National Instruments Stereo Amplifier SC 2040 User Manual
SC-2040  
User Manual  
Eight-Channel Simultaneous Sample-and-Hold Accessory  
September 1994 Edition  
Part Number 371191A-01  
© Copyright 1994 National Instruments Corporation.  
All Rights Reserved.  
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Limited Warranty  
The SC-2040 is warranted against defects in materials and workmanship for a period of one year from the date of  
shipment, as evidenced by receipts or other documentation. National Instruments will, at its option, repair or replace  
equipment that proves to be defective during the warranty period. This warranty includes parts and labor.  
A Return Material Authorization (RMA) number must be obtained from the factory and clearly marked on the  
outside of the package before any equipment will be accepted for warranty work. National Instruments will pay the  
shipping costs of returning to the owner parts which are covered by warranty.  
National Instruments believes that the information in this manual is accurate. The document has been carefully  
reviewed for technical accuracy. In the event that technical or typographical errors exist, National Instruments  
reserves the right to make changes to subsequent editions of this document without prior notice to holders of this  
edition. The reader should consult National Instruments if errors are suspected. In no event shall National  
Instruments be liable for any damages arising out of or related to this document or the information contained in it.  
EXCEPT AS SPECIFIED HEREIN, NATIONAL INSTRUMENTS MAKES NO WARRANTIES, EXPRESS OR IMPLIED,  
AND SPECIFICALLY DISCLAIMS ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR  
PURPOSE. CUSTOMER'S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART  
OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER.  
NATIONAL INSTRUMENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA, PROFITS,  
USE OF PRODUCTS, OR INCIDENTAL OR CONSEQUENTIAL DAMAGES, EVEN IF ADVISED OF THE POSSIBILITY  
THEREOF. This limitation of the liability of National Instruments will apply regardless of the form of action,  
whether in contract or tort, including negligence. Any action against National Instruments must be brought within  
one year after the cause of action accrues. National Instruments shall not be liable for any delay in performance due  
to causes beyond its reasonable control. The warranty provided herein does not cover damages, defects,  
malfunctions, or service failures caused by owner's failure to follow the National Instruments installation, operation,  
or maintenance instructions; owner's modification of the product; owner's abuse, misuse, or negligent acts; and  
power failure or surges, fire, flood, accident, actions of third parties, or other events outside reasonable control.  
Copyright  
Under the copyright laws, this publication may not be reproduced or transmitted in any form, electronic or  
mechanical, including photocopying, recording, storing in an information retrieval system, or translating, in whole  
or in part, without the prior written consent of National Instruments Corporation.  
Trademarks  
®
LabVIEW®, NI-DAQ , and RTSI® are trademarks of National Instruments Corporation.  
Product names and company names listed are trademarks or trade names of their respective companies.  
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Warning Regarding Medical and Clinical Use  
of National Instruments Products  
National Instruments products are not designed with components and testing intended to ensure a level of reliability  
suitable for use in treatment and diagnosis of humans. Applications of National Instruments products involving  
medical or clinical treatment can create a potential for accidental injury caused by product failure, or by errors on  
the part of the user or application designer. Any use or application of National Instruments products for or involving  
medical or clinical treatment must be performed by properly trained and qualified medical personnel, and all  
traditional medical safeguards, equipment, and procedures that are appropriate in the particular situation to prevent  
serious injury or death should always continue to be used when National Instruments products are being used.  
National Instruments products are NOT intended to be a substitute for any form of established process, procedure, or  
equipment used to monitor or safeguard human health and safety in medical or clinical treatment.  
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Contents  
About This Manual................................................................................................................ix  
Organization of This Manual............................................................................................ix  
Conventions Used in This Manual....................................................................................x  
The National Instruments Documentation Set..................................................................x  
Related Documentation ....................................................................................................xi  
Customer Communication ................................................................................................xi  
Chapter 1  
Introduction.......................................................................................................................... 1-1  
About the SC-2040.........................................................................................................1-1  
What You Need to Get Started ......................................................................................1-1  
Software Programming Choices ....................................................................................1-2  
LabVIEW and LabWindows Application Software ..........................................1-2  
NI-DAQ Driver Software...................................................................................1-2  
Register-Level Programming.............................................................................1-4  
Optional Equipment.......................................................................................................1-4  
Unpacking......................................................................................................................1-4  
Chapter 2  
Configuration and Installation....................................................................................... 2-1  
Board Configuration ......................................................................................................2-1  
Supplementary Configuration Information........................................................2-6  
Power Supply Selection.........................................................................2-6  
Shield Selection......................................................................................2-6  
DAQ Board Ground Isolation Selection................................................2-6  
Gain Selection....................................................................................................2-6  
Input Mode Selection.........................................................................................2-7  
Installation......................................................................................................................2-8  
Power On Sequence.......................................................................................................2-8  
Chapter 3  
Signal Connections ............................................................................................................. 3-1  
I/O Connector Pin Description.......................................................................................3-1  
Signal Connection Description ..........................................................................3-4  
Analog Signal Input...........................................................................................3-7  
DC-Coupled Inputs................................................................................3-7  
AC-Coupled Signals ..............................................................................3-8  
Analog Input Ranges..................................................................3-10  
Digital Signal Input............................................................................................3-11  
Monitoring Signal Outputs.................................................................................3-11  
Other Connection Considerations..................................................................................3-11  
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Contents  
Chapter 4  
Theory of Operation .......................................................................................................... 4-1  
Functional Overview......................................................................................................4-1  
Analog Circuitry ............................................................................................................4-3  
Input Protection..................................................................................................4-3  
Amplification.....................................................................................................4-3  
Track-and-Hold (T/H) Circuitry ........................................................................4-3  
Triggering from the DAQ Board ...........................................................4-4  
External Triggering................................................................................4-5  
Output Connection.................................................................................4-6  
Power Supply.........................................................................................4-6  
Chapter 5  
Calibration Procedures.....................................................................................................5-1  
Software Calibration......................................................................................................5-1  
Offset Adjustment..............................................................................................5-1  
Gain Adjustment................................................................................................5-2  
Linearity Adjustment .........................................................................................5-2  
Hardware Calibration.....................................................................................................5-2  
Appendix A  
Specifications........................................................................................................................ A-1  
Appendix B  
Customer Communication............................................................................................... B-1  
Glossary........................................................................................................................Glossary-1  
Index..................................................................................................................................Index-1  
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Contents  
Figures  
Figure 1-1. The Relationship between the Programming Environment,  
NI-DAQ, and Your Hardware............................................................................. 1-3  
Figure 2-1. SC-2040 Parts Locator Diagram..........................................................................2-2  
Figure 3-1. SC-2040 I/O Connectors J11 and J12..................................................................3-2  
Figure 3-2. SC-2040 Signal Routing......................................................................................3-6  
Figure 3-3. Ground-Referenced Signal Connection...............................................................3-7  
Figure 3-4. Floating Signal Connection .................................................................................3-8  
Figure 3-5. Ground-Referenced AC-Coupled Signal Connection .........................................3-9  
Figure 3-6. Ground-Offset AC-Coupled Signal Connection..................................................3-9  
Figure 3-7. Floating AC-Coupled Signal Connection............................................................3-10  
Figure 4-1. SC-2040 Block Diagram......................................................................................4-2  
Figure 4-2. T/H Amplifier Hold Settling Time and Track Acquisition Time........................4-4  
Figure 4-3. MIO-16E Controlled Triggering..........................................................................4-5  
Figure 4-4. External Triggering..............................................................................................4-6  
Tables  
Table 2-1. Power Supply Selection.......................................................................................2-3  
Table 2-2. Shield Selection...................................................................................................2-4  
Table 2-3. DAQ Board Ground Isolation Selection..............................................................2-4  
Table 2-4. Channel Gain Selection .......................................................................................2-5  
Table 2-5. Channel Input Mode............................................................................................2-5  
Table 2-6. Gain Switches for Each Channel.........................................................................2-6  
Table 2-7. Switch Settings for Gain Selection......................................................................2-7  
Table 2-8. Input Mode Selection Jumpers ............................................................................2-7  
Table 3-1. Pin Assignments for Connectors J11 and J12......................................................3-3  
Table 3-2. Input Connectors Signal Summary......................................................................3-4  
Table 3-3. Output Connectors (J11 and J12) Signal Summary.............................................3-4  
Table 5-1. Calibration Component Identification.................................................................5-3  
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About This Manual  
This manual describes the electrical and mechanical aspects of the SC-2040 and contains  
information concerning its configuration and operation. The SC-2040 is an eight-channel  
simultaneously sampling differential amplifier for the National Instruments MIO-16E Series  
DAQ boards. The SC-2040 samples all eight channels at the same time, preserving interchannel  
phase relationships for the MIO-16E.  
Organization of This Manual  
The SC-2040 User Manual is organized as follows:  
•
•
Chapter 1, Introduction, describes the SC-2040, lists what you need to get started with your  
SC-2040, describes the optional software and optional equipment, and explains how to  
unpack your SC-2040.  
Chapter 2, Configuration and Installation, describes the configuration and installation of  
your SC-2040. The topics discussed are switch and jumper configuration, connection of the  
SC-2040 to the MIO-16E, and the power-on sequence for your SC-2040 configuration.  
•
•
•
Chapter 3, Signal Connections, describes the signal connections to the SC-2040 board, and  
cable wiring.  
Chapter 4, Theory of Operation, contains a functional overview of the SC-2040 board and  
explains the operation of each functional unit making up the SC-2040.  
Chapter 5, Calibration Procedures, discusses the calibration procedures for the SC-2040  
board.  
•
•
Appendix A, Specifications, lists the specifications for the SC-2040.  
Appendix B, Customer Communication, contains forms you can use to request help from  
National Instruments or to comment on our products.  
•
•
The Glossary contains an alphabetical list and description of terms used in this manual,  
including abbreviations, acronyms, metric prefixes, mnemonics, and symbols.  
