Sierra Flat Traktm 780s User Manual

Sierra 780S Series Flat-Trak™  
Mass Flow Meter  
Instruction Manual  
Part Number IM-78S  
07/99 Revision B  
5 Harris Court, Building L Monterey, CA 93940  
(831) 373-0200 (800) 866-0200 Fax (831) 373-4402  
Sierra Instruments b.v. Bolstoen 30A 1046 AV Amsterdam The Netherlands  
+31(0)20-6145810 Fax +31(0)20-6145815  
Series 780S Instruction Manual  
Table of Contents  
Table of Contents  
Chapter 1 Introduction  
Series 780S Flat-Trak Mass Flow Meters ..........................1-1  
Using this Manual.................................................1-1  
Note and Safety Information.....................................1-2  
Receipt of System Components .................................1-2  
Technical Assistance..............................................1-2  
The Series 780S Flow Sensing Principle...........................1-3  
Smart Electronics Features............................................1-4  
Enclosure Options .....................................................1-5  
Smart InterfaceSoftware............................................1-5  
Chapter 2 Installation and Wiring  
Installation Overview..................................................2-1  
Unobstructed Flow Requirements...............................2-2  
Installing the Flow Meter .............................................2-2  
Changing Display Orientation....................................2-3  
Wiring Connections ...................................................2-4  
Input Power Wiring...............................................2-5  
Output Signal Wiring .............................................2-7  
Alarm Output Wiring.............................................2-10  
Remote Sensor Probe Wiring...................................2-11  
Range Selection Wiring..........................................2-13  
Chapter 3 Operating Instructions  
Flow Meter Start Up...................................................3-1  
Using the Smart Electronics Basic Features........................3-2  
Hazardous-Area Enclosure Optional LCD Display............3-2  
LCD Display Programming Menu...............................3-3  
Single-Digit LED Programming Menu..........................3-4  
Entering Alarm Parameters.......................................3-5  
K-Factor Adjustment..............................................3-6  
User Full Scale Adjustment......................................3-7  
Time Response Delay Adjustment...............................3-8  
Totalizer Reset.....................................................3-9  
Using the Smart Electronics Advanced Features..................3-11  
Voltage Zero Adjustment........................................3-11  
Voltage Span Adjustment........................................3-11  
Current Zero Adjustment........................................3-12  
Current Span Adjustment........................................3-12  
Instrument Validation.................................................3-13  
Electronics Validation Procedure...............................3-14  
Sensor Validation Procedure....................................3-15  
IM-78S-B  
0-3  
Table of Contents  
Series 780S Instruction Manual  
Chapter 4 Troubleshooting and Repair  
Troubleshooting the Flow Meter.....................................4-1  
Returning Equipment to the Factory.................................4-3  
Appendix A Product Specifications  
List of Figures  
1-1. Series 780S Flow Sensing Principle .......................1-3  
2-1. Flow Meter Orientation.......................................2-2  
2-2. Wiring Access NEMA 4X Enclosures .....................2-4  
2-3. Wiring Access Hazardous-Area Enclosures...............2-4  
2-4. AC Input Power Connections...............................2-5  
2-5. Ferrite Clamp Installation....................................2-5  
2-6. DC Input Power Connections (NEMA 4X) ...............2-6  
2-7. DC Input Power Connections (Hazardous-Area).........2-6  
2-8. DC Output Signal Connections (NEMA 4X)..............2-7  
2-9. DC Output Signal Connections (Hazardous-Area)........2-7  
2-10. Load Resistance Versus Input Voltage.....................2-8  
2-11. Isolated 4-20 mA Loop (NEMA 4X).......................2-9  
2-12. Non-isolated 4-20 mA Loop (NEMA 4X).................2-9  
2-13. Isolated 4-20 mA Loop (Hazardous-Area).................2-9  
2-14. Non-isolated 4-20 mA Loop (Hazardous-Area)...........2-9  
2-15. Isolated Alarm Connections (NEMA 4X).................2-10  
2-16. Non-Isolated Alarm Connections (NEMA 4X) ..........2-10  
2-17. Isolated Alarm Connections (Hazardous-Area) ..........2-11  
2-18. Non-isolated Alarm Connections (Hazardous-Area) ....2-11  
2-19. Remote Electronics to Sensor (NEMA 4X)...............2-12  
2-20. J Box to Remote Enclosure (NEMA 4X).................2-12  
2-21. Remote Electronics to Sensor (Hazardous-Area) ........2-12  
2-22. J Box to Remote Enclosure (Hazardous-Area)...........2-13  
2-23. Range Selection Wiring (NEMA 4X) .....................2-13  
2-24. Range Selection Wiring (Hazardous-Area)...............2-13  
3-1. Smart Electronics Device Locations ........................3-1  
3-2. Magnetic Switch Operation..................................3-2  
3-3. Electronics Validation Component Locations.............3-13  
3-4. Sensor Validation Component Locations .................3-15  
List of Tables  
2-1. Pipe Length Requirements for Installation.................2-2  
3-1. Electronics Validation Results..............................3-15  
3-2. Sensor Validation Results...................................3-16  
0-4  
IM-78S-B  
Series 780S Instruction Manual  
Table of Contents  
Warnings and Cautions  
Warning! Agency approval for hazardous location installations varies between flow  
meter models. Consult the flow meter nameplate for specific flow meter approvals be-  
fore any hazardous location installation.  
