AC Voltage Measurements  
AC voltage measurements are true rms and use ac-coupled inputs.  
A-8  
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Appendices  
Specifications  
A
Resolution  
See Table A-10.  
Table A-10. AC Voltage Measurements - Resolution  
Resolution Minimum Input for Rated  
Range  
Slow  
Fast  
Accuracy  
20 mV  
200 mV  
2V  
300 mV  
3V  
10 µV  
100 µV  
1 mV  
100 µV  
1 mV  
30V  
10 mV  
100 mV  
150/300V  
10 mV  
20V  
Accuracy  
See Table A-11.  
Table A-11. AC Voltage Measurements - Accuracy  
1 Year Accuracy ±(% ± V)  
18°C to 28°C 0°C to 60°C  
Slow Fast  
Range  
Frequency  
Fast  
Slow  
20 Hz - 50 Hz  
1.43% + 0.25 mV 1.43% + 0.4 mV  
0.30% + 0.25 mV 0.30% + 0.4 mV  
0.16% + 0.25 mV 0.16% + 0.4 mV  
0.37% + 0.25 mV 0.37% + 0.4 mV  
1.54% + 0.25 mV 1.54% + 0.4 mV  
0.41% + 0.25 mV 0.41% + 0.4 mV  
0.27% + 0.25 mV 0.27% + 0.4 mV  
0.68% + 0.25 mV 0.68% + 0.4 mV  
50 Hz - 100 Hz  
100 Hz - 10 kHz  
10 kHz - 20 kHz  
20 kHz - 50 kHz  
300 mV  
1.9% + 0.30 mV  
1.9% + 0.5 mV  
5.0% + 1.0 mV  
1.42% + 4 mV  
0.29% + 4 mV  
0.13% + 4 mV  
0.22% + 4 mV  
0.6% + 5 mV  
1.0% + 10 mV  
1.43% + 40 mV  
0.29% + 40 mV  
0.15% + 40 mV  
0.22% + 40 mV  
0.9% + 50 mV  
2.0% + 100 mV  
1.42% + 0.4V  
0.29% + 0.4V  
0.14% + 0.4V  
0.22% + 0.4V  
0.9% + 0.5V  
3.0% + 0.30 mV  
7.0% + 0.50 mV  
1.53% + 2.5 mV  
0.40% + 2.5 mV  
0.24% + 2.5 mV  
0.35% + 2.5 mV  
0.9% + 3.0 mV  
1.4% + 5.0 mV  
1.58% + 25 mV  
0.45% + 25 mV  
0.30% + 25 mV  
0.40% + 25 mV  
1.1% + 30 mV  
2.2% + 50 mV  
1.57% + 0.25V  
0.44% + 0.25V  
0.29% + 0.25V  
0.38% + 0.25V  
1.0% + 0.30V  
3.0% + 0.5 mV  
7.0% + 1.0 mV  
1.53% + 4 mV  
0.40% + 4 mV  
0.24% + 4 mV  
0.35% + 4 mV  
0.9% + 5 mV  
1.4% + 10 mV  
1.58% + 40 mV  
0.45% + 40 mV  
0.30% + 40 mV  
0.40% + 40 mV  
1.1% + 50 mV  
2.2% + 100 mV  
1.57% + 0.4V  
0.44% + 0.4V  
0.29% + 0.4V  
0.38% + 0.4V  
1.0% + 0.5V  
50 kHz - 100 kHz 5.0% + 0.50 mV  
20 Hz - 50 Hz  
1.42% + 2.5 mV  
0.29% + 2.5 mV  
0.13% + 2.5 mV  
0.22% + 2.5 mV  
0.6% + 3.0 mV  
50 Hz - 100 Hz  
100 Hz - 10 kHz  
10 kHz - 20 kHz  
20 kHz - 50 kHz  
3V  
50 kHz - 100 kHz 1.0% + 5.0 mV  
20 Hz - 50 Hz  
1.43% + 25 mV  
0.29% + 25 mV  
0.15% + 25 mV  
0.22% + 25 mV  
0.9% + 30 mV  
50 Hz - 100 Hz  
100 Hz - 10 kHz  
10 kHz - 20 kHz  
20 kHz - 50 kHz  
30V  
50 kHz - 100 kHz 2.0% + 50 mV  
20 Hz - 50 Hz  
1.42% + 0.25V  
0.29% + 0.25V  
0.14% + 0.25V  
0.22% + 0.25V  
0.9% + 0.30V  
50 Hz - 100 Hz  
100 Hz - 10 kHz  
10 kHz - 20 kHz  
20 kHz - 50 kHz  
300V  
50 kHz - 100 kHz 2.5% + 0.50V  
2.5% + 1.0V  
2.6% + 0.50V  
2.6% + 1.0V  
A-9  
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2635A  
Users Manual  
Maximum Voltage Input VS. Frequency Input  
See Table A-12.  
Table A-12. AC Voltage Measurements  
Maximum Input at Upper Frequency  
300V rms  
Frequency  
20 Hz - 50 Hz  
50 Hz - 100 Hz  
100 Hz - 10kHz  
10 kHz - 20 kHz  
20 kHz - 50 kHz  
50 kHz - 100 kHz  
300V rms  
200V rms  
100V rms  
40V rms  
20V rms  
Input Impedance  
1 Min parallel with 100 pF maximum Maximum  
Maximum Crest Factor  
3.0  
2.0 for rated accuracy  
Crest Factor Error  
Non-sinusoidal input signals with crest factors between 2 and 3 and pulse widths 100 µs  
and longer add 0.2% to the accuracy specifications.  
Common Mode Rejection  
80 dB minimum at 50 or 60 Hz ± 0.1%, 1 kimbalance, slow rate  
Maximum AC Input  
300V rms or 424V peak on channels 0, 1, and 11  
150V rms or 212V peak on channels 2 to 10 and 12 to 20  
Voltage ratings between channels must not be exceeded  
2 x 106 Volt-Hertz product on any range, normal mode input  
1 x 10 6 Volt-Hertz product on any range, common mode input  
DC Component Error  
SCAN and first MONitor measurements will be incorrect if the dc signal component  
exceeds 60 counts in slow rate or 10 counts in fast rate. To measure ac with a dc  
component present, MONitor the input and wait 5 seconds before recording the  
measurement.  
Cross-Talk Rejection  
Refer to Appendix B.  
A-10  
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Appendices  
Specifications  
A
Resistance Measurements  
Resolution  
See Table A-13.  
Table A-13. Resistance Measurements - Resolution.  
Range  
Resolution  
Typical Full  
Scale Voltage  
Maximum  
Current  
Through  
Unknown  
Maximum  
Open Circuit  
Voltage  
Slow  
Fast  
300Ω  
3 kΩ  
10 mΩ  
0.1Ω  
1Ω  
0.1Ω  
1Ω  
0.22V  
0.25V  
0.29V  
0.68V  
2.25V  
2.72V  
1 mA  
110 µA  
13 µA  
3.2 µA  
3.2 µA  
3.2 µA  
3.2V  
1.5V  
1.5V  
3.2V  
3.2V  
3.2V  
30 kΩ  
300 kΩ  
3 MΩ  
10 Ω  
100 Ω  
1 kΩ  
10 kΩ  
10 Ω  
100 Ω  
1 kΩ  
10 MΩ  
Accuracy  
See Table A-14.  
Table A-14. Resistance Measurements - Accuracy (Four-Wire)  
4-Wire Accuracy ±(%±)  
18°C to 28°C  
1 Year, Slow  
Range  
0°C to 60°C  
90 Days, Slow  
1 Year, Fast  
1 Year, Slow  
1 Year, Fast  
300Ω  
3 kΩ  
0.013% + 20 mΩ  
0.015% + 0.2Ω  
0.013% + 2Ω  
0.014% + 20 mΩ  
0.016% + 0.2Ω  
0.014% + 2Ω  
0.014% + 0.2Ω  
0.016% + 2Ω  
0.031% + 20 mΩ  
0.039% + 0.2Ω  
0.039% + 2Ω  
0.031% + 0.2Ω  
0.039% + 2Ω  
30 kΩ  
300 kΩ  
3 MΩ  
10 MΩ  
0.014% + 20Ω  
0.021% + 200Ω  
0.063% + 2 kΩ  
0.039% + 20Ω  
0.050% + 200Ω  
0.231% + 2 kΩ  
0.923% + 20 kΩ  
0.020% + 20Ω  
0.059% + 200Ω  
0.168% + 2 kΩ  
0.021% + 20Ω  
0.063% + 200Ω  
0.169% + 2 kΩ  
0.050% + 20Ω  
0.231% + 200Ω  
0.709% + 20 k0.573% + 2 kΩ  
A-11  
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2635A  
Users Manual  
2-Wire Accuracy  
Add 4.0to accuracy specifications for channels 1 to 20, and add 20 mfor channel 0.  
Lead wire resistances are not included.  
300V dc or ac rms on all ranges  
Cross-Talk Rejection  
Refer to Appendix B.  
Frequency Measurements  
Resolution and Accuracy  
See Table A-15.  