The Index contains an alphabetical list of key terms and topics used in this manual, including  
the page where you can find each one.  
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About This Manual  
Conventions Used in This Manual  
The following conventions are used in this manual:  
bold italic  
Bold, italic text denotes a note, caution, or warning.  
italic  
Italic text denotes emphasis, a cross reference, or an introduction to a key  
concept.  
MIO-16E  
MIO-16E refers to the National Instruments E-Series of MIO-16 DAQ  
boards unless otherwise noted.  
monospace  
Lowercase text in this font denotes text or characters that are to be literally  
input from the keyboard, sections of code, programming examples, and  
syntax examples. This font is also used for the proper names of disk  
drives, paths, directories, programs, subprograms, subroutines, device  
names, functions, variables, filenames, and extensions, and for statements  
and comments taken from program code.  
Abbreviations, acronyms, metric prefixes, mnemonics, symbols, and terms are listed in the  
Glossary.  
The National Instruments Documentation Set  
The SC-2040 User Manual is one piece of the documentation set for your system. You could  
have any of several types of manuals, depending on the hardware and software in your system.  
Use the manuals you have as follows:  
•
•
Your DAQ hardware user manuals–These manuals have detailed information about the DAQ  
hardware that plugs into or is connected to your computer. Use these manuals for hardware  
installation and configuration instructions, specification information about your DAQ  
hardware, and application hints.  
Software manuals–Examples of software manuals you might have are the LabVIEW and  
LabWindows® manual sets and the NI-DAQ manuals. After you set up your hardware  
system, use either the application software (LabVIEW or LabWindows) manuals or the  
NI-DAQ manuals to help you write your application. If you have a large and complicated  
system, it is worthwhile to look through the software manuals before you configure your  
hardware.  
•
Accessory manuals–If you are using accessory products, read the terminal block and cable  
assembly installation guides or accessory board user manuals. They explain how to  
physically connect the relevant pieces of the system together. Consult these guides when you  
are making your connections.  
SC-2040 User Manual  
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About This Manual  
Related Documentation  
The following document contains information that you may find helpful as you read this manual:  
Your DAQ hardware user manual  
•
Customer Communication  
National Instruments wants to receive your comments on our products and manuals. We are  
interested in the applications you develop with our products, and we want to help if you have  
problems with them. To make it easy for you to contact us, this manual contains comment and  
configuration forms for you to complete. These forms are in Appendix B, Customer  
Communication, at the end of this manual.  
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Chapter 1  
Introduction  
This chapter describes the SC-2040, lists what you need to get started with your SC-2040,  
describes the optional software and optional equipment, and explains how to unpack your  
SC-2040.  
About the SC-2040  
The SC-2040 is an eight-channel simultaneously sampling differential amplifier for the National  
Instruments MIO-16E Series DAQ boards. Each channel provides DIP-switch-selectable gain  
followed by a track-and-hold amplifier. The track-and-hold amplifiers sample all the inputs at  
the same time, which is useful for preserving interchannel phase relationships. The MIO-16E  
can trigger the track-and-hold amplifiers, or you can supply an external trigger source.  
Note: When a board is referred to without an AT prefix (that is, MIO-16E), the reference  
applies to the AT versions of that board.  
The SC-2040 is a circuitboard assembly that is placed on a workbench or mounted in a 19-in.  
rack. You can configure the SC-2040 to draw power from the MIO-16E board or from an  
external +5 V supply. A red LED indicates when the board is powered on. Input signal leads are  
attached at screw terminals.  
What You Need to Get Started  
To set up and use your SC-2040, you will need the following components:  
•
•
•
SC-2040 board  
SC-2040 User Manual  
1.0, 2.0, 5.0, or 10.0 m SH6868 or R6868 cable  
Detailed specifications of the SC-2040 are in Appendix A, Specifications.  
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Introduction  
Chapter 1  
Software Programming Choices  
Your SC-2040 kit does not include software. There are four options to choose from when  
programming your National Instruments DAQ and SCXI hardware. You can use LabVIEW,  
LabWindows, NI-DAQ, or register-level programming software.  
The SC-2040 works with LabVIEW for Windows, LabVIEW for Macintosh, LabWindows for  
DOS, LabWindows/CVI for Windows, NI-DAQ software for PC compatibles, and NI-DAQ  
software for Macintosh.  
LabVIEW and LabWindows Application Software  
LabVIEW and LabWindows are innovative program development software packages for data  
acquisition and control applications. LabVIEW uses graphical programming, whereas  
LabWindows enhances traditional programming languages. Both packages include extensive  
libraries for data acquisition, instrument control, data analysis, and graphical data presentation.  
LabVIEW currently runs on three different platforms–AT/MC/EISA computers running  
Microsoft Windows, the Macintosh platform, and the Sun SPARCstation platform. LabVIEW  
features interactive graphics, a state-of-the-art user interface, and a powerful graphical  
programming language. The LabVIEW Data Acquisition VI Library, a series of VIs for using  
LabVIEW with National Instruments DAQ hardware, is included with LabVIEW. The  
LabVIEW Data Acquisition VI Libraries are functionally equivalent to the NI-DAQ software,  
except that the SCXI functions are not included in the LabVIEW software for Sun.  
LabWindows has two versions–LabWindows for DOS is for use on PCs running DOS, and  
LabWindows/CVI is for use on PCs running Windows and for Sun SPARCstations.  
LabWindows/CVI features interactive graphics, a state-of-the-art user interface, and uses the  
ANSI standard C programming language. The LabWindows Data Acquisition Library, a series  
of functions for using LabWindows with National Instruments DAQ hardware, is included with  
the NI-DAQ software kit. The LabWindows Data Acquisition libraries are functionally  
equivalent to the NI-DAQ software, except that the SCXI functions are not included in the  
LabWindows/CVI software for Sun.  
Using LabVIEW or LabWindows software will greatly reduce the development time for your  
data acquisition and control application.  
NI-DAQ Driver Software  
The NI-DAQ driver software is included at no charge with all National Instruments DAQ  
hardware. NI-DAQ is not packaged with SCXI or accessory products. NI-DAQ has an  
extensive library of functions that you can call from your application programming environment.  
These functions include routines for analog input (A/D conversion), buffered data acquisition  
(high-speed A/D conversion), analog output (D/A conversion), waveform generation, digital I/O,  
counter/timer operations, SCXI, RTSI, self-calibration, messaging, and acquiring data to  
extended memory.  
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Chapter 1  
Introduction  
NI-DAQ also internally addresses many of the complex issues between the computer and the  
DAQ hardware such as programming interrupts and DMA controllers. NI-DAQ maintains a  
consistent software interface among its different versions so that you can change platforms with  
minimal modifications to your code. Figure 1-1 illustrates the relationship between NI-DAQ and  
LabVIEW and LabWindows. You can see that the data acquisition parts of LabVIEW and  
LabWindows are functionally equivalent to the NI-DAQ software.  
Conventional  
Programming  
LabWindows  
(PC or  
Sun SPARCstation)  
LabVIEW  
(PC, Macintosh, or  
Sun SPARCstation)  
Environment  
(PC, Macintosh, or  
Sun SPARCstation)  
NI-DAQ  
Driver Software  
Personal  
DAQ or  
SCXI Hardware  
Computer  
or  
Workstation  
Figure 1-1. The Relationship between the Programming Environment,  
NI-DAQ, and Your Hardware  
The National Instruments PC, AT, MC, EISA, DAQCard, and DAQPad Series DAQ hardware is  
packaged with NI-DAQ software for PC compatibles. NI-DAQ software for PC compatibles  
comes with language interfaces for Professional BASIC, Turbo Pascal, Turbo C, Turbo C++,  
Borland C++, and Microsoft C for DOS; and Visual Basic, Turbo Pascal, Microsoft C with SDK,  
and Borland C++ for Windows. You can use your AT-MIO-16, together with other PC, AT,  
MC, EISA, DAQCard, and DAQPad Series DAQ and SCXI hardware, with NI-DAQ software  
for PC compatibles.  
The National Instruments NB Series DAQ boards are packaged with NI-DAQ software for  
Macintosh. NI-DAQ software for Macintosh comes with language interfaces for MPW C,  
THINK C, Pascal, and Microsoft QuickBASIC. Any language that uses Device Manager  
Toolbox calls can access NI-DAQ software for Macintosh. You can use NB Series DAQ boards  
and SCXI hardware with NI-DAQ software for Macintosh.  
The National Instruments SB Series DAQ boards are packaged with NI-DAQ software for Sun,  
which comes with a language interface for ANSI C.  
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Introduction  
Chapter 1  
Register-Level Programming  
There are no register-level programming concerns for the SC-2040. When using the SC-2040,  
only the MIO-16E Series board needs to be programmed. Refer to your MIO-16E board manual  
for further information on register-level programming.  
Optional Equipment  
Contact National Instruments to order the following optional equipment:  
•
•
•
CB-50 I/O connector (50-screw terminals) with 0.5 or 1.0 m cable  
Single or double height rack-mount kit with acrylic plastic cover  
Single or double height rack-mount kit with metal wraparound cover  
Unpacking  
Your SC-2040 board is shipped in an antistatic package to prevent electrostatic damage to the  
board. Electrostatic discharge can damage several components on the board. To avoid such  
damage in handling the board, take the following precautions:  
•
•
•
Ground yourself via a grounding strap or by holding a grounded chassis such as a computer  
chassis.  
Touch the antistatic package to a metal part of your computer chassis before removing the  
board from the package.  
Remove the board from the package and inspect the board for loose components or any other  
sign of damage. Notify National Instruments if the board appears damaged in any way.  
Do not install a damaged board into your computer.  
•
Never touch the exposed pins of connectors.  
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Chapter 2  
Configuration and Installation  
This chapter describes the configuration and installation of your SC-2040. The topics discussed  
are switch and jumper configuration, connection of the SC-2040 to the MIO-16E, and the power-  
on sequence for your SC-2040 configuration.  