Warning! All wiring procedures must be performed with the power off.  
Warning! To avoid potential electric shock, follow National Electric Code safety practices  
or your local code when wiring this unit to a power source and to peripheral devices. Fail-  
ure to do so could result in injury or death. All AC power connections must be in accor-  
dance with published CE directives.  
Warning! Do not power the flow meter with the sensor jumper wires disconnected. This  
could cause over-heating of the sensors and/or damage to the electronics.  
Warning! Before attempting any flow meter repair, verify that the line is de-pressurized.  
Warning! Always remove main power before disassembling any part of the mass flow meter.  
Caution! Changing the length of cables or interchanging sensors or sensor wiring  
will affect the accuracy of the flow meter. You cannot add or subtract wire length with-  
out returning the meter to the factory for re-calibration.  
Caution! When using toxic or corrosive gases, purge the line with inert gas for a  
minimum of four hours at full gas flow before installing the meter.  
Caution! The AC wire insulation temperature rating must meet or exceed 71°C (158°F).  
Caution! Before making adjustments to the Smart Electronics device, verify the flow meter  
is not actively monitoring or reporting to any master control system. Adjustments to the  
electronics will cause direct changes to flow control settings.  
Caution! Printed circuit boards are sensitive to electrostatic discharge. To avoid  
damaging the board, follow these precautions to minimize the risk of damage:  
·
before handling the assembly, discharge your body by touching a grounded,  
metal object  
·
·
handle all cards by their edges unless otherwise required  
when possible, use grounded electrostatic discharge wrist straps when handling  
sensitive components  
IM-78S-B  
0-5  
Table of Contents  
Series 780S Instruction Manual  
0-6  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 1 Introduction  
Chapter 1 Introduction  
Series 780S Flat-TrakMass Flow Meters  
Sierra’s Series 780S Flat-Trak Mass Flow Meter provides a reliable  
solution for monitoring gas mass flow rate. Low-flow sensitivity,  
fast response and outstanding rangeability have made this model the  
instrument of choice for many critical gas flow applications. The  
Series 780S meter solves the problems associated with monitoring  
flow in installations where long runs of straight pipe are not avail-  
able. The instrument’s built-in flow conditioner creates a uniform  
velocity profile by means of two stainless-steel perforated plates  
welded into the body between the sensor and the inlet connection.  
With flow conditioning, upstream piping requirements are reduced  
to less than three diameters after most common flow disturbances.  
The flow meter’s versatile microprocessor-based transmitter integrates  
the functions of flow-range adjustment, meter validation and diagnos-  
tics in a probe-mounted or remotely mounted housing. Mass flow rate  
and totalized flow, as well as other configuration variables are dis-  
played on the meter’s optional LCD display. The meter provides an  
optical/galvanic isolated flow output, two alarm outputs and one con-  
tact input for range or gas selection. The programmable transmitter is  
easily configured via RS-232 and Sierra’s Smart Interfacesoftware  
or through three push buttons built into the device.  
The Series 780S Mass Flow Meter’s simple installation combines  
with an easy-to-use interface that provides quick set up, long term  
reliability and accurate mass flow measurement over a wide range of  
flows and conditions.  
Using This Manual  
This manual provides the information you need to install and operate  
the Series 780S Mass Flow Meter. The four chapters of this manual  
cover the following areas:  
·
·
·
·
Chapter 1 includes the introduction and product description  
Chapter 2 provides installation and wiring instructions  
Chapter 3 describes system operation and programming  
Chapter 4 covers troubleshooting and repair  
The product specifications are found in Appendix A.  
IM-78S-B  
1-1  
Chapter 1 Introduction  
Series 780S Instruction Manual  
Note and Safety Information  
We use note, caution and warning statements throughout this book  
to draw your attention to important information.  
Warning!  
Caution!  
Note  
This statement appears with  
information that is important to  
protect people and equipment  
from damage. Pay very close  
attention to all warnings that  
apply to your application.  