Table A-15. Frequency Measurements-Resolution and Accuracy  
Resolution Accuracy + (% ± Hz)  
Range  
Slow  
Fast  
Slow  
Fast  
15 Hz - 900 Hz  
9 kHz  
0.01 Hz  
0.1 Hz  
1 Hz  
0.1 Hz  
1 Hz  
0.05% + 0.02 Hz  
0.05% + 0.1 Hz  
0.05% + 1 Hz  
0.05% + 0.2 Hz  
0.05% + 1 Hz  
90 kHz  
10 Hz  
100 Hz  
1 kHz  
0.05% + 10 Hz  
0.05% + 100 Hz  
0.05% + 1 kHz  
900 kHz  
1 MHz  
10 Hz  
100 Hz  
0.05% + 10 Hz  
0.05% + 100 Hz  
Frequency Range  
15 Hz to greater than 1 MHz  
Input Sensitivity  
See Table A-16.  
Table A-16. Frequency Measurements - Input Sensitivity  
Frequency Level (sine wave)  
15 Hz - 100 kHz  
100 mV rms  
150 mV rms  
2V rms  
100 kHz - 300 kHz  
300 kHz - 1 MHz -  
Above 1 MHz  
Not specified  
A-12  
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Appendices  
Specifications  
A
Maximum AC Input  
300V rms or 424V peak on channels 0, 1, and 11  
150V rms or 212V peak on channels 2 to 10 and 12 to 20  
Voltage ratings between channels must not be exceeded  
2 x 106 Volt-Hertz product on any range, normal mode input  
1 x 106 Volt-Hertz product on any range, common mode input  
Cross-Talk Rejection  
Refer to Appendix B.  
Typical Scanning Rate  
See table below. The measurement conditions are: averaged rate over 20 scans;  
continuous scanning; alarm limits and Mx+B scanning set on all channels; logging data  
to internal memory; and RS-232 communications set at 9600 baud. Measurements were  
taken with short-circuit inputs on all channels, except frequency, which was taken with  
5V at 15 Hz on all channels.  
Table A-17. Typical Scanning Rate  
CHANNELS  
FUNCTION  
RANGE  
SLOW  
10  
FAST  
10  
1
20  
1
20  
VDC  
300 mV  
3V  
1.8  
1.8  
1.8  
1.8  
1.7  
1.0  
1.7  
1.1  
1.1  
1.1  
1.1  
1.1  
1.7  
1.7  
1.7  
1.2  
1.2  
1.1  
1.7  
0.5  
3.9  
3.9  
3.9  
3.9  
3.6  
3.3  
3.1  
1.5  
1.5  
1.5  
1.5  
1.5  
3.1  
3.1  
3.1  
1.8  
1.6  
1.6  
3.1  
0.6  
4.1  
4.1  
4.1  
4.1  
3.9  
3.8  
3.2  
1.6  
1.6  
1.6  
1.6  
1.5  
3.2  
3.2  
3.2  
1.8  
1.7  
1.6  
3.2  
0.6  
2.5  
2.5  
2.5  
2.5  
2.4  
2.1  
2.1  
1.3  
1.3  
1.3  
1.3  
1.3  
2.1  
2.1  
2.1  
1.7  
1.7  
1.7  
2.1  
0.6  
13.7  
13.7  
13.7  
13.6  
11.3  
12.2  
6.0  
18.4  
18.4  
18.3  
18.2  
14.1  
16.6  
6.7  
30V  
150/300V  
AUTO  
J (TC)  
PT (RTD)  
300 mV  
3V  
TEMPERATURE  
VAC  
2.5  
2.6  
2.5  
2.6  
30V  
2.5  
2.6  
150/300V  
AUTO  
300Ω  
2.5  
2.6  
2.4  
2.5  
OHMS  
6.0  
6.7  
3 kΩ  
6.0  
6.7  
30 kΩ  
300 kΩ  
3 MΩ  
6.0  
6.7  
4.0  
4.4  
3.9  
4.2  
10 MΩ  
AUTO  
ANY  
3.8  
4.0  
6.0  
6.7  
FREQUENCY  
0.7  
0.7  
A-13  
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2635A  
Users Manual  
Maximum Autoranging Time  
See Table A-18 (shown in seconds per channel).  
Totalizing Input  
Input Voltage  
30V maximum  
4V minimum  
2V peak minimum signal  
Isolation  
None  
dc-coupled  
Table A-18. Autoranging Rates  
Function  
Range Change  
Slow  
Fast  
VDC  
300 mV  
150V  
---------------------------->  
---------------------------->  
---------------------------->  
---------------------------->  
---------------------------->  
---------------------------->  
150 V  
300 mV  
150V  
0.25  
0.25  
1.40  
1.40  
1.70  
1.50  
0.19  
0.18  
1.10  
1.10  
0.75  
0.60  
VAC  
300 mV  
150 mV  
300 Ω  
300 mV  
10.0 MΩ  
300 Ω  
Ohms  
10.0 MΩ  
Threshold  
1.4V  
Hysteresis  
500 mV  
Input Debouncing  
None or 1.75 ms  
Rate  
0 to 5 kHz with debouncing off  
Maximum Count  
65,535  
Digital Inputs  
The specifications for the digital inputs are provided in the following paragraphs.  
A-14  
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Appendices  
Specifications  
A
Input Voltage  
30V maximum  
-4V minimum  
Isolation  
none  
dc-coupled  
Threshold  
1.4V  
Hysteresis  
500 mV  
Trigger Inputs  
Input Voltages  
contact closure and TTL compatible  
“high” =2.0V min, 7.0V max  
“low” = -0.6V min, 0.8V max  
Isolation  
None  
dc-coupled  
Minimum Pulse Width  
5 µs  
Maximum Frequency  
5 Hz  
Specified Conditions  
The instrument must be in the quiescent state, with no interval scans in process, no  
commands in the queue, no RS-232 activity, and no front panel activity if the latency and  
repeatability performance is to be achieved.  
Maximum Latency  
Latency is measured from the edge of the trigger input to the start of the first channel  
measurement for the Specified Conditions (above).  
540 ms for fast rate, scanning DCV, ACV, ohms, and frequency only  
610 ms for fast rate, scanning any thermocouple or 100 mV dc channels  
500 ms for slow rate, scanning DCV, ACV, ohms, and frequency only  
950 ms for slow rate, scanning any thermocouple or 100 mV dc channels  
Repeatability  
3 ms for the Specified Conditions (above)  
A-15  
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2635A  
Users Manual  
Digital and Alarm Outputs  
The specifications for the digital and alarm outputs are provided in the following  
paragraphs.  
Output Logic Levels  
Logical “zero”:  
Logical “one”:  
0.8V max for an Iout of -1.0 mA (1LSTTL load)  
3.8V min for an Iout of 0.05 mA (1LSTTL load)  
For non-TTL loads: 1.8V max for an Iout or -20 mA  
Logical “zero”: 3.25 max for an Iout of -50 mA  
Isolation  
none  
Real-Time Clock and Calendar  
The specifications for the real-time clock and calendar are provided in the following  
paragraphs.  
Accuracy  
Within 1 minute per month for 0°C to 50°C range  
Battery Life  
>10 unpowered instrument years for 0°C to 28°C  
>3 unpowered instrument years for 0°C to 50°C  
>2 unpowered instrument years for 50°C to 70°C  
Environmental Specifications  
The environmental specifications are provided in the following paragraphs.  
Warmup Time  
1 hour to rated specifications  
15 minutes when relative humidity is kept below the rated maximum minus 20% (e.g.  
below 70% for a 90% maximum rating).  
Operating Temperature  
0°C to 60°C  
Storage Temperature  
-40°C to +75°C  
Instrument storage at temperature extremes may necessitate adding up to 0.008% to the  
dc and ac voltage accuracy specifications. Alternatively, any resulting shift can be  
compensated for by recalibrating the instrument.  
A-16  
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Appendices  
Specifications  
A
Relative Humidity (Non-Condensing)  
90% maximum for 0°C to 28°C  
75% maximum for 28°C to 35°C  
50% maximum for 35°C to 50°C  
35% maximum for 50°C to 60°C  
(Except 70% maximum for 0°C to 35°C, 0% maximum for 40°C to 50°C, and 20%  
maximum for 50°C to 60°C for the 300 ke, 3 Me, and 10 Me ranges.)  
Altitude  
Operating: 2,000 m maximum  
Non-operating: 12,200m maximum  
Vibration  
0.7g at 15 Hz  
1.3g at 25 Hz  
3g at 55 Hz  
Shock  
30g half sine per Mil-T-28800  
Bench handling per Mil-T-28800  
General  
The general specifications are provided in the following paragraphs.  
Channel Capacity  
21 Analog Inputs  
4 Alarm Outputs  
8 Digital I/O (inputs/outputs)  
Measurement Speed  
Slow rate: 4 readings/second nominal  
Fast rate: 17 readings/second nominal  
1.5 readings/second nominal for ACV and high-e inputs  
For additional information, refer to Typical Scanning Rated and Maximum Autoranging  
Time.  
Nonvolatile Memory Life  
>10 unpowered instrument years for 0°C to 28°C  
>3 unpowered instrument years for 0°C to 50°C  
>2 unpowered instrument years for 50°C to 70°C  
Stores: Real-time clock, set-up configuration, and measurement data.  
Common Mode Voltage  
300V dc or ac rms maximum from any analog input (channel) to earth provided that  
channel to channel maximum voltage ratings are observed.  