Board Configuration  
The SC-2040 has 10 jumpers, eight DIP switches, and one slide switch that you use to configure  
the board. These switches and jumpers are shown in Figure 2-1.  
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Configuration and Installation  
Chapter 2  
Figure 2-1. SC-2040 Parts Locator Diagram  
SC-2040 User Manual  
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Chapter 2  
Configuration and Installation  
The SC-2040 has one switch that controls whether the board is powered from an external supply  
or from the MIO-16E board. Furthermore, two jumpers control how the board is shielded and  
grounded. Additionally, there are eight sets of switches and jumpers that configure the gain  
settings and input modes of the eight SC-2040 channels.  
Table 2-1. Power Supply Selection  
Switch  
Description  
Configuration  
INT position—Use this setting  
to configure the SC-2040 to  
draw power through the  
MIO-16E board. (factory  
setting)  
SW1  
INT  
EXT  
SW1  
J13  
A. Internal  
Power  
EXT position—Use this  
setting to draw +5 V power  
from an external supply  
connected to connector J13.  
SW1  
INT  
EXT  
B. External  
Power  
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Configuration and Installation  
Chapter 2  
Table 2-2. Shield Selection  
Jumper  
Description  
Configuration  
SHLD OFF position—Place  
the jumper in this position to  
keep the SC-2040 analog  
ground isolated from the metal  
standoffs in the corners of the  
board (factory setting).  
W1  
W1  
SHLD OFF  
SHLD ON  
W1  
SHLD ON position—Place  
the jumper in this position to  
connect the SC-2040 analog  
ground to the metal standoffs  
or to a rack-mount kit, which  
may provide shielding for the  
SC-2040.  
SHLD OFF  
SHLD ON  
Table 2-3. DAQ Board Ground Isolation Selection  
Jumper  
Description  
Configuration  
AIGND-AIGND position—  
Use this setting if you are  
using a MIO-16E DAQ board.  
Place the jumper in this  
position to keep the SC-2040  
digital ground and analog  
grounds isolated (factory  
setting).  
W10  
W10  
DGND  
AIGND  
AIGND  
W10  
AIGND-DGND position—  
Place the jumper in this  
position to connect the  
SC-2040 analog ground to  
digital ground.  
AIGND  
DGND  
AIGND  
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Chapter 2  
Configuration and Installation  
Table 2-4. Channel Gain Selection  
Switch  
Description  
Configuration  
A B C D  
Unity gain position—For  
unity gain (gain = 1), open all  
the switches by pushing down  
the OFF end of the switches.  
(factory setting)  
U2  
1
2
3
4
U6  
U9  
U14  
U17  
U21  
U24  
U28  
OFF  
The unity gain position has  
the number side up.  
Gain Table  
Other gains—Refer to  
Supplementary Configuration  
Information, later in the  
chapter, and the gain table on  
the board itself.  
Table 2-5. Channel Input Mode  
Switch  
Description  
Configuration  
A-B position—Use this  
A
B
C
W2  
W3  
setting for connecting ground-  
referenced signals to the  
SC-2040 (factory setting).  
W2  
W4  
W5  
W6  
W7  
W8  
W9  
A
B
C
B-C position—Use this setting  
for connecting floating (non-  
ground referenced) sources.  
A 100 kΩ resistor is  
connected from the negative  
channel input to the SC-2040  
analog ground.  
W2  
The W3–W9 jumper  
positions are the same  
as on W2.  
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Configuration and Installation  
Chapter 2  
Supplementary Configuration Information  
Power Supply Selection  
Set switch SW1 to the INT position to connect the SC-2040 power converter to the +5 V lines on  
the MIO-16E board. Set switch SW1 to the EXT position to draw power from an external +5 V  
power supply connected to J13.  
The MIO-16E is fused to provide 5 W of power (at +5 V and 1 A). The SC-2040 consumes  
nearly all of this available power. Therefore, if you have other DAQ accessories that you would  
like to power from the MIO, you should switch the SC-2040 to external power and provide an  
external +5 V power source. In external power mode, the SC-2040 is fuse limited to 1 A at  
+5 V.  
Shield Selection  
If you are using a rack-mount kit, shield the SC-2040 from unwanted noise by connecting the  
analog ground on the board to the metal chassis of the rack using jumper W1. When you set W1  
to the SHLD ON position, the jumper connects the analog ground to the metal standoffs used to  
mount the board in a rack. In the SHLD OFF position, the SC-2040 analog ground is isolated  
from the metal standoffs.  
DAQ Board Ground Isolation Selection  
You can use jumper W10 to connect the SC-2040 digital and analog grounds. If you are using a  
MIO-16E board, you must isolate the grounds by leaving the jumper in its default position.  
Gain Selection  
The gain selection switches can select gains of 1, 10, 100, 200, 300, 500, 600, 700, and 800 for  
each channel, as shown in Table 2-6.  
Table 2-6. Gain Switches for Each Channel  
Channel  
Close Switches  
0
1
2
3
4
5
6
7
U2  
U6  
U9  
U14  
U17  
U21  
U24  
U28  
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Chapter 2  
Configuration and Installation  
To close a switch, push down the number side. Closing switch A selects a gain of 500. Closing  
switch B selects a gain of 200. Closing switch C selects a gain of 100. Closing switch D selects  
a gain of 10. Opening all the switches selects a gain of 1. You can select other gains by closing  
more than one switch, as shown in Table 2-7.  
Table 2-7. Switch Settings for Gain Selection  
Desired Gain  
Close Switches  
1
10  
None  
D
C
100  
200  
300  
500  
600  
700  
800  
B
B and C  
A
A and C  
A and B  
A, B, and C  
Input Mode Selection  
Jumpers W2 through W9 select the input mode for each channel on the SC-2040. Position A-B  
leaves the negative input of the instrumentation amplifier connected only to the front connector.  
This is the factory-default setting. Position B-C connects the negative input of the  
instrumentation amplifier to the board analog ground through a 100 kΩ resistor. This setting is  
useful for keeping floating, or nonground-referenced, sources from saturating the instrumentation  
amplifier. Table 2-8 shows the input mode jumper and channel selections.  
Table 2-8. Input Mode Selection Jumpers  
Channel  
Use Jumper  
0
1
2
3
4
5
6
7
W2  
W3  
W4  
W5  
W6  
W7  
W8  
W9  
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Configuration and Installation  
Chapter 2  
Installation  
Note: You must turn off power to the PC, and to the SC-2040 board if the board is externally  
powered, before installing the board or making any connections to it.  
To install the SC-2040, connect the 68-pin ribbon from the MIO-16E I/O connector to connector  
J12 on the SC-2040. The SC-2040 can be mounted in a rack-mount chassis using the mounting  
holes (indicated with an arrow on the board) in the four corners of the SC-2040 board.  
The SC-2040 is installed. You are now ready to install and configure your software.  
If you are using NI-DAQ, refer to your NI-DAQ manual. The software installation and  
configuration instructions are in Chapter 1, Introduction to NI-DAQ. Find the installation and  
system configuration section for your operating system and follow the instructions given there.  
If you are using LabVIEW, the software installation instructions are in your LabVIEW release  
notes. After you have installed LabVIEW, refer to the Configuring LabVIEW section of  
Chapter 1 of your LabVIEW user manual for software configuration instructions.  
If you are using LabWindows, the software installation instructions are in Part 1, Introduction to  
LabWindows, of the Getting Started with LabWindows manual. After you have installed  
LabWindows, refer to Chapter 1, Configuring LabWindows, of the LabWindows User Manual  
for software configuration instructions.  
Power-on Sequence  
If the SC-2040 is powered by an external power source, you must turn on power to the SC-2040  
before turning on the computer. Similarly, you must turn off power to the SC-2040 after turning  
off the computer. The red LED labeled DS1 indicates when power is applied to the board.  
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Chapter 3  
Signal Connections  
This chapter describes the signal connections to the SC-2040 board, and cable wiring.  
I/O Connector Pin Description  
Warning: Connections that exceed any of the maximum ratings of input or output signals on  
the MIO-16 can result in damage to the MIO-16 board and to the personal  
computer. This includes connecting any power signals to ground and vice versa.  
National Instruments is not liable for any damages resulting from any such signal  
connections.  
Corresponding signals on connectors J11 and J12 are connected together through the SC-2040.  
Connector J12 carries the signals to and from the MIO-16E board. Use connector J11 to access  
these signals. You can use this connector to monitor these signals, using a National Instruments  
CB-50, for example, or you can use this connector to connect to other DAQ accessories.  
Figure 3-1 shows these connectors.  
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Signal Connections  
Chapter 3  
1
3
5
7
9
2
4
68  
67  
66  
65  
34  
33  
32  
31  
6
8
64  
63  
30  
29  
28  
10  
62  
11 12  
13 14  
15 16  
17 18  
19 20  
21 22  
23 24  
25 26  
27 28  
29 30  
31 32  
33 34  
35 36  
37 38  
39 40  
41 42  
43 44  
45 46  
47 48  
49 50  
27  
26  
61  
60  
59  
58  
25  
24  
57  
56  
23  
22  
21  
20  
19  
18  
55  
54  
53  
52  
51  
50  
49  
48  
47  
46  
45  
17  
16  
15  
14  
13  
12  
11  
10  
9
44  
43  
8
7
6
5
4
3
2
42  
41  
40  
39  
38  
37  
36  
35  
1
B. I/O Connector J12  
A. Breakout Connector J11  
Figure 3-1. SC-2040 I/O Connectors J11 and J12  
Table 3-1 lists the pin assignments for the breakout connector J11 and the I/O connector J12 on  
the SC-2040 and the corresponding and MIO-16E Series signal names.  