This statement appears with  
information that is important  
for protecting your equipment  
and performance. Read and  
follow all cautions that apply  
to your application.  
This statement appears with  
a short message to alert you  
to an important detail.  
Receipt of System Components  
When receiving a Sierra mass flow meter, carefully check the outside  
packing carton for damage incurred in shipment. If the carton is dam-  
aged, notify the local carrier and submit a report to the factory. Re-  
move the packing slip and check that all ordered components are pre-  
sent. Make sure any spare parts or accessories are not discarded with  
the packing material. Do not return any equipment to the factory  
without first contacting Sierra Customer Service.  
Technical Assistance  
If you encounter a problem with your flow meter, review the con-  
figuration information for each step of the installation, operation and  
setup procedures. Verify that your settings and adjustments are con-  
sistent with factory recommendations. Refer to Chapter 4, Trouble-  
shooting, for specific information and recommendations.  
If the problem persists after following the troubleshooting procedures  
outlined in Chapter 4, contact Sierra Instruments by fax or by E-mail  
(see inside front cover). For urgent phone support you may call (800)  
866-0200 or (831) 373-0200 between 8:00 a.m. and 5:00 p.m. PST.  
In Europe contact Sierra Instruments bv at +31 20 6145810. When  
contacting Technical Support, make sure to include this information:  
·
the flow range, serial number and Sierra order  
number (all marked on the meter nameplate)  
·
·
the software version (visible at start up)  
the problem you are encountering and any corrective  
action taken  
·
application information (gas, pressure, temperature  
and piping configuration)  
1-2  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 1 Introduction  
The Series 780S Flow Sensing Principle  
Sierra’s unique Steel-Traksensor probe is responsible for the un-  
surpassed accuracy, ruggedness and reliability of Sierra industrial  
flow meters. The immersible Steel-Trak sensor consists of two  
sensing elements–a velocity sensor and a temperature sensor that  
automatically corrects for changes in gas temperature.  
When power is applied to the flow meter, the transducer electronics  
heats the velocity sensor to a constant temperature differential above  
the gas temperature and measures the cooling effect of the gas flow.  
The electrical power required to maintain a constant temperature dif-  
ferential is directly proportional to the gas mass flow rate.  
Both sensors are reference-grade platinum resistance temperature  
detectors (RTDs). The platinum RTD wire is wound on a rugged ce-  
ramic mandrel for strength and stability. Steel-Trak sensors are clad  
in a rugged, sealed 316 stainless steel encasement.  
Figure 1-1. Series 780S Flow Sensing Principle  
IM-78S-B  
1-3  
Chapter 1 Introduction  
Series 780S Instruction Manual  
Smart Electronics Features  
Instrument Validation  
Two simple tests offer full “field-validation” of your Smart mass  
flow meter. The first test checks the system electronics, linearization  
and microprocessor functionality and is performed by injecting a  
known input value and confirming that the flow meter outputs the  
expected value. The second test verifies that the instrument’s pri-  
mary sensing elements have not drifted or shifted from their original  
calibration and is accomplished by measuring the resistance of the  
velocity and temperature sensors and comparing the results to the  
NIST-traceable calibration data provided with the flow meter. To-  
gether, these tests confirm that your meter is working correctly and  
the calibration variables did not drift, shift or change values.  
Dual Range or Dual Gas Calibration (Optional)  
Select one of two factory calibrated flow ranges using a simple ex-  
ternal customer-supplied single contact closure.  
User Full Scale Flow Rate  
Field-configure from 50% to 100% of the factory full scale setting  
(factory full scale is normally set to 125% of the user-specified maxi-  
mum flow rate). This adjustment can be made for each flow range.  
Alarms  
Program high and low or window alarm limits independently for  
each flow range. The solid state contacts are optically isolated.  
K-Factor Correction  
Change the calibration correction factor to compensate for flow pro-  
file disturbances or specific application conditions. The K-factor is a  
multiplication factor applied to the linearized flow signal. You may  
set the K-factor individually for each flow range.  
Dual Output Signals  
The flow meter offers two separate linear output signals propor-  
tional to flow, 0-5 VDC (0-10 VDC optional) and 4-20 mA. The  
4-20 mA output can be field-configured as an active loop powered  
by the flow meter or an optically isolated passive loop requiring an  
external power supply.  
1-4  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 1 Introduction  
Totalizer  
With the optional LCD display, actual mass flow appears on line 1  
and the totalized flow on line 2 both in the user-specified engineer-  
ing units. The totalizer counts only the selected range and when  
ranges are switched, the value of the non-selected range is stored in  
memory. You may reset the totalizer using the membrane buttons or  
by using a hand-held magnet.  