A-17  
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2635A  
Users Manual  
Voltage Ratings  
Channels 0,1, and 11 are rated at 300V dc or ac rms maximum from a channel terminal  
to earth and from a channel terminal to any other channel terminal.  
Channels 2 to 10 and 12 to 20 are rated at 150V dc or ac rms maximum from a channel  
terminal to any other channel terminal within channels 2 to 10 and 12 to 20.  
IEC Overvoltage Category II.  
Size  
9.3 cm high, 21.6 cm wide, 31.2 cm deep  
Weight  
Net, 2.95 kg  
Shipping, 4.0 kg  
Power  
90V to 264V ac (no switching required), 50 and 60 Hz, 10 VA maximum  
9V dc to 16V dc, 10W maximum  
If both sources are applied simultaneously, ac is used if it exceeds approximately 8.3  
times dc.  
Automatic switchover occurs between ac and dc without interruption.  
(At 120V ac the equivalent dc voltage is ~14.5V).  
Standards  
IEC 1010-1, ANSI/ISA S82.01-1994, CSA-C22.2 No.1010.1-92, and EN61010-1:1993.  
Complies with EN 50081-1, EN 50082-1, Vfg. 243/1991 and FCC-15B at the Class B  
level, when shielded cables are used.  
RS-232-C  
Connector:  
Signals:  
9 pin male (DB-9P)  
TX, RX, DTR, DSR, RTS, CTS, GND  
Modem Control: full duplex  
Baud rates:  
300, 600, 1200, 2400, 4800, 9600, 19200, 38400  
Data format:  
8 data bits, no parity bit, one stop bit, or 7 data bits, one parity bit  
(odd or even), one stop bit  
Flow control:  
Echo:  
CTS (Hardware) and XON/XOFF (Software)  
on/off  
A-18  
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Appendix B  
Crosstalk Considerations  
Introduction  
This appendix augments the discussion of ac signal effects on other channels (crosstalk).  
Effects on each measurement function are discussed below. These numbers should only  
be considered as references. Since cross talk can be introduced into a measurement  
system in many places, each setup must be considered individually.  
The effect of cross talk could be much better than shown for "Typical"; in extreme cases,  
the effect could be worse than the "Worst Case" numbers. In general, the "Worst Case"  
information assumes that none of the guidelines for minimizing cross talk (Chapter 1)  
have been followed; the "Typical" information assumes that the guidelines have been  
followed where reasonable.  
These numbers assume that input L (low) is tied to earth ground; refer to "Using  
Shielded Wiring" in Chapter 1. For dc volts and thermocouple temperature  
measurements, a source impedance of 1 ke in series with the H (high) input is assumed  
(except where otherwise noted.)  
AC Signal Cross Talk in a DC Voltage Channel  
VDC(error)  
DCV Error Ratio (CTRR) =  
VACrms  
Worst case  
Typical  
50, 60 Hz, ±0.1%:  
Other Frequencies:  
1.1 × 10-7  
3.8 × 10-6  
2.0 × 10-8  
8.6 × 10-7  
For example, the typical effect on a channel measuring dc volts (300 mV range) by a 300  
V ac signal at 60 Hz on another channel would be: 300 × 2.0 × 10-8 = 0.01 mV.  
B-1  
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2635A  
Users Manual  
AC Signal Cross Talk into an AC Voltage Channel  
VACrms(error)  
ACV Error Ratio =  
VACrms(crosstalk) × Frequency(crosstalk)  
Range  
Ratio (worst case)  
Ratio (typical)  
v
v
300.00 m  
4.8 × 10-8  
1.4 × 10-8  
3.0 × 10-8  
2.6 × 10-7  
3.4 × 10-6  
v × Hz  
v × Hz  
v
v
3.0000 V  
1.1 × 10-7  
v × Hz  
v × Hz  
v
v
30.000 V  
1.2 × 10-6  
v × Hz  
v × Hz  
v
v
150.00/300.00  
1.2 × 10-5  
v × Hz  
v × Hz  
For example, the typical effect on a channel measuring ac volts (300 mV range) by a  
220V ac signal at 60 Hz on another channel would be: 220 X 60 X 1.4 X 10-8 = 0.18 mV.  
AC Signal Cross Talk into an Ohms Channel  
AC Frequency = 50, 60 Hz, ±0.1%  
Ohms(error)  
OHMS Error Ratio1 =  
VACrms(crosstalk)  
Range  
Ratio (worst case)  
Ratio (typical)  
Ohms  
300.00 e 3.3 × 10-5  
3.0000 ke  
NoEffect  
Vrms  
kOhms  
Vrms  
kOhms  
2.4 × 10-6  
3.1 × 10-4  
5.6 × 10-3  
3.8 × 10-4  
6.7 × 10-7  
8.4 × 10-5  
3.7 × 10-3  
3.8 × 10-5  
Vrms  
kOhms  
Vrms  
kOhms  
Vrms  
30.000ke  
kOhms  
Vrms  
kOhms  
Vrms  
300.00 ke  
MOhms  
Vrms  
MOhms  
Vrms  
3.0000 Me  
B-2  
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Appendices  
Crosstalk Considerations  
B
MOhms  
Vrms  
MOhms  
10.000 Me  
1.4 × 10-3  
4.3 × 10-4  
Vrms  
For example, to find the typical effect of a 60 Hz, 100V ac signal on another channel for  
the 30 krange, you would calculate: 100 X 8.4 X 10-5 = 0.008 k.  
1These values assume no more than 1000 pf of capacitance between either end of the resistor (HI and LOW ) and  
earth ground.  
AC Signal Cross Talk into a Frequency Channel  
Frequency measurements are unaffected by cross talk as long as the voltage-frequency  
product is kept below the following limits:  
Worst Case  
Typical  
V x Hz Product Limit  
3.7 × 104 (V × Hz)  
1.0 × 106 (V × Hz)  
AC Signal Crosstalk into a Temperature Channel  
Frequency = 50, 60 Hz  
°C(error)  
TEMPERATURE Error Ratio =  
VACrms(crosstalk)  
Worst case  
Typical  
°C  
Vrms  
°C  
Vrms  
Types J, K, E, T, N:  
Types R, S, B, C:  
Type PT (RTD):  
2.7 × 10-3  
5.0 × 10-4  
°C  
Vrms  
°C  
Vrms  
1.1 × 10-2  
8.6 × 10-5  
2.0 × 10-3  
°C  
Vrms  
No Effect  
B-3  
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2635A  
Users Manual  
B-4  
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Appendix C  
Binary Upload of Logged Data  
Introduction  
The LOG_BIN? <index> query can be used to quickly upload logged data from a 2635A.  
The response is a single ASCII string, which encodes the raw binary data stored at the  
specified <index> position. The logged data is also retained in the 2635A.  
The measurement data returned from the 2635A is in the (binary) IEEE single-precision  
floating point format. Making use of this data can be difficult and is very machine  
dependent. A working example, using the C programming language on an IBM PC, is  
provided in this appendix. This example uses a pre-computed LOG_BIN?response  
string, and checks that the conversion process works as expected.  
Two steps are required in adapting the LOG_BIN? response string for use with your  
computer.  
First, you must decode the ASCII string into binary data.  
For example, one possible LOG_BIN? response string is:  
LOG_BIN? 1  
42@Y40BA00oo000007o0001oP000?h000  
=>  
This ASCII string represents the following binary (hex) data:  
10 24 29 10 04 91 00 0f ff  
00 00 00 00 7f c0 00 00 7f  
80 00 00 3f 80 00 00 00 00  
Second, you must convert this binary data into valid floating point numbers for your  
underlying computer architecture.  
Decoding the ASCII String  
The ASCII response string contains six bits of raw data for each ASCII character, offset  
from ASCII 0(0x30 hex, 48 decimal). Therefore, the conversion process subtracts 48  
from the integer value of each character, then shifts it into place. Each set of four ASCII  
characters form three bytes of raw data. The number of bytes of raw data depends on the  
C-1  
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2635A  
Users Manual  
number of channels for the scan. The following C code converts a LOG_BIN? response  
string into a byte array:  
/*  
-* decode(): Decode LOG_BIN? response string into raw byte stream  
**  
** Decoding is done on multiples of four input bytes:  
**  
**  
543210  
543210  
543210  
543210  
(bit number in ASCII bytes)  
**  
+--------+--------+--------+--------+  
| src[0] | src[1] | src[2] | src[3] |  
+--------+--------+--------+--------+  
**  
ASCII string input  
**  
**  
765432  
/
107654  
321076  
543210  
(bit number in raw bytes)  
**  
/
/
/
**  
/
/
**  
|
|
|
|
|
/
/
/
**  
/
**  
|
|
|
/
**  
/
**  
|
**  
76543210 76543210 76543210  
+--------+--------+--------+  
| dst[0] | dst[1] | dst[2] |  
+--------+--------+--------+  
(bit number in raw bytes)  
Raw data output  
**  
**  
**  
**  
** Inputs:  
**  
**  
**  
**  
**  
**  
**  
dst  
Destination for binary data (must have enough space  
allocated; the maximum needed is 6 timestamp bytes + 3  
bytes for temp units, measurement rate, and digital I/O  
+ 4 bytes/float * 22 floating point values = 97 bytes).  