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Chapter 3  
Signal Connections  
Table 3-1. Pin Assignments for Connectors J11 and J12  
Breakout Connector J11  
Pin Numbers  
SC-2040  
Signal Names  
MIO-16E Series  
Signal Names  
I/O Connector J12  
1
Pin Numbers  
1, 2  
3
4
5
6
7
8
9
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
21  
22  
23  
24, 33  
AIGND  
ACH0  
AIGND  
ACH1  
AIGND  
ACH2  
AIGND  
ACH3  
AIGND  
ACH4  
AIGND  
ACH5  
AIGND  
ACH6  
AIGND  
ACH7  
AIGND  
NC  
AIGND  
ACH0  
ACH8  
ACH1  
ACH9  
ACH2  
ACH10  
ACH3  
ACH11  
ACH4  
ACH12  
ACH5  
ACH13  
ACH6  
ACH14  
ACH7  
ACH15  
AISENSE  
DAC0OUT  
DAC1OUT  
EXTREF  
AOGND  
DGND  
24, 27, 29, 32, 56, 59, 64, 67  
68  
34  
33  
66  
65  
31  
30  
63  
28  
61  
60  
26  
25  
58  
57  
23  
62  
22  
21  
20  
NC  
NC  
NC  
NC  
54, 55  
DGND  
4, 7, 9, 12, 13, 15, 18, 35, 36, 39,  
44, 50, 53  
52  
19  
17  
51  
49  
16  
47  
48  
8, 14  
46  
45  
11  
10  
43  
42  
41  
40  
6
25  
26  
27  
28  
29  
30  
31  
32  
34, 35  
36  
37  
38  
39  
40  
41  
42  
43  
44  
45  
46  
47  
48  
49  
50  
NC  
NC  
NC  
NC  
NC  
NC  
NC  
NC  
+5V  
NC  
NC  
NC  
NC  
TRIG  
NC  
NC  
NC  
NC  
NC  
DIO0  
DIO4  
DIO1  
DIO5  
DIO2  
DIO6  
DIO3  
DIO7  
+5V  
SCANCLK  
EXTSTROBE*  
PFI0/TRIG1  
PFI1/TRIG2  
PFI2/CONVERT*  
PFI3/GPCTR1_SOURCE  
PFI4/GPCTR1_GATE  
GPCTR1_OUT  
PFI5/UPDATE*  
PFI6/WFTRIG  
PFI7/STARTSCAN  
PFI8/GPCTR0_SOURCE  
PFI9/GPCTR0_GATE  
GPCTR0_OUT  
FREQ_OUT  
5
TRACK*/HOLD  
38  
37  
3
2
1
NC  
NC  
NC  
NC  
1
All signals labeled NC are unused by the SC-2040.  
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Signal Connections  
Chapter 3  
Signal Connection Description  
Table 3-2. Input Connectors Signal Summary  
Connector  
Signal Name  
Description  
J5  
AIGND  
Analog Input Ground—These inputs provide a bias current return point  
for AC-coupled signals.  
J1, J2, J3, J4,  
J6, J7, J8, J9  
CH+<0..7>  
CH-<0..7>  
DGND  
Positive Inputs—These inputs are the positive signal inputs for  
channels 0 through 7.  
J1, J2, J3, J4,  
J6, J7, J8, J9  
Negative Inputs—These inputs are the negative signal inputs for  
channels 0 through 7.  
J10, J13  
Digital Ground—These inputs provide the reference for all digital signals  
and the reference for the +5 V power source.  
J10  
TRIG  
Trigger—This input, which is connected directly to the PFI2 pin on  
connectors J11 and J12, is a trigger input for the MIO-16E. A low-to-  
high transition on TRIG alerts the MIO-16E to place the SC-2040 into  
hold mode and start acquiring data.  
J13  
+5 V  
+5 VDC Source—When external power is selected, this input provides  
DC power for the SC-2040 from an external +5 V. The SC-2040 fuses  
the input to 1 A of the +5 V supply.  
Table 3-3. Output Connectors (J11 and J12) Signal Summary  
J11 Pin  
(50-pin)  
J12 Pin  
(68-pin)  
Signal Name  
Description  
1, 2, 4, 6, 8,  
10, 12, 14, 16, 29, 31, 32, 34,  
18  
23, 24, 26, 27,  
AIGND  
Analog Input Ground—These pins establish the  
reference point for the SC-2040 outputs (ACH<0..7>).  
They are also connected directly to the AIGND input  
connector J5 for use with AC-coupled signals.  
56, 58, 59, 61,  
63, 64, 66, 67  
3, 5, 7, 9, 11,  
13, 15, 17  
68, 33, 65, 30,  
28, 60, 25, 57  
ACH<0..7>  
DGND  
Analog Channels 0 through 7—These pins carry the  
outputs of the SC-2040 eight channels to the DAQ  
board. They are referenced to AIGND.  
24, 33  
34, 35  
40  
4, 7, 9, 12, 13,  
15, 18, 35, 36,  
39, 44, 50, 53  
Digital Ground—These pins are the reference for the  
+5 V power source and for the digital signals used by  
the SC-2040: TRIG (PFI2) and TRACK*/HOLD  
(PFI7/STARTSCAN).  
8, 14  
+5 V  
+5 VDC Source—When internal power is selected,  
these pins provide DC power for the SC-2040 from  
the MIO-16E board. The MIO-16E pins are fused to  
1 A of +5 V supply.  
43  
TRIG (PFI2)  
Trigger—This pin, which is connected directly to the  
TRIG input on screw terminal connector J10, is a  
trigger input to the MIO-16E PFI2 line. A low-to-  
high transition on PFI2 alerts the MIO-16E to place  
the SC-2040 into hold mode and start acquiring data.  
(continues)  
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Chapter 3  
Signal Connections  
Table 3-3. Output Connectors (J11 and J12) Signal Summary (Continued)  
J11 Pin  
(50-pin)  
J12 Pin  
(68-pin)  
Signal Name  
Description  
46  
38  
TRACK*/HOLD  
Track-or-hold—This pin, used as an output from the  
(PFI7/STARTSCAN) MIO-16E, controls whether the SC-2040 is in hold  
mode or track mode. A high level output from the  
DAQ board places the SC-2040 into hold mode, while  
a low level returns the SC-2040 into track mode. With  
an MIO-16E attached, pin 46 on J11 should be used  
for monitoring purposes only.  
others  
others  
compatibility  
The remaining pins provide 50 pin compatibility with  
the 68 pin MIO-16E. They can be monitored from  
connector J11. Refer to Figure 3-1 for pin locations  
and to Chapter 3, Signal Connections, in your MIO-  
16E manual for pin descriptions.  
The signals from the SC-2040 screw terminal connectors are connected to the MIO-16E via J12  
as shown in Figure 3-2. Observe that the PFI7/STARTSCAN signal returns from the MIO-16E  
as a level-sensitive track-and-hold signal to the SC-2040. Notice also that AISENSE is  
disconnected.  
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Signal Connections  
Chapter 3  
SC-2040  
Input Signals  
Signals Sent  
to MIO-16  
J5  
J1  
AIGND  
AIGND  
AISENSE  
CH0+  
CH0-  
T/H  
T/H  
ACH0  
CH1+  
ACH1  
J2  
CH1-  
.
.
.
.
.
.
.
.
.
.
.
.
.
CH7  
.
T/H  
ACH7  
J9  
CH7  
TRIG  
PFI2/  
J10  
STARTSCAN  
DGND  
PFI7  
Track*/Hold  
DGND  
SC-2040  
J11 and J12  
Screw Terminals  
Connectors on SC-2040  
Figure 3-2. SC-2040 Signal Routing  
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Chapter 3  
Signal Connections  
Analog Signal Inputs  
Connect the differential signals to be measured to the screw terminal connectors J1 through J4  
and J5 through J9.  
DC-Coupled Inputs  
Note: If all your inputs are DC-coupled, leave connector J5 disconnected.  
All eight channels have fully differential inputs, so the signals you are measuring should be  
ground referenced. If they are not, set jumpers W2 through W9 of the nonreferenced channels to  
position B-C to create a DC path for the input bias currents. If you do not do this, the bias  
currents of the instrumentation amplifiers of the nonreferenced channels produce stray  
capacitances, resulting in uncontrollable drift and possible saturation.  
Figure 3-3 illustrates how to connect a ground-referenced signal.  
CH+  
IN+  
Vin  
CH-  
IN-  
A
B
C
100 kΩ  
SC-2040  
A
Figure 3-3. Ground-Referenced Signal Connection  
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Signal Connections  
Chapter 3  
Figure 3-4 illustrates how to connect a floating signal.  
CH+  
IN+  
IN-  
Vin  
CH-  
A
B
C
100 kΩ  
SC-2040  
A
Figure 3-4. Floating Signal Connection  
AC-Coupled Signals  
Note: For AC-coupled signals, you must reference the analog ground of your  
instrumentation to the DAQ board. The SC-2040 connector J5 provides the analog  
reference, connecting directly to the MIO-16E board as shown in Figure 3-2.  
For AC-coupled signals, set jumpers W2 through W9 to position B-C with an external resistor  
from the positive input channel connected to its negative ground. Doing this creates the DC path  
for the positive input bias current. Typical resistor values range from 100 kΩ to 10 MΩ. This  
solution, although necessary in this case, lowers the input impedance of the channel and  
introduces an additional offset voltage proportional to the product of the input bias current and  
the resistor value used. The inputs of the SC-2040 have a typical bias current of about ±100 pA.  
When you use a 1 MΩ resistor, the result is ±100 µV of offset, which is insignificant in most  
applications. However, if you use larger valued bias resistors, significant input offset may result.  
Lower valued bias resistors will increase loading of the source, possibly resulting in gain error.  
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Chapter 3  
Signal Connections  
Figures 3-5 through 3-7 illustrate how to connect AC-coupled signals.  