Zero and Span Outputs  
Validate and adjust the settings to ensure output circuits are correct.  
Time Response Delay  
Select from a low response for faster tracking to a high response  
for a smoother output.  
Enclosure Options  
Flow meter electronics are available mounted directly to the flow  
body, or remotely mounted up to 200 feet away. The electronics  
housing may be used indoors or out, including wet environments.  
Display options include a 2 x 12 character LCD display of mass flow  
rate including totalized mass, or a single-digit LED located on the de-  
vice printed circuit board. Local operation and reconfiguration is ac-  
complished using the three push buttons operated via finger touch.  
Smart electronics include nonvolatile memory that stores all configu-  
ration information. The memory allows the flow meter to function  
immediately upon power up, or after an interruption in power.  
Smart InterfaceSoftware  
Sierra’s Smart Interface Windows-based software is available for  
connecting your PC directly to the mass flow meter. An RS-232 se-  
rial cable along with floppy disks containing the program and sys-  
tem files are available from the factory. See the Smart Interface User  
Guide included with the software package for operating instructions.  
(Order code for this package is 780-SIP.)  
IM-78S-B  
1-5  
Chapter 1 Introduction  
Series 780S Instruction Manual  
1-6  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 2 Installation  
Chapter 2 Installation  
Installation Overview  
The Series 780S Flat-Trakis available with ANSI or DIN flanges,  
NPT or butt-weld connections. For ease of installation, the meter is  
pre-assembled with the sensor probe installed in the flow body.  
Warning!  
Agency approval for hazardous  
location installations varies  
between flow meter models.  
Consult the flow meter name-  
plate for specific flow meter  
approvals before any hazard-  
ous location installation.  
When selecting an installation site, make sure that:  
1. Line pressure and temperature will not exceed the flow meter  
rating. Temperature should not vary more than 200°F (100°C)  
around the calibration temperature. Line pressure should not  
vary more than 50 psi (3.4 bar) around the calibrated pressure.  
2. The location meets the required minimum number of pipe  
diameters upstream and downstream of the sensor head (see  
Table 2-1).  
3. Safe and convenient access with adequate clearance. Also, verify  
the meter is located where the gas is clean and dry and the meter  
is calibrated for the gas to be measured.  
4. When using a CSA, FM or EEx approved flow meter, verify that  
the cable entry into the instrument meets the specific standard re-  
quired for that approval.  
5. For remote installations, verify the supplied cable length is suffi-  
cient to connect the flow meter sensor to the remote electronics.  
(Do not extend or shorten the supplied cable between the probe  
and the electronics.)  
Also, before installation check your flow system for anomalies  
such as:  
·
·
leaks  
valves or restrictions in the flow path that could create dis-  
turbances in the flow profile that might cause unexpected  
flow rate indications  
·
heaters that might cause rapid excursions in the measured  
temperature  
IM-78S-B  
2-1  
Chapter 2 Installation  
Series 780S Instruction Manual  
Unobstructed Flow Requirements  
Select an installation site that will minimize possible distortion in the  
flow profile. Valves, elbows, control valves and other piping compo-  
nents may cause flow disturbances. Check your specific piping condi-  
tion against the examples shown below. To achieve accurate and re-  
peatable performance, install the flow meter using the recommended  
number of straight run pipe diameters upstream of the sensor.  
Piping Condition  
Single 90° elbow or T-piece  
Reduction (4:1)  
Upstream(1) Requirements  
1 D  
3 D  
3 D  
3 D  
3 D  
5 D  
Expansion  
After a control valve  
Two 90° elbows (in same plane)  
Two 90° elbows (different planes)  
(1) Number of diameters (D) of straight pipe required between upstream disturbance and the flow meter sensor.  
Table 2-1. Pipe Length Requirements for Installation  
Installing the Flow Meter  
Enclosure  
adjustable to any  
viewing position  
SIERRA  
Flow direction indicator  
should point downstream  
in the direction of flow  
FLOW  
Figure 2-1. Flow Meter Orientation (Flange Connection Shown)  
When positioning the flow meter, refer to the flow direction indicator  
attached to the probe. For proper operation, install the meter with the  
flow direction indicator pointing downstream in the direction of flow.  
Installing the meter opposite this direction may result in inaccurate  
flow measurement.  
2-2  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 2 Installation  
To install the flow meter:  
1. Turn off the flow of process gas. Verify that the line is not pres-  
surized. Confirm that the installation site meets the minimum up-  
stream pipe diameter requirements shown in Table 2-1.  
Caution!  
When using toxic or cor-  
rosive gases, purge the  
line with inert gas for a  
minimum of four hours at  
full gas flow before in-  
stalling the flow meter.  