src  
Source ASCII string (null terminated)  
** Outputs:  
**  
**  
dst  
Set to binary data, based on ASCII string  
** Returns:  
**  
*/  
Number of bytes placed in destination buffer  
int  
decode(dst, src)  
unsigned char *dst;  
char *src;  
{
/* src to dst xlate */  
static struct nibtab_s {  
int lindex;  
int lmask;  
int lshift;  
int rindex;  
int rmask;  
int rshift;  
} nibtab[3] = {  
/* left  
right */  
C-2  
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Binary Upload of Logged Data  
Appendices C  
0, 0x3f, 2,  
1, 0x0f, 4,  
2, 0x03, 6,  
1, 0x30, 4,  
2, 0x3c, 2,  
3, 0x3f, 0,  
/* dst[0] from src[0] and src[1] */  
/* dst[1] from src[1] and src[2] */  
/* dst[2] from src[2] and src[3] */  
};  
auto unsigned char n;  
auto struct nibtab_s *t;  
auto unsigned char tmpsrc[4];  
auto int dst_bytes;  
/* Number of bytes created */  
dst_bytes = 0;  
/* Process src in chunks of four */  
while (*src) {  
/* Copy source, filing "holes" at end with zeros */  
for (n = 0; n < 4; n++) {  
if (*src)  
tmpsrc[n] = *src++ - ’0’;  
else  
tmpsrc[n] = 0;  
}
/* Mung source into destination */  
for (t = nibtab; t < &nibtab[3]; t++) {  
*dst = (tmpsrc[t->lindex] & t->lmask) << t->lshift;  
*dst |= (tmpsrc[t->rindex] & t->rmask) >> t->rshift;  
dst++;  
dst_bytes++;  
}
}
return (dst_bytes);  
Figure C-1. ASCII String Decoding  
}
The raw data output array contains the information listed below. Note that the number of  
floating point values is equal to the number of channels in use, plus one. (The totalizer  
count is always present in the data, and is stored as a floating point number.)  
Time stamp (BCD format)  
byte0: hours  
byte1: minutes  
byte2: seconds  
byte3: month  
byte4: date  
byte5: year  
Temperature units, measurement rate, and I/O  
C-3  
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2635A  
Users Manual  
byte6: temperature units and rate (0x10 bit means degrees Fahrenheit, else  
Centigrade; 0x01 bit means fast rate, else slow rate)  
byte7: Alarm outputs  
byte8: Digital I/O  
Totalizer value as 32-bit single-precision IEEE floating point number stored using  
the byte ordering shown below. The format of this number is explained under  
"Floating Point Conversion".  
byte 9: MMSB of float  
byte 10: MLSB of float  
byte 11: LMSB of float  
byte 12: LLSB of float  
Measurement data; only defined channels are included (exactly like LOG?query);  
same floating point format, but with a wider range of values. NaN (Not a Number)  
is used to indicate open thermocouple, and plus or minus Inf (infinity) to indicate  
overload. The bit values for NaN and Inf are explained in the next section.  
byte 13: MMSB of float  
byte 14: MLSB of float  
byte 15: LMSB of float  
byte 16: LLSB of float  
bytes 17-20: Second measurement result, if any  
bytes 21-24: Third measurement result, if any  
...  
Since the ASCII decoding (explained above) creates data multiples of three in length, it  
is possible that there will be one or two unused bytes at the end of the decoded byte  
stream.  
Floating Point Conversion  
ANSI/IEEE Std 754-1985, "IEEE Standard for Binary Floating-Point Arithmetic,"  
describes the single-precision floating point format used to return measurement data.  
This standard defines the format for single-precision floating point as:  
X = (-1) s 2 (e-127) (1.m )  
where  
s = sign  
e = exponent  
m = mantissa  
The floating point format used is 32-bit with a 1-bit sign, 8-bit exponent, and 24-bit  
mantissa with the most significant bit hidden under the LSB of the exponent. The  
number is formatted as shown in Table C-1.  
For all other measurement queries, Hydra Series II returns the string "+9E+9" for open  
thermocouple (OTC) measurement values. However, for the LOG_BIN?query, NaN (not  
a number) is returned instead. The IEEE floating point standard defines NaN as a  
positive, maximum exponent number with non-zero mantissa bits. Hydra Series II sets  
C-4  
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Binary Upload of Logged Data  
Appendices C  
just the most significant mantissa bit, so the raw binary byte stream value is 7f c0 00 00  
(hex).  
For all other measurement queries, Hydra Series II usually returns ±1e9 for overload  
(OL) measurement values. However, for the LOG_BIN? query, Hydra Series II returns  
Inf (infinity) instead. The IEEE floating point standard defines Inf as a positive or  
negative maximum exponent number with a zero mantissa. Hydra Series II returns +Inf  
as the byte stream 7f 80 00 00 (hex) and -Inf as ff 80 00 00 (hex).  
Table C-1. Floating-Point Format  
Sign  
1 bit  
Exponent  
8 bits  
Manitssa  
23 bits (plus one hidden bit)  
high byte  
(MMSB)  
High-mid byte  
(MLSB)  
low-mid bute  
(LMSB)  
low byte  
(LLSB)  
The C code in Figure C-2 converts raw data into a useful format for the Intel x86 (IBM  
PC) architecture. The BCD time stamp is converted to integers, and floating point  
numbers created for the totalizer and measurement values.  
C-5  
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2635A  
Users Manual  
/* Import globals from main program */  
extern int timestamp[];  
extern int misc[];  
extern float values[];  
/*  
-* convert(): Convert a LOG_BIN? array of binary data into useful data  
**  
** Converts BCD values to integer, raw floating point values into float  
** values usable under the Intel x86 (IBM PC) architecture.  
**  
** Inputs:  
**  
**  
**  
src  
length  
Array of binary data, from LOG_BIN? query  
Number of bytes in src array  
** Outputs:  
**  
**  
**  
**  
*/  
timestamp[]  
Set to decimal timestamp values  
misc[]  
Set to temp units, rate, and digital I/O values  
Set to floating point values found in binary data  
(must be room for a maximum of 22 floats)  
values[]  
void  
convert(src, length)  
unsigned char *src;  
int length;  
{
unsigned char *m;  
int n;  
/* Convert timestamp from BCD to decimal */  
for (n=0; n < 6; n++, src++) {  
/* Binary Coded Decimal (BCD) format, packs the upper nibble as the  
*/  
*/  
*/  
/* tens digit, the lower nibble as the ones digit. Convert this  
/* into an integer number.  
timestamp[n] = (10 * (*src >> 4) + (*src & 0x0f));  
}
/* Save temperature units, measurement rate, and digital I/O values */  
for (n=0; n < 3; n++) {  
misc[n] = *src++;  
}
/* Convert raw measurement data into floating point */  
m = (unsigned char *)values;  
for (length -= 9; length > 3; length -= 4) {  
#ifdef sun  
/* SunOS architecture (also works for Motorola CPUs) */  
*m++ = src[0];  
*m++ = src[1];  
*m++ = src[2];  
*m++ = src[3];  
#else  
/* Assume Intel x86 architecture */  
*m++ = src[3];  
*m++ = src[2];  
*m++ = src[1];  
*m++ = src[0];  
#endif  
src += 4;  
}
}
Figure C-2. Floating_Point Conversion  
C-6  
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Binary Upload of Logged Data  
Appendices C  
Example  
Figure C-3 is a short example that uses the routines in Figures C-1 and C-2 to decode a  
fixed (pre-computed) LOG_BIN? response string.  
When compiled and run on an Intel architecture computer, the program should print  
"Conversion worked".  
Although this example is useful for educational purposes, it is not very efficient. If  
desired, the decoding and conversion processes can be combined into a single, fast  
algorithm.  
C-7  
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2635A  
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/* Globals convert() uses for destination */  
int timestamp[6];  
int misc[3];  
float values[22];  
/* Scan timestamp */  
/* Temperature units, measurement rate, digital I/O */  
/* Measurement values */  
extern int isnan();  
extern int isinf();  
/* Floating point value is NaN (not a number) */  
/* Floating point value is Inf (infinity) */  
/*  
-* main(): LOG_BIN? query response example program  
**  
** Converts a hard-coded LOG_BIN? response string into usable data.  
*/  
main()  
{
extern int decode();  
/* ASCII to binary decoding */  
/* Convert Hydra binary to usable types */  
extern void convert();  
/* Canned response for three channels: channel 1 is OTC, channel 5 is */  
/* OL and channel 10 is 1.0; remaining encoded data described below  
/* (note that you can not determine the channel number, measurement  
*/  
*/  
/* units, or measurement range, from this string; you must keep track */  
/* of that elsewhere)  
char *log_bin_response = "42@Y40BA00oo000007o0001oP000?h000";  
*/  
/* Place to temporarily store raw data; 100 bytes is more than enough */  
/* for any LOG_BIN? response string  
unsigned char raw_data[100];  
*/  
/* Decode string into raw data, then convert raw data into usable data */  
convert(raw_data, decode(raw_data, log_bin_response));  
/* Above global variables now usable; check example LOG_BIN? data */  
/* against expected values  
*/  
if ((timestamp[0] == 10) &&  
(timestamp[1] == 24) &&  
(timestamp[2] == 29) &&  
(timestamp[3] == 10) &&  
(timestamp[4] == 4) &&  
(timestamp[5] == 91) &&  
/* Hours  
/* Minutes  
/* Seconds  
/* Month  
/* Day  
*/  
*/  
*/  
*/  
*/  
*/  
/* Year  
(misc[0]  
(misc[1]  
(misc[2]  
(values[0]  
== 0) &&  
/* Temp units and rate */  
== 15) &&  
== 255) &&  
== 0.0) &&  
/* Alarm outputs  
/* Digital I/O  
*/  
*/  
*/  
*/  
*/  
*/  
/* Totalizer  
isnan(values[1]) &&  
isinf(values[2]) &&  
/* Channel 1 data  
/* Channel 5 data  
/* Channel 10 data  
(values[3]  
== 1.0)) {  
printf("Conversion worked\n");  
}
else {  
printf("ERROR: conversion did not succeed!\n");  
}
exit(0);  
}
/* If your math library supplies alternatives to isnan() or isinf(), */  
/* use them instead!  