CH+  
IN+  
Vin  
CH-  
IN-  
A
B
C
100 kΩ  
SC-2040  
A
Figure 3-5. Ground-Referenced AC-Coupled Signal Connection  
CH+  
IN+  
Vin  
CH-  
IN-  
A
B
C
100 kΩ  
SC-2040  
Analog  
GND  
A
A
Figure 3-6. Ground-Offset AC-Coupled Signal Connection  
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Signal Connections  
Chapter 3  
CH+  
CH-  
IN+  
IN-  
Vin  
A
B
C
100 kΩ  
SC-2040  
A
Figure 3-7. Floating AC-Coupled Signal Connection  
Analog Input Ranges  
Warning: Exceeding the differential and common-mode input ranges results in distorted  
input signals. Exceeding the maximum input voltage rating can result in damage  
to the SC-2040 board, and the DAQ board. National Instruments is NOT liable for  
any damages resulting from such signal connections.  
The SC-2040 instrumentation amplifiers can reject any voltage within their common-mode input  
range caused by ground-potential differences between the signal source and the board. In  
addition, the amplifiers can reject common-mode noise pickup in the leads connecting the signal  
sources to the SC-2040 board. However, you should be careful to minimize noise pickup. The  
common-mode rejection of the instrumentation amplifiers decreases significantly at high  
frequencies. The amplifiers do not reject normal-mode noise.  
The common-mode input range of the SC-2040 instrumentation amplifiers is defined as the  
magnitude of the greatest common-mode signal that can be rejected. Thus the common-mode  
input range for the SC-2040 depends on the gain and size of the differential input signal:  
(Vdiff = V+ - V-in).  
in  
The exact formula for the permissible common-mode input range is as follows:  
G Vdiff  
Vcm-allowed = ± (12 V -  
).  
2
Thus, with a differential voltage of 10 V and a gain of G = 1, the maximum possible common-  
mode voltage would be ±7 V. The same range would apply for a differential input of 100 mV  
and a gain of 100. The range increases to ±12 V for zero differential input voltage. The actual  
common-mode voltage available at the input is measured with respect to the SC-2040 ground,  
and can be calculated by the following formula:  
V+ − V−  
in  
in  
(
)
Vcm-actual  
=
.
2
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Chapter 3  
Signal Connections  
where V+ is the signal at the positive input (IN0+ through IN7+), and V-in is the signal at the  
in  
corresponding negative input (IN0- through IN7-). Both V+ and V-in are measured with respect  
in  
to the SC-2040 chassis ground.  
Digital Signal Inputs  
If you are using an external trigger, connect the trigger source and the digital reference to screw  
connector J9. This signal should be in the range 0 to +5 V, with switching occurring around  
1.5 V.  
Note: All digital signals on the SC-2040 are referenced to the +5 V power supply. If the  
MIO-16E supplies power, it provides this reference. If an external supply provides  
power, it provides this reference through connector J13.  
A rising edge on the trigger will place the SC-2040 into hold mode, and the SC-2040 will return  
to track mode when the MIO-16E indicates that the data acquisition is complete.  
Although the TRIG signal is a digital signal, it is still susceptible to noise, particularly at its  
transitions. This noise can cause the SC-2040 to enter hold mode on the wrong edge. Two  
possible sources of noise are interference and reflection. The best way to reduce noise  
corruption is to minimize the distance that the signal must travel. Furthermore, you can  
minimize interference by properly shielding the incoming trigger signal. You can minimize  
reflection by ensuring that the impedance of the source of the trigger signal matches the  
impedance of the cable used to transmit the signal; inserting a small resistor (about 50 Ω) in  
series with the signal source will minimize reflection.  
Monitoring Signal Outputs  
You can use connector J11 to monitor the signals being sent to and from the MIO-16E board.  
Figure 4-3 shows a sampled analog signal as the SC-2040 channel output.  
You can also monitor the state of the SC-2040 through line PFI7/STARTSCAN. A high level on  
PFI7/STARTSCAN indicates the SC-2040 is in hold mode, while a low level indicates that the  
SC-2040 is in track mode.  
Other Connection Considerations  
Refer to the sections titled Analog Input Signal Connections and Cabling and Field Wiring in  
Chapter 3 of your MIO-16E board user manual for additional signal connection information.  
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Chapter 4  
Theory of Operation  
This chapter contains a functional overview of the SC-2040 board and explains the operation of  
each functional unit making up the SC-2040.  
Functional Overview  
The SC-2040 consists of eight channels, each one comprising an instrumentation amplifier with  
DIP switch-programmable gains of 1, 10, 100, 200, 300, 500, 600, 700, or 800, and a track-and-  
hold amplifier. The analog inputs are overvoltage protected. The DAQ board or a user-supplied  
external trigger switches the SC-2040 between hold mode and track mode as desired. All eight  
channels are simultaneously placed in hold mode.  
The block diagram in Figure 4-1 illustrates the key functional components of the SC-2040.  
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Theory of Operation  
Chapter 4  
68-Pin I/O Connector  
50-Pin Breakout Connector  
•
•
•
•
•
•
•
•
Input  
Protection  
Input  
Protection  
•
•
•
•
•
•
Figure 4-1. SC-2040 Block Diagram  
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Chapter 4  
Theory of Operation  
Analog Circuitry  
The analog input circuitry consists of eight channels with DIP-switch-programmable  
instrumentation amplifiers followed by buffered track-and-hold amplifiers. In addition, you can  
include the voltage-regulation circuitry and input protection in the analog section. Each block is  
described in the following paragraphs.  
Input Protection  
The first block an incoming analog signal encounters is the input protection. Each input terminal  
is protected against input voltages up to ±15 V powered off and ±30 V powered on. The input  
protection consists of a 1 kΩ resistor in series with each input line followed by low-leakage  
diodes to the supply rails (±15 V).  
Amplification  
Next in the signal path are the instrumentation amplifiers, which fulfill two purposes on the  
SC-2040 board. First, the instrumentation amplifiers convert differential input signals into  
single-ended signals referred to the SC-2040 analog ground for input common-mode signal  
rejection. With this conversion, the SC-2040 can extract the analog input signals from common-  
mode noise voltages before the DAQ board samples and converts the signals. Second, the  
instrumentation amplifiers amplify input signals, resulting in an increase in measurement  
resolution and accuracy. Furthermore, the amplifiers exhibit low bias currents and good  
bandwidth, even at high gains.  
You can select gains for each channel independently with separate DIP switches. Gains are 1,  
10, 100, 200, and 500, although gains of 300, 600, 700, and 800 are available with reduced  
accuracy. See Appendix A, Specifications, for details on the performance of the instrumentation  
amplifiers.  
Track-and-Hold (T/H) Circuitry  
The track-and-hold amplifiers operate as simple buffers when in track mode, but freeze their  
outputs when placed into hold mode. Because all of the track-and-hold amplifiers in each  
SC-2040 board enter hold mode at the same time, they implement simultaneous sampling of all  
channels. Simultaneous sampling is useful for preserving phase relationships between channels.  
The track-and-hold amplifiers are subject to various imperfections, which are listed in  
Appendix A, Specifications. The most relevant of these performance specifications are the track-  
mode acquisition time and the hold-mode settling time, as these parameters affect how the DAQ  
board acquires the data, most noticeably through the sampling rate.  
The hold-mode settling time refers to how long it takes the T/H amplifiers to settle a stable value.  
Thus, the hold-mode settling time affects how long the DAQ board must wait before attempting  
to acquire data. The track-mode acquisition time refers to how long it takes the T/H amplifiers to  
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Theory of Operation  
Chapter 4  
find the inputs again after having been in hold mode. Therefore, this delay indicates how long  
the SC-2040 must remain in track mode before it is ready to re-enter hold mode. Returning the  
SC-2040 to hold mode before the track-mode acquisition delay has elapsed will cause the  
SC-2040 to "hold" erroneously. Figure 4-2 illustrates these timing concerns. Typical hold mode  
settling times and track acquisition times for 12-bit and 16-bit accuracies are given in  
Appendix A, Specifications.  
differential channel  
input  
T/H output  
hold setting time  
hold setting  
time  
track acquisition  
time  
track*/hold signal  
(PF17)  
track  
track  
hold  
hold  
Figure 4-2. T/H Amplifier Hold Settling Time and Track Acquisition Time  
Triggering from the DAQ Board  
This section applies to you only if you are triggering the SC-2040 from the MIO-16E board.  
Note: No signal should be connected to connector J10 for MIO-16E triggering.  
You can place the SC-2040 into hold mode on command using the MIO-16E DAQ board. You  
must either program the MIO-16E board for this purpose or use the NI-DAQ software included  
with your MIO board. After placing the SC-2040 into hold mode, the MIO-16E board performs  
data acquisition and conversion. Once this process is complete, the MIO-16E board releases the  
SC-2040 into track mode.  
The MIO-16E board uses line PFI7/STARTSCAN to indicate to the SC-2040 whether it should  
track the input signals or hold them at a constant level. A logic zero (low level) on  
PFI7/STARTSCAN indicates track mode, while a logic one (high level) indicates hold mode, as  
indicated in Figure 4-3.  
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Chapter 4  
Theory of Operation  
Differential Channel Input  
PFI7 (track*/hold)  
hold  
hold track  
SC-2040 Channel Output  
t
t
DAQ Conversion  
(DAQ board is scanning)  
DAQ Conversion  
Figure 4-3. MIO-16E Controlled Triggering  
External Triggering  
This section applies to you only if you are triggering the board from an external signal  
connected to J10.  
You can connect an external trigger to place the SC-2040 into hold mode on command. A rising  
edge on the external trigger signal places the SC-2040 into hold mode and alerts the MIO-16E  
board to start scanning the SC-2040 outputs. After the MIO-16E board has acquired data from  
all of the channels, it returns the SC-2040 to track mode. The external trigger signal is a digital  
input and must conform to digital logic levels.  
Because the SC-2040 track-and-hold circuitry must re-acquire the input signals at the conclusion  
of each hold mode operation, the external trigger source should not return the SC-2040 to hold  
mode until after the SC-2040 has had time to re-acquire the signals. The acquisition times for  
the SC-2040 at various accuracies are given in Appendix A, Specifications.  