2. Prepare the fluid connection fittings or flanges in the pipeline.  
(Fitting components should be blown clean with filtered gas be-  
fore use.) Mount in a vertical position. For horizontal pipelines  
having a process gas temperature above 300° F (130°C), mount the  
flow meter at a 90-degree angle to avoid overheating the electron-  
ics enclosure.  
3. Seat the flow meter level and square on the mating fluid connec-  
tions with a gasket in place for each side for flange types. (Make  
sure both gaskets are smooth and even with no gasket material  
protruding into the flow profile; obstructions in the pipeline could  
cause inaccurate flow measurement.) Make sure that the flow di-  
rection indicator is pointing downstream in the direction of flow.  
4. Secure the fluid connections as specified in the technical guidelines  
furnished by the fitting or flange manufacturer.  
5. If needed, adjust the optional display to the desired orientation,  
as follows.  
Changing Display Orientation (Hazardous-Area Enclosures Only)  
Depending on installation requirements, you may need to change the  
position of the optional display. To rotate the display board:  
1. Use a 1/16-inch hex key to loosen the set screw securing the  
larger end of the enclosure. Turn cover counterclockwise and  
remove.  
2. Remove 4 screws and standoffs from the display. Release the  
latch securing the display ribbon cable connector from the dis-  
play board.  
3. Rotate the display board to the desired position. Re-connect the  
ribbon cable to the display board.  
4. Replace the 4 screws and standoffs. Replace the enclosure  
cover. Tighten set screw.  
IM-78S-B  
2-3  
Chapter 2 Installation  
Series 780S Instruction Manual  
Wiring Connections  
For NEMA 4X enclosures, use TB2 for power and signal connec-  
tions, TB1 is for sensor connections. (The terminal designations are  
labeled inside the enclosure cover.)  
Warning!  
To avoid potential electric  
shock, follow National Elec-  
tric Code safety practices or  
your local code when wiring  
this unit to a power source  
and to peripheral devices.  
Failure to do so could result  
in injury or death. All AC  
power connections must be  
in accordance with pub-  
lished CE directives.  
Wiring connections  
inside cover  
NEMA 4X enclosure  
terminal blocks  
TB2  
1
2
4
6
8
3
5
7
9
11  
13  
15  
10  
TB1  
12  
14  
16  
6
4
2
5
3
1
To access components:  
1. Loosen 4 screws.  
2. Remove cover.  
Figure 2-2. Wiring Access NEMA 4X Enclosures  
For Hazardous-Area enclosures, use the terminal blocks located in-  
side the smaller end of the flow meter enclosure for all wiring con-  
nections. (The terminal designations are labeled inside the enclosure  
cover.) Make sure to observe all CE compliance requirements for  
AC wiring connections given on the next page.  
Hazardous-Area enclosure  
Set screw  
Wiring  
terminal blocks  
1
2
3
4
5
6
7
8
9
20  
19  
18  
17  
16  
15  
14  
13  
12  
connections  
10 11  
To access components:  
1. Use 1/16 inch hex key to loosen set screw.  
2. Turn cover counterclockwise to remove.  
Figure 2-3. Wiring Access Hazardous-Area Enclosures  
2-4  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 2 Installation  
Input Power Wiring  
AC Power Wiring  
The AC power wire size must be 26 to 16 AWG with the wire  
stripped 1/4 inch (6 mm). Connect 100 to 240 VAC (300 mA load,  
maximum) to the Neutral and Line terminals on the small, two-  
position terminal block. Connect the ground wire to the safety ground  
lug. Torque all connections to 4.43 to 5.31 in-lbs (0.5 to 0.6 Nm).  
Warning!  
All wiring procedures must  
be performed with the power  
Off.  
For all installations not using solid metal conduit, the ferrite clamp  
must be installed just above the input power wire entry into the en-  
closure (Figure 2-5). All EEx installations must use an approved  
EEx fitting at both cable entries into the enclosure. If conduit seals  
are used, they must be installed with 18 inches of the enclosure.  
Caution!  
The AC wire insulation tem-  
perature rating must meet or  
exceed 71°C (158°F).  
The Hazardous-Area enclosure has two separate conduit entries to  
maintain separation between AC input power and output signal wir-  
ing. To eliminate the possibility of noise interference use a separate  
cable entry for the AC power and signal lines.  