*/  
int  
isnan(f)  
float f;  
{
/* This is not portable, or completely accurate (since NaN mantissa  
*/  
/* must only be non-zero, and the sign bit can be set), but this works */  
/* for NaN values returned by Hydra  
*/  
/* Compiler was free to promote to double */  
float ff = f;  
return ((*(unsigned long *)&ff) == 0x7fc00000L);  
}
int  
isinf(f)  
float f;  
{
/* Again, this is not portable, but this time it is accurate */  
/* Compiler was free to promote to double */  
float ff = f;  
return ((*(unsigned long *)&ff) == 0x7f800000L) ||  
((*(unsigned long *)&ff) == 0xff800000L);  
}
Figure C-3. Example  
C-8  
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Appendix D  
RS-232 Cabling  
Introduction  
This appendix details the RS-232 cabling between the instrument and a PC, instrument  
controller (Fluke 17XXA series), printer, or modem. All connections can be made using  
the Fluke RS-series of cables (see Options and Accessories in Chapter 1). RS-232 cables  
should not exceed 50 feet (15 meters) although longer cables are permitted if the load  
capacitance measured at a connection point (including signal terminator) does not  
exceed 2500 picofarads. The Fluke RS cables are 6 feet (1.83 meters) in length.  
Connections  
Figure D-1 summarizes the cable requirements for all typical RS-232 connections;  
Figure D-2 through E-6 summarize instrument cabling diagrams; Figure D-7 shows the  
pin arrangement for DB-9 and DB-25 connectors. There are two wiring schemes  
(modem and null-modem), two types of connectors (DB-9 and DB-25), two cable end  
conditions (male and female), and two equipment configurations (Data Terminal  
Equipment [DTE] and Data Communications Equipment [DCE]). Because of variations  
in RS-232 connectors, it is not possible to identify all possible configurations. In this  
application, “null-modem” refers to a reversing of the following lines; receive (RX) and  
transmit (TX), data terminal ready (DTR) and data set ready (DSR), and request to send  
(RTS) and clear to send (CTS). Not all interfaces use all lines. Check the documentation  
for the equipment you are interfacing with the instrument.  
Cables  
The Fluke RS-series of RS-232 cables are in the following standard configurations:  
RS40 - Null modem with DB-9/female and DB-25/female connectors  
RS41 - Modem with DB-9/female and DB-25/male connectors  
RS42 - Null modem with DB-9/female and DB-25/male connectors  
Cables from other sources may be used, or cables can be fabricated based on the figures  
in this appendix. The RS40 and RS42 cables are identical, except for the DB-25  
connectors (female and male, respectively). Some interfaces allow a selection of cables.  
D-1  
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2635A  
Users Manual  
For example, connection to a serial-to-parallel converter (when using a printer with a  
parallel input) may be as a DTE (cable RS42) or DCE (cable RS40).  
GENERIC  
(NULL MODEM)  
PC  
(DTE)  
HYDRA  
(DTE)  
RS43  
(DB-9/MALE)  
(DB-9/MALE)  
PC  
(DTE)  
HYDRA  
(DTE)  
RS40  
(DB-25/MALE)  
(DB-9/MALE)  
MODEM  
(DCE)  
(DB-25/FEMALE)  
HYDRA  
(DTE)  
(DB-9/MALE)  
RS41  
(MODEM)  
PRINTER  
(DTE)  
(DB-25/FEMALE)  
HYDRA  
(DTE)  
(DB-9/MALE)  
RS42  
RS42  
SERIAL-TO-PARALLEL  
(DTE)  
HYDRA  
(DTE)  
PRINTER  
PRINTER  
(DB-25/FEMALE)  
(DB-9/MALE)  
SERIAL-TO-PARALLEL  
(DCE)  
(DB-25/FEMALE)  
HYDRA  
(DTE)  
(DB-9/MALE)  
RS41  
(MODEM)  
KEY  
DTE – DATA TERMINAL EQUIPMENT  
DCE – DATA COMMUNICATIONS EQUIPMENT  
MALE  
FEMALE  
op71f.eps  
Figure D-1. Summary of RS-232 Connections  
D-2  
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RS-232 Cabling  
Appendices D  
RS43 CABLE  
(NULL MODEM)  
HYDRA  
PC  
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
DCD  
Rx  
Rx  
Tx  
Tx  
DTR  
GND  
DSR  
RTS  
CTS  
DTR  
GND  
DSR  
RTS  
CTS  
RI  
RS-232C  
DB-9  
DB-9  
COM  
KEY  
PINS  
DCD – DATA CARRIER DETECT  
Rx – RECEIVE  
FEMALE  
MALE  
Tx – TRANSMIT  
DTR – DATA TERMINAL READY  
GND – GROUND  
DSR – DATA SET READY  
RTS – REQUEST TO SEND  
CTS – CLEAR TO SEND  
RI – RING INDICATOR  
op73f.eps  
Figure D-2. Hydra Series II (DB-9) to PC (DB-9) RS-232 Connection (Generic)  
D-3  
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2635A  
Users Manual  
RS40 CABLE  
(OR EQUAL)  
PC  
1
2
Tx  
3
Rx  
4
RTS  
CTS  
DSR  
GND  
DCD  
5
6
7
HYDRA  
8
1
2
3
4
5
6
7
8
9
9
Rx  
Tx  
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
21  
22  
23  
24  
25  
DTR  
GND  
DSR  
RTS  
CTS  
RS-232C  
DB-9  
DTR  
RI  
KEY  
PINS  
FEMALE  
Tx – TRANSMIT  
Rx – RECEIVE  
MALE  
RTS – REQUEST TO SEND  
CTS – CLEAR TO SEND  
DSR – DATA SET READY  
GND – GROUND  
DCD – DATA CARRIER DETECT  
DTR – DATA TERMINAL READY  
RI – RING INDICATOR  
DB-25  
COM  
op74f.eps  
Figure D-3. Hydra (DB-9) to PC (DB-25) RS-232 Connection  
D-4  
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RS-232 Cabling  
Appendices D  
RS41 CABLE  
(OR EQUAL)  
MODEM  
1
2
Tx  
3
Rx  
4
RTS  
CTS  
DSR  
GND  
DCD  
5
6
7
HYDRA  
8
1
2
3
4
5
6
7
8
9
9
Rx  
Tx  
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
21  
22  
23  
24  
25  
DTR  
GND  
DSR  
RTS  
CTS  
RS-232C  
DB-9  
DTR  
RI  
KEY  
PINS  
FEMALE  
Tx – TRANSMIT  
Rx – RECEIVE  
MALE  
RTS – REQUEST TO SEND  
CTS – CLEAR TO SEND  
DSR – DATA SET READY  
GND – GROUND  
DB-25  
DCD – DATA CARRIER DETECT  
DTR – DATA TERMINAL READY  
RI – RING INDICATOR  
op75f.eps  
Figure D-4. Hydra Series II (DB-9 to Modem (DB-25) RS-232 Connection  
D-5  
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2635A  
Users Manual  
RS42 CABLE  
(OR EQUAL)  
PRINTER  
1
2
Tx  
Rx  
3
4
RTS  
5
CTS  
DSR  
GND  
DCD  
6
7
HYDRA  
8
1
2
3
4
5
6
7
8
9
9
Rx  
Tx  
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
21  
22  
23  
24  
25  
DTR  
GND  
DSR  
RTS  
CTS  
RS-232C  
DB-9  
DTR  
RI  
KEY  
PINS  
FEMALE  
Tx – TRANSMIT  
Rx – RECEIVE  
MALE  
RTS – REQUEST TO SEND  
CTS – CLEAR TO SEND  
DSR – DATA SET READY  
GND – GROUND  
DB-25  
DCD – DATA CARRIER DETECT  
DTR – DATA TERMINAL READY  
RI – RING INDICATOR  
op76f.eps  
Figure D-5. Hydra Series II (DB-9) to Printer (DB-25) RS-232 Connection  
D-6  
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RS-232 Cabling  
Appendices D  
6
7
8
9
6
5
SOLDER  
SIDE  
CONNECTOR  
SIDE  
1
2
3
4
5
MALE  
FEMALE  
9
8
7
CONNECTOR  
SIDE  
SOLDER  
SIDE  
5
4
3
2
1
DB-9  
CONNECTOR  
13 12 11 10  
9
8
7
6
4
3
2
1
SOLDER  
SIDE  
CONNECTOR  
SIDE  
25 24 23 22 21 20 19 18 17 16 15 14  
MALE  
FEMALE  
1
2
3
4
5
6
7
8
9
10 11  
13  
12  
CONNECTOR  
SIDE  
SOLDER  
SIDE  
14 15 16 17 18 19 20 21 22 23 24 25  
DB-25  
CONNECTOR  
op77f.eps  
Figure D-6. RS-232 DB-9 and DB-25 Connectors  
D-7  
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2635A  
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D-8  
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Appendix E  
8-Bit Binary-Coded-Decimal Table  
E-1  
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2635A  
Users Manual  
Table E-1. 8-Bit Binary-Coded-Decimal  
Binary  
Binary  
Binary  
Binary  
7
6
5
4
3
2
1
0
Dec  
7
6
5
4
3
2
1
0
Dec  
7
6
5
4
3
2
1
0
Dec  
7
6
5
4
3
2
1
0
Dec  
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
000  
001  
002  
003  
004  
005  
006  
007  
008  
009  
010  
011  
012  
013  
014  
015  
016  
017  
018  
019  
020  
021  
022  
023  
024  
025  
026  
027  
028  
029  
030  
031  
032  
033  
034  
035  
036  
037  
038  
039  
040  
041  
042  
043  
044  
045  
046  
047  
048  
049  
050  
051  
052  
053  
054  
055  
056  
057  
058  
059  
060  
061  
062  
063  
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
064  
065  
066  
067  
068  
069  
070  
071  
072  
073  
074  
075  
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118  
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120  
121  
122  
123  
124  
125  
126  
127  
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
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0
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0
1
0
1
0
1
0
1
0
1
128  
129  
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132  
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189  
190  
191  
1
1
1
1
1
1
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1
1
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1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
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1
1
1
1
1
1
1
1
1
1
1
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1
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1
1
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1
1
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1
1
1
1
1
1
1
1
1
1
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1
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1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
192  
193  
194  
195  
196  
197  
198  
199  
200  
201  
202  
203  
204  
205  
206  
207  
208  
209  
210  
211  
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213  
214  
215  
216  
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220  
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223  
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237  
238  
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241  
242  
243  
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248  
249  
250  
251  
252  
253  
254  
255  
E-2  
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Appendix F  
Memory Card File Formats  
Introduction  
This appendix contains a description of the format of the binary files created by the  
2635A Data Bucket. This information is intended to describe the contents in enough  
detail to allow someone well versed in a software programming language to use this  
information to write software to read and interpret the Data Bucket scan data files. (This  
example ;uses the ANSI C Language to examples of decoding and interpreting the file  
data. This code can be compiled using the Microsoft C Compiler on an MS-DOS PC or  
compatible.)  