The external trigger is connected directly to signal PFI2 on the DAQ board. A rising edge alerts  
the DAQ board to place the SC-2040 into hold mode. The DAQ board then begins scanning the  
channels. After the scanning process is complete, the board returns the SC-2040 to track mode  
using PFI7/STARTSCAN. Notice that additional rising edges from the external trigger are  
ignored while the MIO-16E is scanning. Figure 4-4 illustrates the external triggering process.  
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Theory of Operation  
Chapter 4  
Differential Channel Input  
PFI2 (external trigger)  
PFI7 (track*/hold)  
track  
hold  
hold  
track  
SC-2040 Channel Output  
t
t
DAQ Conversion  
DAQ Conversion  
(DAQ board is scanning)  
Figure 4-4. External Triggering  
Output Connection  
The output of every channel is connected to the 68-pin rear signal connector and the 50-pin  
supplemental I/O connector. The 68-pin connector carries signals to and from the DAQ board,  
and also provides +5 V power if selected by the power switch. The corresponding pins of the  
50-pin connector are tied to those of the 68-pin connector so that you can monitor these signals  
on the 50-pin connector. The pin connections of these connectors are given in Chapter 3, Signal  
Connections.  
Power Supply  
The SC-2040 contains an onboard power switch to either power the SC-2040 from the MIO-16E  
board or to draw power from an external +5 V supply. From the +5 V power, an onboard  
DC-to-DC converter generates a ±15 V source, which is used to power the analog circuitry. A  
red LED indicates that the board is receiving power.  
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Chapter 5  
Calibration Procedures  
This chapter discusses the calibration procedures for the SC-2040 board.  
Note: In many applications, the SC-2040 factory-hardware calibration is sufficient to meet  
accuracy requirements, and no further calibration, either hardware or software, is  
needed.  
Although hardware calibration is discussed in greater detail than software calibration, software  
calibration is the preferred choice for the following reasons:  
•
The calibration adjustments on the SC-2040 are inaccessible under most normal operating  
circumstances.  
•
With software calibration, the board is calibrated in the exact environment in which it will be  
operating. Software calibration compensates for system-introduced, in addition to board-  
introduced, errors. You can perform software calibration fairly frequently, which helps  
reduce drift effects.  
Because board-introduced errors are minimal with the SC-2040, the use of software rather than  
hardware calibration does not significantly reduce dynamic range. The main drawback of  
software calibration is reduced throughput due to the increased processing time.  
Software Calibration  
Software calibration is very simple. Depending on your accuracy requirements, you may want to  
perform only offset adjustment; offset and gain adjustments; or offset, gain, and linearity  
adjustments.  
Offset Adjustment  
Offset adjustment requires you to apply an input signal of zero to the channel to be calibrated.  
Zero input can mean shorting the board inputs to zero, or it can mean applying zero excitation to  
the transducer being used. In the former case, you can remove only board and DAQ board  
offset; in the latter case, transducer offset is removed as well. In either case, measurements are  
taken with the zero input signal. Average these measurements to reduce uncertainty. This  
average represents the offset. Next, subtract the offset from all subsequent measurements.  
Notice that offset changes with gain; thus, during calibration, set the channel to the gain at which  
the subsequent measurements will be taken.  
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Calibration Procedures  
Chapter 5  
Gain Adjustment  
Gain adjustment requires you to apply two different input signals. One of the two points is  
typically zero, because zero is easy to generate with a high degree of accuracy. The other should  
be near full scale, either a DC-voltage from a precision calibrator or a voltage generated by  
applying a known excitation to the transducer being used. Of course, you should generate both  
signals—zero and full scale—from the same source.  
Take measurements on both signals and compute separate averages. Then combine the averages  
with the known input signals to generate linear correction factors for all subsequent  
measurements. Specifically, if the input X yields measurement x, and the input Y yields  
measurement y, then you should process measurement z as shown in the following equation to  
yield the corrected measurement Z:  
(Y − X)(z − x)  
Z = X +  
.
(y − x)  
Linearity Adjustment  
The SC-2040 seldom needs linearity adjustment because its linearity is quite good, especially at  
low gains. Linearity error is often caused by the nonlinearity of the DAQ board you use. If  
necessary, the method described previously for correcting gain and offset error may be extended  
to include linearity by taking more points along the transfer function and processing the  
subsequently acquired data according to a polynomial fit of the calibration points.  
Alternatively, and preferably for DAQ boards with no more than 12 bits of resolution, you can  
determine the nonlinearity of the system on a code-by-code basis, and you can subtract the error  
of each code from any measurement that returns that value. This method has the advantage of  
correcting differential as well as integral linearity errors. However, this method may be time-  
consuming. If time permits, you may determine the nonlinearity of your system on a code-by-  
code basis with even higher resolution DAQ boards. Describing methods of measuring system  
nonlinearity is beyond the scope of this manual. If linearity correction becomes necessary, refer  
to your DAQ board user manual.  
Hardware Calibration  
There are two potentiometers (pots) to adjust for each channel. These are set at the factory and  
should not need to be readjusted for most applications. The pots adjust input offset voltage and  
output offset voltage for each of the eight channels. Gain error and linearity are not adjustable.  
For detailed specifications of offset, gain, and linearity error, see Appendix A, Specifications.  
Input offset is any error voltage that appears to be added to the input signal; that is, its effect is  
multiplied by the gain of the instrumentation amplifier. Output offset is any error voltage that  
appears to be added to the output signal; that is, its effect is independent of the gain of the  
instrumentation amplifier. At a fixed gain, these errors are indistinguishable; thus, it is necessary  
to switch between gains to properly calibrate the SC-2040.  
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Chapter 5  
Calibration Procedures  
Your accuracy needs determine how carefully the offsets need to be calibrated. A typical  
requirement might be for total offset referred to output to be less than half of an LSB of the DAQ  
board being used. For example, a 12-bit, 20 V system has a resolution of 20 V/212 = 4.88 mV.  
Calibration to under 2 mV would thus be sufficient for most applications. The SC-2040 is  
factory calibrated to have total offset referred to output of less than 2 mV at low gains.  
Table 5-1 shows which pots to adjust for each type of offset for each channel and which DIP  
switch selects the gain for each channel. Refer to the parts locator diagram in Chapter 2,  
Configuration and Installation, to determine the location of each component.  
Table 5-1. Calibration Component Identification  
Channel  
Output Offset Adjust  
Input Offset Adjust  
Gain DIP Switch  
0
1
2
3
4
5
6
7
R1  
R7  
R4  
U2  
U6  
U9  
U14  
U17  
U21  
U24  
U28  
R11  
R16  
R22  
R29  
R35  
R41  
R48  
R13  
R18  
R25  
R32  
R37  
R45  
A complicating factor in the calibration of the board is that the output offset is not the same in  
track mode as in hold mode. This difference is because of a phenomenon known as hold step, in  
which a small amount of charge is transferred to the track-and-hold amplifier hold capacitor  
during the transition from track mode to hold mode. This charge transfer slightly changes the  
voltage at the output of the track-and-hold amplifier.  
The magnitude of the hold step on the SC-2040 is approximately 5 mV, enough to make it  
necessary to calibrate output offset in hold mode rather than track mode. You may calibrate  
input offset without switching the board to hold mode.  
To calibrate the SC-2040 board, the following steps are required:  
1. If you are using a rack-mount kit, remove the cover to expose the DIO switches and jumpers.  
Connect the board so that the pots and DIP switches are readily accessible.  
2. Short each input of the board to ground.  
At low gains, more alternatives exist to serve as a short circuit, but at a gain of 500, 1 mV  
referred to the output is only 2 µV referred to the input. Thermoelectric effects make it  
difficult to keep a short circuit from generating such voltages. The best solution is to use  
short lengths of heavy copper wire, and to keep the short away from heat sources.  
3. Program the DAQ board to take data in the differential input mode.  
The SC-2040 should switch between track mode and hold mode, with the DAQ board  
sampling occurring while the board is in hold mode.  
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Calibration Procedures  
Chapter 5  
4. Set the DAQ board to a high gain and measure its offset by shorting its input.  
You must subtract this measured offset from all subsequent board measurements to ensure  
accuracy.  
For the offset of the DAQ board not to affect the calibration, you must subtract the offset  
from all board offset measurements. Thus, you must first measure the offset to an accuracy  
better than that to which the board is to be calibrated. Furthermore, setting the DAQ board to  
a high gain (100, for example) makes it possible to resolve offset changes that would be  
indiscernible at lower gains. Because the DAQ board offset will not be independent of gain,  
you should set the gain first, and then measure the offset. To measure the offset, disconnect  
the board from the DAQ board, short circuit the board inputs to ground, and take some data.  
The measured value is the offset. For a reliable value, use software to average a few hundred  
readings. After you have measured and recorded the offset, remove the short circuits and  
reconnect the board.  
5. Measure the output of the first channel with its gain set to one and adjust its output offset pot  
until the output is close to zero.  
At this gain, most of the board offset is due to output offset. The input offset adjustment has  
minimal effect. Set the DAQ board to read the channel. Acquire the data, averaging as in  
step 4. Adjust the output offset pot until the difference between the measured offset and the  
DAQ board offset is close to zero. There is no need to adjust it perfectly because the input  
offset adjustment in the next step might make a slight change in the measured gain-of-one  
offset.  
6. Measure the output of the same channel with its gain set to 500 and adjust its input offset pot  
until the output is close to zero.  
At this gain, the input offset adjustment has the dominant effect. Acquire the data and  
average as before. Adjust the input offset pot until the difference between the measured  
offset and the DAQ board offset is close to zero. Again, it is not necessary to adjust the input  
offset perfectly because there will be a slight interdependence between the two offsets.  
7. Repeat step 5, adjusting the offset as carefully as desired. Then repeat step 6, adjusting the  
offset as carefully as desired. Switch back to a gain of one to ensure that the low-gain offset  
is still calibrated. If necessary, repeat steps 5 and 6 until the offset is calibrated at both gains.  