Hazardous-Area Enclosures  
AC Power (Neutral)  
AC Power (Line)  
1
2
3
4
5
6
7
8
9
20  
19  
18  
17  
16  
15  
14  
13  
12  
10 11  
Enclosure  
safety  
ground lug  
Figure 2-4. AC Input Power Connections  
Figure 2-5. Ferrite Clamp Installation  
IM-78S-B  
2-5  
Chapter 2 Installation  
Series 780S Instruction Manual  
DC Power Wiring  
The DC power wire size must be 26 to 16 AWG with the wire  
stripped 1/4 inch (6 mm). Connect 18 to 30 VDC (625 mA load,  
maximum) to the terminals marked PWR+ and PWR– on the terminal  
block. Torque all connections to 4.43 to 5.31 in-lbs (0.5 to 0.6 Nm).  
Warning!  
All wiring procedures  
must be performed with  
the power Off.  
All EEx installations must use an approved EEx fitting at both cable  
entries into the enclosure. If conduit seals are used, they must be in-  
stalled within 18 inches of the enclosure.  
NEMA 4X Enclosures  
1
DC Power (+)  
2
DC Power (–)  
15  
16  
Figure 2-6. DC Input Power Connections  
Hazardous-Area Enclosures  
DC Power (+)  
1
2
3
4
5
6
7
8
9
20  
19  
18  
17  
16  
15  
14  
13  
12  
DC Power (–)  
10 11  
Figure 2-7. DC Input Power Connections  
2-6  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 2 Installation  
Output Signal Wiring  
Output signal cable should be completely screened with a 100%  
shield. You must use metal cable glands that provide cable screen  
clamping. The cable screen should be connected to the gland and  
shielded at both ends over 360 degrees. The shield should be ter-  
minated to an earth ground.  
Flow meters are equipped with either a calibrated 0-5 VDC (0-10  
VDC optional) or a calibrated 4-20 mA output signal. This linear  
output signal represents 0-100% of the flow meter’s user full  
scale.  
DC Output Wiring  
The 0-5 VDC (0-10 VDC optional) signal can drive a minimum load  
of 1000 Ohms. Note: the optional 0-10 VDC output signal is not  
available for power sources below 15 VDC.  
For 0-5 VDC or 0-10 VDC connections, connect to the terminals  
marked Vout (+) and Vout (–) as shown below.  
NEMA 4X Enclosures  
1
2
0-5 V out (+)  
0-5 V out (–)  
15  
16  
Figure 2-8. DC Output Signal Connections  
Hazardous-Area Enclosures  
1
2
3
4
5
6
7
8
9
20  
19  
18  
17  
16  
15  
14  
13  
12  
0-5 V out (+)  
0-5 V out (–)  
10 11  
Figure 2-9. DC Output Signal Connections  
IM-78S-B  
2-7  
Chapter 2 Installation  
Series 780S Instruction Manual  
4-20 mA Output Wiring  
The 4-20 mA current loop output can be self-powered (non-isolated)  
or externally powered (isolated). To use the 4-20 mA isolated output,  
an external 12 to 36 VDC power supply is required. The maximum  
loop resistance (load) for both types of current loop outputs are de-  
pendent upon the supply voltage and are given in Figure 2-10.  
Rload is the total resistance in the loop, including the wiring resis-  
tance. To calculate Rmax, the maximum Rload for the loop, use the  
maximum loop current, 20 mA. The voltage drop in the loop due to  
resistance is 20 mA times Rload and this drop is subtracted from the  
input voltage. Thus:  
Rmax the maximum load resistance = 50 (Vsupply – 7.5V)  
*
To use an external power supply for an isolated 4-20 mA output, con-  
nect as shown in Figure 2-11 or Figure 2-13. For an internally pow-  
ered, non-isolated 4-20 mA output, connect as shown in Figure 2-12  
or Figure 2-14.  
Vsupply  
(Volts)  
11 (min)  
12  
Rmax  
(Ohms)  
175  
225  
15  
375  
18  
525  
24  
825  
30  
36 (max)  
1,125  
1,425  
Figure 2-10. Load Resistance Versus Input Voltage  
2-8  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 2 Installation  
NEMA 4X Enclosures  
1
2
Current  
R load  
+
4-20 out (+)  
4-20 out (–)  
15  
16  
12 VDC  
to  
36 VDC  
Figure 2-11. Isolated 4-20 mA Current Loop Connections  
NEMA 4X Enclosures  
1
2
Jumper  
AUX PWR OUT  
Current  
R load  
4-20 out (+)  
V out (–)  
(Common)  
15  
16  
Figure 2-12. Non-Isolated 4-20 mA Current Loop Connections  
Hazardous-Area Enclosures  
1
2
3
4
5
6
7
8
9
20  
19  
18  
17  
16  
15  
14  
13  
12  
4-20 out (+)  
+
12 VDC  
to  
36 VDC  
10 11  
4-20 out (–) R load  
Current  
Figure 2-13. Isolated 4-20 mA Current Loop Connections  
Hazardous-Area Enclosures  
1
2
3
4
5
6
7
8
9
20  
19  
18  
17  
16  
15  
14  
13  
12  
Jumper  
Com  
Use either  
Pin 4 or 14,  
NOT BOTH  
4-20 out (–)  
10 11  
Current  
R load  
Figure 2-14. Non-Isolated 4-20 mA Current Loop Connections  
IM-78S-B  
2-9  
Chapter 2 Installation  
Series 780S Instruction Manual  
Alarm Output Wiring  
Two alarm outputs (Low Alarm and High Alarm) are included on the  
flow meter terminal block. The alarm outputs use optical relays that are  
normally-open single-pole relays with one common connection.  