Data File Format  
The data file format consists of two parts: a header, including the Data Bucket  
configuration during the time the data was gathered: followed by any scan data collected.  
Setup File Format  
The setup file format is very similar to the data file format. The only differences are the  
byte at offset zero has a value of 0 instead of 1, and there is never any scan data (the file  
always ends at offset 729).  
The details of the Hydra Data Bucket binary file configuration format are as follows. A  
good familiarity with the operation of the Hydra Data Bucket will be necessary to  
understand much of the configuration information. For the most part, however, it is not  
necessary to understand all of the configuration information to be able to successfully  
manipulate the scan data. The references are to compute interface commands in Chapter  
4.  
F-1  
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2635A  
Users Manual  
Offset Description  
=====  
0
===========  
File type; 0 for setup files, 1 for data files.  
File format; always zero for this format.  
Tag string. Copied from the setup file used with a time  
string appended; or just a time string if no setup file used.  
Set up format version; always zero.  
1
2-81  
82  
83  
Global instrument configuration; 0x01 bit set for degrees  
Fahrenheit, else Centigrade; 0x02 bit set for open  
thermocouple checking enabled; 0x80 bit set for alarms on open  
thermocouple. See TEMP_CONFIG.  
Measurement rate; 0 for slow, 1 for fast. See RATE.  
Trigger type; 0 for off, 1 for on, 2 for monitor alarm. See  
TRIGGER.  
84  
85  
86  
87  
88  
89  
90  
91  
92  
93  
94  
Output format type; 1 for no units, 2 for units. See FORMAT.  
Totalizer debounce; 0 for off, 1 for on. See TOTAL_DBNC.  
Interval BCD hours. See INTERVAL.  
Interval BCD minutes.  
Interval BCD seconds.  
Event Status Register (ESR) value.  
Service Request Enable (ESE) register value.  
Instrument Event Enable (IEE) register value.  
Logging status; 0x1 bit set if logging enabled, 0x02 bit  
set if LOG queue stops logging when full. See LOG_MODE.  
Logging filter; 0 for all, 1 for alarms, 2 for alarm  
transitions. See PRINT_TYPE.  
95  
96  
97  
Logging destination; 0x01 bit for printer, 0x02 bit set for  
LOG queue, 0x04 bit set for memory card. See PRINT_TYPE.  
Front panel lock mode; 0 for not locked, 3 for  
configuration lock. See LOCK.  
98-727 Channel definitions:  
Offset within each channel definition  
Description  
———------——  
———  
0
Measurement. 0 if off, 1 if vdc, 2 if vac, 3 if  
ohms, 4 if frequency, 9 if thermocouple, 11 if RTD.  
Measurement range. Lower bit values are measurement  
range, with 0 being the lowest range for the  
measurement type (e.g., 0 for 300 mVDC).  
0x10 bit set if autoranging. See RANGE?  
Thermocouple/RTD type. 0 for Pt, 1 for J, 2 for K,  
3 for E, 4 for T, 5 for N, 6 for R, 7 for S, 8 for  
B, 9 for C.  
1
2
3
Alarm flags. 0x01 bit set for limit 1 (SP1) low, 0x02  
bit set for SP1 high, 0x04 bit set for limit 2 (SP2)  
low, 0x08 bit set for SP2 high. See ALARM_LIMIT.  
Alarm limit 1 (4-byte single-precision floating point).  
Alarm limit 2 (4-byte single-precision floating point).  
Alarm 1 digital I/O association. See ALARM_ASSOC.  
Alarm 1 display range. See SCALE_MB (DISPLAY CODE - 1).  
Alarm 2 digital I/O association. See ALARM_ASSOC.  
Alarm 2 display range. See SCALE_MB (DISPLAY CODE - 1).  
Mx+B M value (floating point).  
4-7  
8-11  
12  
13  
14  
15  
16-19  
20-23  
24  
Mx+B B value (floating point).  
Mx+B M display range. See SCALE_MB (DISPLAY CODE - 1).  
MX+B B display range. See SCALE_MB (DISPLAY CODE - 1).  
RTD R0 value (floating point). See RTD_R0.  
25  
26-29  
728-729 CRC-16 of the data from offset 82 to 727.  
F-2  
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Appendices  
Memory Card File Formats  
F
For a data file, any scan data would immediately follow the configuration information.  
Note that it is very possible to have no scan data if the data file is created but scanning is  
never done.  
Measurements are stored in scan records of variable size. The contents of each record is  
as follows:  
Offset Description  
===== ===========  
0
1
Time BCD hours. See TIME_DATE?  
Time BCD minutes.  
2
3
Time BCD seconds.  
Date BCD month.  
4
5
Date BCD day.  
Date BCD year.  
6
7
8-11  
Alarm output values. See ALARM_DO_LEVELS?  
Digital Input/Output values. See DIO_LEVELS?  
Totalizer value, 4-byte single precision floating point.  
12-on Measurement values, from 1 to 21 4-byte single precision  
floating-point numbers.  
The number of floating point values per scan is the number of non-off channels in the  
channel configuration data. The number of scans per file varies from zero to tens of  
thousands, but will always be an integral number (there will be no partial scans).  
Example  
The following as an example of how the configuration and scan data can be interpreted  
using the C programming language. The C code shown here can be incorporated into a C  
program and used to access the information contained in Hydra Data Bucket data files.  
These examples can not, however be compiled and used as they are. They are not meant  
to be complete C programs.  
This first part of the example creates a structure named ‘hydra’ that will hold the  
configuration information read from the data file.  
F-3  
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2635A  
Users Manual  
/* Hydra Data Bucket data file format: */  
struct hydra_config {  
unsigned char file_type;  
unsigned char file_format;  
unsigned char tag[80];  
unsigned char setup_format;  
unsigned char system;  
unsigned char rate;  
unsigned char trigger;  
unsigned char format;  
unsigned char total_debounce;  
unsigned char interval_bcd_hours;  
unsigned char interval_bcd_minutes;  
unsigned char interval_bcd_seconds;  
unsigned char ese;  
unsigned char sre;  
unsigned char iee;  
unsigned char log_status;  
unsigned char log_filter;  
unsigned char log_dest;  
unsigned char lock;  
struct hydra_chan {  
unsigned char function;  
unsigned char range;  
unsigned char temperature;  
unsigned char alarm_flags;  
float alarm_limit_1;  
float alarm_limit_2;  
unsigned char alarm_assoc_1;  
unsigned char alarm_dr_1;  
unsigned char alarm_assoc_2;  
unsigned char alarm_dr_2;  
float m;  
float b;  
unsigned char m_dr;  
unsigned char b_dr;  
float rtd_r0;  
} chan[21];  
} hydra;  
/*  
** A count of the number of channel measurements in each scan record will  
** be needed. Also, a table to determine the proper channel number for  
** each measurement will be created while getting the channel configuration  
** information.  
*/  
int max_index;  
int index_to_chan[21];  
F-4  
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Appendices  
Memory Card File Formats  
F
The following function will copy the configuration information from the data file into  
the ‘hydra’ structure, keeping track of the number of configured channels and filling the  
channel index table as it goes. It assumes that the first 730 bytes of the file have already  
been read into memory using the read () library function, or similar.  