8. Repeat steps 5 through 7 for the additional channels you want to calibrate. There is no  
calibration interdependence among the channels.  
9. Replace the rack-mount chassis cover, if used.  
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Appendix A  
Specifications  
This appendix lists the specifications for the SC-2040. These are typical at 25° C unless otherwise stated. The  
operating temperature range is 0° to 50° C.  
Analog Input  
Input Characteristics  
Number of channels  
Input signal ranges  
8 differential  
Board Gain  
Board Range  
Max Output Range ±10 V  
(Hardware  
Selectable)  
1
10  
±10 V  
±1 V  
100  
200  
300  
500  
600  
700  
800  
±100 mV  
±50 mV  
±33.3 mV  
±20 mV  
±16.67 mV  
±14.29 mV  
±12.5 mV  
Input coupling  
DC  
Max working voltage  
(signal + common mode)  
Overvoltage protection  
Inputs protected  
Average of 2 inputs should remain within ±7 V of ground  
±30 V powered on, ±15 V powered off  
ACH<0..7>  
Transfer Characteristics  
Offset error  
Pregain error after calibration  
Postgain error after calibration  
±100 µV max  
±2 mV max  
Gain error and nonlinearity  
Gain  
(DIP-switch-  
selectable)  
Max  
Gain Error  
Max  
Gain Tempco  
Max  
Nonlinearity  
1
10  
±0.05%  
±0.1%  
±25 ppm/°C  
±25 ppm/°C  
±45 ppm/°C  
±60 ppm/°C  
±80 ppm/°C  
±100 ppm/°C  
±120 ppm/°C  
±150 ppm/°C  
±200 ppm/°C  
±0.01%  
±0.01%  
±0.02%  
±0.02%  
±0.03%  
±0.04%  
±0.05%  
±0.06%  
±0.07%  
100  
200  
300  
500  
600  
700  
800  
±0.2%  
±0.4%  
-0.3%, ±0.6%  
±1.0%  
-0.2%, ±1.5%  
-0.1%, ±2.0%  
-0.3%, ±3.0%  
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Specifications  
Appendix A  
Amplifier Characteristics  
Input impedance  
Normal powered on  
Input bias current  
Input offset current  
100 GΩ in parallel with 20 pF  
±100 pA, ±10 mA max  
±10 pA  
CMRR  
Gain  
dB (min and typ)  
Gain = 1  
Gain = 10  
Gain ≥ 100  
70 dB min, 90 dB typ  
87 dB min, 104 dB typ  
100 dB min, 110 dB typ  
Output range  
±10 V  
Dynamic Characteristics  
Bandwidth  
Gain  
-3 dB  
Bandwidth  
1
2 MHz  
800 kHz  
500 kHz  
300 kHz  
180 kHz  
120 kHz  
100 kHz  
80 kHz  
10  
100  
200  
300  
500  
600  
700  
800  
70 kHz  
System noise  
Gain  
Filter  
1
10  
100  
200  
300  
500  
600  
700  
800  
175 µVrms  
50 µVrms  
45 µVrms  
40 µVrms  
35 µVrms  
33 µVrms  
30 µVrms  
29 µVrms  
27 µVrms  
Noise spectral density  
Input noise (gain = 1)  
Output noise  
12 nV/√Hz  
85 nV/√Hz  
8 V/µs  
Slew rate  
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Appendix A  
Specifications  
S/H Characteristics  
Measurement  
0.012%  
0.003%  
0.0015% 0.00076%  
Track mode  
acquisition  
time  
7 µs  
10 µs  
50 µs  
1 ms  
Hold mode  
settling time  
1 µs  
1 µs  
1 µs  
2 µs  
Hold step  
-5 mV  
±10 mV/s  
250 ns  
—
—
—
—
—
—
—
—
—
—
—
—
Droop rate  
Aperture time  
Interchannel  
skew  
±50 ns  
Stability  
Recommended warm-up time  
Offset temperature coefficient  
15 min  
±(10 + 150/gain) µV/°C  
Gain temperature coefficient  
Gain  
(DIP-switch-  
selectable)  
Max  
Gain Tempco  
1
10  
±25 ppm/°C  
±25 ppm/°C  
±45 ppm/°C  
±60 ppm/°C  
±80 ppm/°C  
±100 ppm/°C  
±120 ppm/°C  
±150 ppm/°C  
±200 ppm/°C  
100  
200  
300  
500  
600  
700  
800  
Power Requirement  
+5 VDC (±10 %)  
Total power dissipation  
800 mA  
4 W  
Physical  
Dimensions  
I/O connectors  
Input  
1.8 by 7.9 by 4.9 in. (4.6 by 20.1 by 12.4 cm)  
20-screw terminals  
50-pin male ribbon-cable rear connector  
68-pin male ribbon-cable rear connector  
Output  
Environment  
Operating temperature  
Storage temperature  
Relative humidity  
0° to 50° C  
-55° to 150° C  
5% to 90% noncondensing  
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Appendix B  
Customer Communication  
For your convenience, this appendix contains forms to help you gather the information necessary  
to help us solve technical problems you might have as well as a form you can use to comment on  
the product documentation. Filling out a copy of the Technical Support Form before contacting  
National Instruments helps us help you better and faster.  
National Instruments provides comprehensive technical assistance around the world. In the U.S.  
and Canada, applications engineers are available Monday through Friday from 8:00 a.m. to  
6:00 p.m. (central time). In other countries, contact the nearest branch office. You may fax  
questions to us at any time.  
Corporate Headquarters  
(512) 795-8248  
Technical support fax: (800) 328-2203  
(512) 794-5678  
Branch Offices  
Australia  
Austria  
Belgium  
Denmark  
Finland  
France  
Germany  
Italy  
Phone Number  
(03) 879 9422  
(0662) 435986  
02/757.00.20  
45 76 26 00  
(90) 527 2321  
(1) 48 14 24 00  
089/741 31 30  
02/48301892  
(03) 3788-1921  
03480-33466  
32-848400  
Fax Number  
(03) 879 9179  
(0662) 437010-19  
02/757.03.11  
45 76 71 11  
(90) 502 2930  
(1) 48 14 24 14  
089/714 60 35  
02/48301915  
(03) 3788-1923  
03480-30673  
32-848600  
Japan  
Netherlands  
Norway  
Spain  
Sweden  
Switzerland  
U.K.  
(91) 640 0085  
08-730 49 70  
056/20 51 51  
0635 523545  
(91) 640 0533  
08-730 43 70  
056/20 51 55  
0635 523154  
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Technical Support Form  
Photocopy this form and update it each time you make changes to your software or hardware, and use the completed  
copy of this form as a reference for your current configuration. Completing this form accurately before contacting  
National Instruments for technical support helps our applications engineers answer your questions more efficiently.  
If you are using any National Instruments hardware or software products related to this problem, include the  
configuration forms from their user manuals. Include additional pages if necessary.  
Name  
Company  
Address  
Fax (  
Computer brand  
Operating system  
)
Phone (  
Model  
)
Processor  
Speed  
MHz  
RAM  
no  
MB  
Display adapter  
Mouse  
yes  
Other adapters installed  
Brand  
Hard disk capacity  
Instruments used  
MB  
National Instruments hardware product model  
Configuration  
Revision  
National Instruments software product  
Configuration  
Version  
The problem is  
List any error messages  
The following steps will reproduce the problem  
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SC-2040 Hardware and Software  
Configuration Form  
Record the settings and revisions of your hardware and software on the line to the right of each item. Complete a  
new copy of this form each time you revise your software or hardware configuration, and use this form as a  
reference for your current configuration. Completing this form accurately before contacting National Instruments  
for technical support helps our applications engineers answer your questions more efficiently.  
National Instruments Products  
•
•
•
•
•
DAQ Hardware Revision  
Interrupt Level of Hardware  
DMA Channels of Hardware  
Base I/O Address of Hardware  
NI-DAQ Version  
__________________________________________________  
__________________________________________________  
__________________________________________________  
__________________________________________________  
Other Products  
•
•
•
•
•
•
•
•
•
•
•
•
•
Computer Make and Model  
Microprocessor  
__________________________________________________  
__________________________________________________  
__________________________________________________  
Clock Frequency  
Type of Video Board Installed  
Operating System  
__________________________________________________  
__________________________________________________  
__________________________________________________  
__________________________________________________  
__________________________________________________  
__________________________________________________  
__________________________________________________  
__________________________________________________  
__________________________________________________  
Operating System Version  
Operating System Mode  
Programming Language  
Programming Language Version  
Other Boards in System  
Base I/O Address of Other Boards  
DMA Channels of Other Boards  
Interrupt Level of Other Boards  
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Documentation Comment Form  
National Instruments encourages you to comment on the documentation supplied with our products. This  
information helps us provide quality products to meet your needs.  
Title: SC-2040 User Manual  
Edition Date:  
Part Number:  
September 1994  
371191A-01  
Please comment on the completeness, clarity, and organization of the manual.  
If you find errors in the manual, please record the page numbers and describe the errors.  
Thank you for your help.  