There are two connection options for alarm outputs–the first with a sepa-  
rate power supply (isolated) and the second using the flow meter power  
supply (non-isolated). Use the first option with a separate power supply  
if a specific voltage is needed for the alarm output. Use the second (non-  
isolated) configuration if the voltage at the flow meter’s power supply is  
an acceptable driver voltage for the load connected. (Take into account  
that the current used by your alarm loads have to come from the flow  
meter’s power supply.) In either case, the voltage of the alarm output is  
the same as the voltage supplied to the circuit.  
To use an external power supply for an isolated alarm output, con-  
nect as shown in Figure 2-15 or Figure 2-17. To use the internally  
powered, non-isolated alarm output connect as shown in Figure 2-16  
or Figure 2-18. For a window alarm connect both outputs together.  
NEMA 4X Enclosures  
AC or DC  
power supply  
1
ALRM COM  
2
HI ALARM (–)  
LO ALARM (–)  
Load  
Load  
15  
16  
Figure 2-15. Isolated Alarm Output Connections  
NEMA 4X Enclosures  
1
2
Load  
Load  
ALRM COM  
COMMON  
AUX DC PWR OUT  
HI ALARM (–)  
LO ALARM (–)  
15  
16  
Figure 2-16. Non-Isolated Alarm Connections  
2-10  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 2 Installation  
Hazardous-Area Enclosures  
1
2
3
4
5
6
7
8
9
20  
19  
18  
17  
16  
15  
14  
13  
12  
ALRM COM  
AC or DC  
power supply  
Load  
Load  
HI ALARM (–)  
LO ALARM (–)  
10 11  
Figure 2-17. Isolated Alarm Output Connections  
Hazardous-Area Enclosures  
1
2
3
4
5
6
7
8
9
20  
19  
18  
17  
16  
15  
14  
13  
12  
DC POWER OUT  
Load  
Load  
HI ALARM (–)  
LO ALARM (–)  
10 11  
ALRM COM  
Figure 2-18. Non-Isolated Alarm Connections  
Remote Sensor Probe Wiring  
When connecting the sensor probe to a remotely mounted flow  
meter enclosure, use only factory supplied cables. The electronics,  
sensors and interconnecting cables supplied by Sierra Instruments  
are calibrated as a complete precision mass flow circuit.  
Caution!  
Changing the length of ca-  
bles or interchanging sen-  
sors or sensor wiring will af-  
fect the accuracy of the flow  
meter. You cannot add or  
subtract wire length without  
returning the meter to the fac-  
tory for recalibration.  
To connect the sensor probe to a remotely mounted electronics  
enclosure, see Figure 2-19 or Figure 2-21. To make wiring  
connections from a sensor probe junction box to a remotely  
mounted enclosure, see Figure 2-20 or Figure 2-22.  
IM-78S-B  
2-11  
Chapter 2 Installation  
Series 780S Instruction Manual  
NEMA 4X Enclosures  
Remote  
enclosure  
Sensor  
probe  
RED  
GREEN  
Temperature  
sensor  
Velocity  
sensor  
ORANGE  
WHITE  
BLACK  
Note: Sensor wire color may vary - see label in cover  
Figure 2-19. Remote Electronics Enclosure to Sensor Connections  
Figure 2-20. Sensor Junction Box to Remote Enclosure Connections  
Hazardous-Area Enclosures  
Sensor  
probe  
GREEN  
ORANGE  
1
2
3
4
5
6
7
8
9
20  
19  
18  
17  
16  
15  
14  
13  
12  
Remote  
enclosure  
RED  
WHITE  
BLACK  
10 11  
Note: Sensor wire color may vary - see label in cover  
Figure 2-21. Remote Electronics to Sensor Connections  
2-12  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 2 Installation  
Figure 2-22. Sensor Junction Box to Remote Enclosure Connections  
Range Selection Wiring  
To access range selection, connect two wires on the terminal strip as  
shown below. When the switch is closed the device changes to  
Range 2. Opening the switch returns the device to Range 1.  