/*  
-* convert_config(): Convert the file configuration data into C variables.  
**  
** Inputs:  
**  
**  
file_data  
Pointer to the first 730 bytes of data  
from a Hydra Data Bucket file.  
** Outputs:  
**  
**  
**  
**  
**  
hydra  
Global variable set to the configuration  
found in the file data.  
number of channels in scan record and  
the table of non-off channels  
max_index  
index_to_chan  
** Returns:  
**  
*/  
number of bytes per scan record.  
int  
convert_config(unsigned char * file_data)  
{
int ch;  
/* Must be a data file (file_type must = 1) */  
hydra.file_type = *file_data++;  
/* Must be version 0 format */  
hydra.file_format = *file_data++;  
/* Copy tag */  
memcpy(hydra.tag, file_data, 80);  
file_data += 80;  
/* Must be configuration format zero */  
hydra.setup_format = *file_data++;  
/* Convert global configuration */  
hydra.system = *file_data++;  
hydra.rate = *file_data++;  
hydra.trigger = *file_data++;  
hydra.format = *file_data++;  
hydra.total_debounce = *file_data++;  
hydra.interval_bcd_hours = *file_data++;  
hydra.interval_bcd_minutes = *file_data++;  
hydra.interval_bcd_seconds = *file_data++;  
hydra.ese = *file_data++;  
hydra.sre = *file_data++;  
hydra.iee = *file_data++;  
hydra.log_status = *file_data++;  
hydra.log_filter = *file_data++;  
hydra.log_dest = *file_data++;  
hydra.lock = *file_data++;  
/* Convert channel configurations */  
/* Count number of non-off channels during conversion */  
max_index = 0;  
for (ch=0; ch < 21; ch++) {  
F-5  
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hydra.chan[ch].function = *file_data++;  
hydra.chan[ch].range = *file_data++;  
hydra.chan[ch].temperature = *file_data++;  
hydra.chan[ch].alarm_flags = *file_data++;  
file_data += convert_float(&hydra.chan[ch].alarm_limit_1,  
file_data);  
file_data += convert_float(&hydra.chan[ch].alarm_limit_2,  
file_data);  
hydra.chan[ch].alarm_assoc_1 = *file_data++;  
hydra.chan[ch].alarm_dr_1 = *file_data++;  
hydra.chan[ch].alarm_assoc_2 = *file_data++;  
hydra.chan[ch].alarm_dr_2 = *file_data++;  
file_data += convert_float(&hydra.chan[ch].m, file_data);  
file_data += convert_float(&hydra.chan[ch].b, file_data);  
hydra.chan[ch].m_dr = *file_data++;  
hydra.chan[ch].b_dr = *file_data++;  
file_data += convert_float(&hydra.chan[ch].rtd_r0, file_data);  
/* Create index to channel conversion table */  
if (hydra.chan[ch].function != 0) {  
index_to_chan[max_index++] = ch;  
}
}
/* Ignore trailing CRC bytes */  
/* return number of bytes per scan record */  
return (4 * max_index + 12);  
}
/*  
-* convert_float(): Convert binary data stream to a floating point variable  
**  
** This routine assumes that both input and output are four-byte IEEE  
** single-precision data in the DOS (Intel x86) architecture. This  
** is very machine dependent. You may need to change this routine to  
** fit the needs of your architecture.  
**  
** Inputs:  
**  
**  
**  
float_dest  
src  
Pointer to C floating point variable (destination).  
Pointer to four bytes of binary file data.  
** Outputs:  
**  
float_dest  
Set to a floating point value.  
**  
** Returns:  
**  
*/  
Number of bytes consumed (4)  
int  
convert_float(float * dest, unsigned char * src)  
{
unsigned char * byte_dest = (unsigned char *) dest;  
*byte_dest++ = *src++;  
*byte_dest++ = *src++;  
*byte_dest++ = *src++;  
*byte_dest = *src;  
return sizeof(float);  
}
F-6  
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Appendices  
Memory Card File Formats  
F
Now that the configuration has been processed and the number of valid channels has  
been determined, the scan data can be processed.  
/* Measurements are stored in scan records of variable size.  
** This C structure is the decoded version of a scan record,  
** and is of fixed size (unused measurement values are not set).  
*/  
struct scan_record {  
/* Timestamp */  
unsigned char bcd_hours;  
unsigned char bcd_minutes;  
unsigned char bcd_seconds;  
unsigned char bcd_month;  
unsigned char bcd_day;  
unsigned char bcd_year;  
/* Digital (alarm) outputs */  
unsigned char dout;  
/* Digital input/outputs */  
unsigned char dio;  
/* Totalizer value */  
float total;  
/* Measurement per channel */  
float meas[21];  
} scan;  
/*  
-* convert_scan_record(): Convert a scan record into usable data  
**  
** In each data file, after the 730 bytes of configuration data, an  
** array of scan records may be found (it is possible for data files  
** to have no scan data). This routine converts a single scan record  
** and places it in the given destination buffer.  
**  
** Note that convert_config() must be called before this routine!  
**  
** Inputs:  
**  
**  
**  
**  
**  
**  
**  
**  
**  
**  
hydra  
File configuration data.  
number of channels in scan record and  
the table of non-off channels  
A single scan record from the same data file.  
that was last processed by convert_config().  
Note that this routine assumes that the  
number of bytes in this buffer is exactly the  
number of bytes per scan record.  
max_index  
index_to_chan  
file_data  
scan  
Pointer to destination scan record buffer.  
** Outputs:  
**  
*/  
scan  
Set to converted version of scan record.  
void  
convert_scan_record(unsigned char * file_data, struct scan_record * scan)  
{
int index;  
int ch;  
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/* Set timestamp */  
scan->bcd_hours = *file_data++;  
scan->bcd_minutes = *file_data++;  
scan->bcd_seconds = *file_data++;  
scan->bcd_month = *file_data++;  
scan->bcd_day = *file_data++;  
scan->bcd_year = *file_data++;  
/* Get digital I/O and totalizer values */  
scan->dout = *file_data++;  
scan->dio = *file_data++;  
file_data += convert_float(&scan->total, file_data);  
/* Get measurement for each non-off channel in this scan */  
for (index=0; index < max_index; index++) {  
/* Convert index to channel */  
ch = index_to_chan[index];  
/* Read this channel’s scan data */  
file_data += convert_float(&scan->meas[ch], file_data);  
}
}
Using the above routines to decode the configuration of a data file and get the contents  
of the first scan record will require something like the following:  
char * file = “DAT00.HYD”;  
int fd;  
unsigned char buf[730];  
int record_size;  
/* Open the binary data file name pointed to by “file” */  
fd = open(file, (O_RDONLY | O_BINARY));  
/* Read and interpret the configuration header in the file */  
read(fd, buf, 730);  
record_size = convert_config(buf);  
/* Read and convert the scan measurements */  
read(fd, buf, record_size);  
convert_scan_record(buf, &scan);  
F-8  
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Appendix G  
True RMS Measurements  
Introduction  
The instrument measures the true value of ac voltages. In physical terms, the rms (root-  
means-square) value of a waveform is the equivalent dc value that causes the same  
amount of hear to be dissipated in a resistor. True rms measurement greatly simplifies  
the analysis of complex ac signals. Since the rms value is the dc equivalent of the  
original waveform, it provides a reliable basis for comparing dissimilar waveforms.  
Effect of Internal Noise in AC Measurements  
With the input shorted and the channel set for ac volts (VAC) measurement, internal  
amplifier noise causes a typical display reading of approximately 0.50 mv ac. Since the  
instrument is a true rms responding measurement device, this noise contributes  
minimally to the readings at the specified floor of each range. When the rms value of the  
two signals (internal noise and range floor) is calculated, the effect of the noise is shown  
as:  
Total rms digits = Square Root of (0.502 + 15.002) = 15.008  
The display will read 15.01. At the 28.00 mV input level on the 300.00 mV range in the  
slow rate, the display will read 28.00 with no observable error.  
Waveform Comparison (True RMS VS Average Responding)  
Figure H-1 illustrates the relationship between ac and dc components for common  
waveforms and compares readings for true rms measurements (Hydra) and average-  
responding measurements. For example, consider the first waveform, a 1.41421V (zero-  
to-peak) sine wave. Both the instrument and rms-calibrated average-responding  
measurement devices display the correct rms reading of 1.0000V ac (the dc component  
equals ). However, consider the 2V (peak-to peak) square wave.  
Both types of measurement correctly display the dc component (0V), but the instrument  
also correctly measures the ac component (1.0000V). The average-responding device  
measures 1.11V, which amounts to an 11% error.  
Average-responding measurement devices have been in use for a long time; you may  
have accumulated test or reference data based on such instruments. The conversion  
factors in Figure G-1 can help in converting between the two measurement methods.  