Name  
Title  
Company  
Address  
Phone  
(
)
Mail to:  
Technical Publications  
Fax to:  
Technical Publications  
National Instruments Corporation  
MS 53-02  
National Instruments Corporation  
6504 Bridge Point Parkway, MS 53-02  
Austin, TX 78730-5039  
(512) 794-5678  
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Glossary  
___________________________________________________  
Prefix  
Meaning  
Value  
p-  
n-  
µ-  
m-  
k-  
pico-  
nano-  
micro-  
milli-  
kilo-  
-12  
10  
10  
10  
10  
-9  
-6  
-3  
3
10  
10  
6
M-  
mega-  
˚
degrees  
ohms  
amperes  
Ω
A
ACH#  
A/D  
Arms  
AWG  
C
CH#+  
CH#-  
CMOS  
cps  
DAQ board analog input channel number  
analog-to-digital  
amperes, root mean square  
American Wire Gauge  
Celsius  
module positive input channel number  
module negative input channel number  
complementary metallic oxide semiconductor  
counts per second  
digital-to-analog  
data acquisition  
decibels  
D/A  
DAQ  
dB  
DC  
direct current  
DIN  
DIP  
FIFO  
hex  
Deutsche Industrie Norme  
dual inline package  
first-in-first-out  
hexadecimal  
Hz  
in.  
hertz  
inches  
II  
input current leakage  
I
input current  
in  
I/O  
input/output  
output current  
I
out  
LED  
LSB  
m
MB  
MSB  
ppm  
light-emitting diode  
least significant bit  
meters  
megabytes  
most significant bit  
parts per million  
© National Instruments Corporation  
Glossary-1  
SC-2040 User Manual  
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Glossary  
RAM  
rms  
s
SPI  
tempco  
T/H  
UL  
random-access memory  
root mean square  
seconds  
serial peripheral interface  
temperature coefficient  
track-and-hold  
Underwriters Laboratory  
volts  
V
VI  
V
IH  
VIL  
virtual instrument  
volts input high  
volts input low  
V
V
V
V
volts in  
in  
volts output high  
volts output low  
volts out  
OH  
OL  
out  
VAC  
VDC  
Vrms  
volts alternating current  
volts direct current  
volts, root mean square  
SC-2040 User Manual  
Glossary-2  
© National Instruments Corporation  
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Index  
common-mode input range, 3-10  
to 3-11  
Numbers/Symbols  
exceeding differential and  
common-mode ranges  
(warning), 3-10  
+5 V signal  
input connector summary (table), 3-4  
output connector summary (table), 3-4  
to 3-5  
floating AC-coupled signal  
connection (illustration), 3-10  
ground-offset AC-coupled signal  
connection (illustration), 3-9  
ground-referenced AC-coupled  
signal connection (illustration), 3-9  
referencing analog ground to DAQ  
board (note), 3-8  
A
AC-coupled inputs, 3-8 to 3-11  
common-mode input range, 3-10 to 3-11  
exceeding differential and  
common-mode ranges (warning), 3-10  
floating AC-coupled signal connection  
(illustration), 3-8  
analog input ranges, 3-10 to 3-11  
DC-coupled inputs, 3-7 to 3-8  
floating signal connection  
(illustration), 3-8  
ground-offset AC-coupled signal  
connection (illustration), 3-9  
ground-referenced AC-coupled signal  
connection (illustration), 3-9  
referencing analog ground to DAQ  
board (note), 3-8  
ground-referenced signal connection  
(illustration), 3-7  
leaving connector J5 disconnected  
(note), 3-7  
AIGND-AIGND position (table), 2-4  
AIGND-DGND position (table), 2-4  
AIGND signal  
B
block diagram of SC-2040, 4-2  
board configuration. See configuration.  
input connector summary (table), 3-4  
output connector summary (table), 3-4  
to 3-5  
analog circuitry, 4-2 to 4-6  
amplification, 4-3  
C
external triggering, 4-5 to 4-6  
input protection, 4-3  
calibration procedures  
hardware calibration, 5-2 to 5-4  
calibration component identification  
(table), 5-3  
output connection, 4-6  
power supply, 4-6  
track-and-hold (T/H) circuitry, 4-3 to 4-4  
triggering from DAQ board, 4-4 to 4-5  
analog input specifications  
amplifier characteristics, A-2  
dynamic characteristics, A-2  
input characteristics, A-1  
S/H characteristics, A-3  
stability, A-3  
transfer characteristics, A-1  
analog signal inputs, 3-7 to 3-11  
AC-coupled inputs, 3-8 to 3-11  
steps for, 5-3 to 5-4  
overview, 5-1  
software calibration  
gain adjustment, 5-2  
linearity adjustment, 5-2  
offset adjustment, 5-1  
CH-(0..7) signal (table), 3-3  
channel gain selection  
gain switches for each channel  
(table), 2-6  
© National Instruments Corporation  
Index-1  
SC-2040 User Manual  
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Index  
procedure for, 2-6 to 2-7  
switch settings (table), 2-7  
table, 2-5  
output connector summary (table), 3-4  
to 3-5  
digital signal inputs, 3-9  
documentation  
channel input mode (table), 2-5  
CH+(0..7) signal (table), 3-4  
common-mode input range, 3-10 to 3-11  
configuration  
conventions used in manual, x  
National Instruments documentation  
set, x  
channel gain selection  
gain switches for each channel  
(table), 2-6  
organization of manual, ix  
related documentation, xi  
procedure for, 2-6 to 2-7  
switch settings (table), 2-7  
table, 2-5  
E
channel input mode (table), 2-5  
DAQ board ground isolation selection  
procedure for, 2-6  
environment specifications, A-3  
equipment, optional, 1-4  
EXT switch position (table), 2-3  
table, 2-4  
input mode selection, 2-7  
parts locator diagram, 2-2  
power supply selection  
procedure for, 2-6  
table, 2-3  
shield selection  
F
floating AC-coupled signal connection  
(illustration), 3-10  
floating signal connection (illustration), 3-8  
procedure for, 2-4  
table, 2-4  
connectors J11 and J12  
overview, 3-1  
G
pin assignments (illustration), 3-2  
(table), 3-3  
signal routing (illustration), 3-6  
signal summary (table), 3-4  
customer communication, xi, B-1  
gain selection. See channel gain selection.  
ground-offset AC-coupled signal connection  
(illustration), 3-9  
ground-referenced AC-coupled signal  
connection (illustration), 3-9  
ground-referenced signal connection  
(illustration), 3-7  
D
H
DAQ board ground isolation selection  
procedure for, 2-6  
hardware calibration.  
See calibration procedures.  
hold-mode settling time, 4-3  
table, 2-4  
DC-coupled inputs, 3-7 to 3-8  
floating signal connection  
(illustration), 3-8  
I
ground-referenced signal connection  
(illustration), 3-7  
leaving connector J5 disconnected  
(note), 3-7  
input connectors signal summary (table), 3-4  
input mode selection, 2-7  
installation  
DGND signal  
power-on sequence, 2-8  
steps for, 2-8  
input connector summary (table), 3-4  
SC-2040 User Manual  
Index-2  
© National Instruments Corporation  
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Index  
unpacking the SC-2040, 1-4  
instrumentation amplifiers, 4-3  
INT switch position (table), 2-3  
R
register-level programming, 1-4  
J
S
J11 and J12 connectors. See connectors J11  
and J12.  
jumpers and switches. See configuration.  
SC-2040  
block diagram, 4-2  
features, 1-1  
I/O connectors (J11 and J12),  
(illustration), 3-2  
L
LabVIEW and LabWindows application  
software, 1-2  
optional equipment, 1-4  
required components, 1-1  
software programming choices  
LabVIEW and LabWindows  
application software, 1-2  
NI-DAQ driver software, 1-2 to 1-3  
register-level programming, 1-4  
unpacking, 1-4  
M
manual. See documentation.  
MIO-16E DAQ board, triggering, 4-4 to 4-5  
monitoring signal inputs, 3-11  
shield selection  
procedure for, 2-4  
table, 2-4  
SHLD OFF jumper position (table), 2-4  
SHLD ON jumper position (table), 2-4  
signal connections  
O
operation of SC-2040. See theory  
of operation.  
output connection, 4-6  
output connectors (J11 and J12) signal  
summary (table), 3-4 to 3-5  
analog signal inputs, 3-7 to 3-1  
AC-coupled inputs, 3-10 to 3-11  
analog input ranges, 3-10 to 3-11  
DC-coupled inputs, 3-7 to 3-8  
connections exceeding maximum ratings  
(warning), 3-1  
digital signal inputs, 3-11  
input connectors signal summary  
(table), 3-4  
monitoring signal inputs, 3-11  
other connection considerations, 3-11  
output connectors (J11 and J12) signal  
summary (table), 3-4 to 3-5  
SC-2040 I/O connectors J11 and J12  
(illustration), 3-2  
P
parts locator diagram, 2-2  
physical specifications, A-3  
pin assignments for SC-2040 I/O connectors  
J11 and J12 (table), 3-3  
power-on sequence, 2-8  
power supply  
description, 4-6  
selecting  
procedure for, 2-6  
table, 2-3  
specifications, A-3  
signal routing (illustration), 3-6  
signal outputs, monitoring, 3-11  
software calibration.  
See calibration procedures.  
software programming choices  
LabVIEW and LabWindows application  
software, 1-2  
NI-DAQ driver software, 1-2 to 1-3  
© National Instruments Corporation  
Index-3  
SC-2040 User Manual  
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Index  
register-level programming, 1-4  
specifications  
analog input  
amplifier characteristics, A-2  
dynamic characteristics, A-2  
input characteristics, A-1  
S/H characteristics, A-3  
stability, A-3  
transfer characteristics, A-1  
environment, A-3  
physical, A-3  
power requirements, A-3  
T
technical support, B-1  
theory of operation  
analog circuitry, 4-2 to 4-6  
amplification, 4-3  
external triggering, 4-5 to 4-6  
input protection, 4-3  
output connection, 4-6  
power supply, 4-6  
track-and-hold (T/H) circuitry, 4-3  
to 4-4  
triggering from DAQ board, 4-4  
to 4-5  
block diagram, 4-2  
functional overview, 4-1  
track-and-hold (T/H) circuitry, 4-3 to 4-4  
TRIG signal  
description (table), 3-4  
susceptibility to noise, 3-11  
TRIG (PF12) signal (table), 3-4  
triggering  
from DAQ board, 4-4 to 4-5  
external  
digital signal inputs, 3-11  
illustration, 4-6  
theory of operation, 4-5 to 4-6  
U
unity gain position (table), 2-5  
unpacking the SC-2040, 1-4  
SC-2040 User Manual  
Index-4  
© National Instruments Corporation  
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