G-1  
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2635A  
Users Manual  
PEAK VOLTAGES  
MEASURED VOLTAGES  
AC COMPONENT ONLY  
DC AND AC  
TOTAL RMS  
AC-COUPLED  
INPUT  
WAVEFORM  
DC  
TRUE RMS =  
ac2 + dc2  
COMPONENT  
ONLY  
PK-PK  
2.828  
0-PK  
RMS CAL*  
HYDRA  
SINE  
1.414  
PK  
0
1.000  
PK-PK  
1.000  
0.000  
0.900  
1.000  
1.000  
1.000  
RECTIFIED SINE  
(FULL WAVE)  
1.414  
2.000  
1.414  
2.000  
0.421  
0.779  
PK  
0.436  
PK-PK  
0
RECTIFIED SINE  
(HALF WAVE)  
PK  
0.771  
1.000  
PK-PK  
0.636  
0.000  
0.707  
0
SQUARE  
PK  
2.000  
1.414  
2.000  
1.000  
1.414  
1.111  
0.785  
0
PK-PK  
1.000  
1.000  
RECTIFIED  
SQUARE  
PK-PK  
0.707  
PK  
0
RECTANGULAR  
PULSE  
2.000  
PK  
4.442 K2  
PK-PK  
X
0
2K  
Y
2D  
D = X/Y  
K = D-D2  
2 D  
TRIANGLE  
SAWTOOTH  
3.464  
1.732  
PK  
0.962  
1.000  
0
PK-PK  
0.000  
1.000  
*
RMS CAL IS THE DISPLAYED VALUE FOR AVERAGE RESPONDING INSTRUMENTS THAT ARE CALIBRATED  
TO DISPLAY RMS FOR SINE WAVES  
078f.eps  
Figure G-1. Comparison of Common Waveforms  
G-2  
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Hydra Configuration Record  
SET-UP NAME_________________________________________ DATE_________________________  
SCAN RATE:  
q Slow  
q Fast  
TEMPERATURE UNITS q °C q°F  
RS-232-C COMMUNICATION  
SCAN INTERVAL:_______ :_______: _______  
Baud Rate q 38400 q 19200 q 9600 q 4800  
q 2400  
Parity q Even  
q
q
q
q
1200 q 600 q 300  
OUTPUT:  
q Printer  
Odd  
Off  
q None  
q Memory  
CTS  
Echo  
q On  
q On  
Mode: q All Data  
Off  
q Alarm Data  
q Alarm Transition Data  
TRIGGERS:  
q Off  
q External q Monitor Alarm Ch# ____ Totalizer Debounce q On q Off  
Chan  
Input Name  
Type  
Range  
LIM 1  
Alarm  
LIM 2  
Alarm  
M
B
Output  
Output  
0
0
0
1
1
1
2
2
2
3
3
3
4
4
4
5
5
5
6
6
6
7
7
7
8
8
8
9
9
9
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
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Hydra Memory Card Record  
DATA FILES  
Application  
SET-UP FILES  
Application  
DATxx  
Note  
SETxx  
Note  
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Index  
channel integrity test, 7-8  
cleaning, 7-3  
Clearing alarm parameters from a channel, 2-19  
Clearing Mx+B scaling from a channel, 2-23  
Common mode rejection, A-10  
—2—  
2-wire accuracy, A-8, A-12  
computer interface command set, 4-18  
computer interface commands and  
—A—  
AC operation, 1-13  
Ac signal cross talk in a dc voltage channel, B-1  
Ac signal cross talk into a frequency  
Ac signal cross talk into an ac voltage  
channel, B-2  
Ac signal cross talk into an ohms channel, B-2  
Ac signal crosstalk into a temperature  
channel, B-3  
AC Voltage Measurements, A-8  
accuracy verification test, 7-7  
adjusting the handle, 1-12  
computer operation, 1-8  
configuring a channel to measure ac volts, 2-10  
configuring a channel to measure dc volts, 2-9  
configuring a channel to measure frequency, 2-12  
configuring a channel to measure resistance, 2-11  
configuring a measurement channel, 2-8  
configuring for printer operations, 5-5  
configuring the instrument for computer  
operations, 4-5  
configuring the instrument for modem  
operations, 6-7  
configuring the instrument for operation, 2-6  
configuring the instrument modem for modem  
operations, 6-4  
Alarm indications while monitoring, 2-19  
Alarm indications while reviewing, 2-19  
Alarm indications while scanning, 2-18  
Alarm outputs, 1-17  
configuring the pc for computer operations, 4-6  
connecting the instrument to a pc, 4-3  
connecting the instrument to a power  
alarm outputs and digital I/O, 1-9  
alarm outputs connections, 1-17  
Alarm outputs for channel 0 to 3 using the alarm  
outputs connector, 2-19  
connecting the instrument to a printer, 5-3  
connecting the modem to a pc for modem  
configuration, 6-4  
Alarm outputs for channels 4 to 20 using the  
digital I/O connector, 2-19  
alarms, 1-9  
connecting the modem to an instrument, 6-6  
connector set, 2620a-100, 1-10  
controls and indicators, 1-19  
crosstalk, 1-14  
Cross-talk rejection, A-8  
Alarms and autoprinting, 2-20  
Alarms and monitor-alarm triggering, 2-20  
Alarms and Mx+B scaling, 2-20  
applications software, 1-9  
—C—  
—D—  
calibration, 7-21  
data file procedures, 3-12  
changing the memory card during scanning, 3-5  
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DC operation, 1-13  
memory card capacity, 3-4  
Memory card capacity, 2-26  
Memory card data extraction, 2-27  
Memory card exchange during scanning, 2-26  
memory card file operations to and  
Decoding the ascii string, C-1  
dedicated alarm output test, 7-18  
digital I/O connections, 1-18  
Digital input test, 7-16  
Digital output test, 7-15  
Memory card files, 2-26  
Memory card formatting, 2-26  
memory card operation, 1-7  
modem operation, 1-8  
Monitor-alarm trigger, 2-31  
Mx+B scaling, 1-9  
—E—  
Examples, 2-23  
External trigger input, 1-17  
external trigger input test, 7-21  
—O—  
open thermocouple response test, 7-11  
operating modes, 1-5, 2-26  
—F—  
Floating point conversion, C-4  
four-terminal resistance test, 7-10  
front panel controls, 1-19  
front panel indicators, 1-19  
front panel operation, 1-7  
—P—  
performance tests, 7-4  
printer operation, 1-8  
printing measurement data and memory card  
directory, 5-6  
printing measurement results during  
printing the directory of the memory card, 5-9  
printing the review array, 5-8  
—H—  
how the instrument processes input, 4-12  
how the instrument processes output, 4-13  
hydra logger package, 1-10  
hydra starter package, 1-10  
—R—  
Rate, A-14  
recording measurement results during  
—I—  
initializing a memory card, 3-7  
removing a memory card, 3-5  
Resistance temperature detectors  
Resistance-temperature detectors, 2-13  
RTD temperature accuracy test, 7-13  
RTD temperature accuracy test (using decade  
resistance source), 7-13  
Input debouncing, A-14  
input string examples, 4-13  
input terminators, 4-12  
inserting a memory card, 3-5  
inserting and removing the memory card, 3-5  
installing or replacing the memory card  
battery, 3-5  
Instrument event register (IER), 4-14  
Isolation, A-14  
RTD temperature accuracy test (using DIN/IEC  
—S—  
—L—  
selecting a channel, 2-8  
selftest diagnostics and error codes, 7-4  
sending numeric values to the instrument, 4-13  
Sensitivity, A-12  
line fuse, 7-3  
—M—  
setting the memory card write-protect  
Maximum autoranging time, A-14  
measurement capabilities, 1-9  
Memory card as a data destination, 2-26  
memory card battery, 3-5  
setting the Mx+B scaling, 2-23  
2
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Index (continued)  
setting up the instrument, 1-11  
setup and data file current status, 3-15  
setup and data files directory, 3-14  
setup file procedures, 3-9  
Totalizer input, 1-18  
Totalizer sensitivity test, 7-18  
Standard event status register (ESR), 4-16  
Status byte register (STB), 4-17  
status registers, 4-14  
Totalizing input, A-14  
Triggering options and memory card  
operation, 2-31  
summary of computer operations, 4-3  
summary of front panel operations, 2-5  
summary of memory card operations, 3-3  
summary of modem operations, 6-3  
summary of printer operations, 5-3  
turning the power on, 2-6  
—U—  
universal input module connections, 1-14  
unpacking and inspecting the instrument, 1-11  
—T—  
using data open, 3-12  
using setup load, 3-10  
using setup store, 3-9  
using shielded wiring, 1-14  
using the scan mode, 2-26  
testing the instrument/pc RS-232 interface, 4-6  
testing the RS-232 interface using gwbasic, 4-9  
testing the RS-232 interface using Qbasic, 4-10  
testing the RS-232 interface using terminal  
emulation (generic), 4-7  
testing the RS-232 interface using terminal  
emulation (windows), 4-6  
testing the RS-232/modem interface, 6-8  
thermocouple measurement range accuracy  
test, 7-9  
—V—  
variations in the display, 7-22  
Thermocouple restrictions:, 2-13  
thermocouple temperature accuracy test, 7-10  
Thermocouples, 2-13  
—X—  
xmodem file transfers, 4-18  
Threshold, A-14  
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