Figure 2-23. Range Selection Wiring  
Hazardous-Area Enclosures  
Range 1  
1
2
3
4
5
6
7
8
9
20  
19  
18  
17  
16  
15  
14  
13  
12  
RANGE SELECT  
COMON  
Range 2  
10 11  
Figure 2-24. Range Selection Wiring  
IM-78S-B  
2-13  
Chapter 2 Installation  
Series 780S Instruction Manual  
2-14  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 3 Operation  
Chapter 3 Operation  
This chapter covers flow meter operation, programming and instru-  
ment validation procedures. All instructions include directions for  
using either the optional LCD display or the internal Smart electron-  
ics device for programming. If your meter is not equipped with the  
optional display, you will need a good quality digital voltmeter or  
multimeter for programming and validation procedures.  
Flow Meter Start Up  
When applying power to a flow meter equipped with the optional  
LCD display you will see the product name, the software version,  
unit serial number, the range number, the user full scale (UFS), the  
current flow rate and the totalized flow. Any active alarm will flash  
on the screen every few seconds.  
When applying power to a flow meter without the display, the Smart  
electronics on-board single-digit LED flashes the revision number of  
the software in a series of 3 digits followed by the range number.  
The range number continues to flash every three seconds thereafter.  
Record Factory-Set Parameters  
You may view parameters using the optional LCD front panel dis-  
play or by selecting functions on the single-digit LED and viewing  
the meter’s 0-5 VDC output with a digital voltmeter (DVM).  
For meters with the LCD display, use a hand-held magnet or the de-  
vice buttons to select the FUNCTION key. When FUNCTION is  
selected, the display prompts for a password. Select FUNCTION  
again to skip the password to view and record the factory settings.  
To make changes, at the password prompt use the UP arrow until  
the number 11 is displayed. Select FUNCTION again to continue.  
For flow meters without the display, remove the enclosure cover to  
access the Smart electronics device. Connect the DVM as described on  
the following pages and record the factory-set parameters.  
Smart Electronics Device  
Single  
digit LED  
Function  
Inside cover  
Inside cover  
Up  
Down  
Figure 3-1. Smart Electronics Device Locations  
IM-78S-B  
3-1  
Chapter 3 Operation  
Series 780S Instruction Manual  
Using the Smart Electronics Basic Features  
This section covers the basic features of the Smart electronics and in-  
cludes instructions on:  
·
·
·
·
·
entering alarm parameters  
changing the user full scale  
adjusting the K-factor  
adjusting the time response speed  
resetting the totalizer  
Caution!  
Before making any ad-  
justment to the Smart  
electronics device, verify  
the flow meter is not ac-  
tively monitoring or report-  
ing to any master control  
system. Any adjustment  
to the electronics will  
cause direct changes to  
flow control settings.  
To access the meter’s advanced features of zero and span, turn to  
page 3-11. Instrument validation procedures begin on page 3-13.  
Note: when programming the instrument, after 12 seconds of non-  
activity the meter returns to the Run Mode with any new settings imme-  
diately in effect. For units without a display, if the unit “times-out”  
press the FUNCTION button only to resume adjustments.  
Hazardous-Area Enclosure Optional LCD Display  
For units with the optional display, you may program the meter  
without opening the enclosure using the magnetic switches to enter  
the desired system settings.  
Hazardous-Area Enclosures ONLY  
Position magnet at the  
midpoint of the enclosure  
over the desired switch  
LED  
indicator  
DOWN  
UP  
x
FUNCTION  
To activate the magnetic switches for programming:  
1. Position magnet over FUNCTION, UP or DOWN (the LED lamp indicates  
switch activation).  
2. Hold in place until the desired variable is displayed. Remove magnet.  
NOTE: When activating magnetic switches, variables first cycle up or  
down at a slow rate. When holding the magnet in position for longer  
than three seconds, the cycle speed increases to a faster rate.  
Figure 3-2. Magnetic Switch Operation  
3-2  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 3 Operation  
LCD Display Programming Menu  
Start Up  
Screens  
Sierra  
Flow Meter  
Flow meter model  
Software version  
Version  
Meter serial number  
Serial No.  
Run Mode  
LCD Display  
FUNCTIONS  
Current flow rate  
Totalized flow  
Flow  
Total Flow  
Password  
Select  
Current range in use  
User full scale  
Range No.  
UFS  
FUNCTION  
Zero Volts  
Current flow rate  
If an alarm is active,  
will flash  
Flow  
Alarm  
Span Volts  
Zero mA  
For units with the optional front  
panel LCD display, you must  
correctly enter the password to  
change parameters.  
Span mA  
High Alarm  
To view settings, select  
FUNCTION twice, skipping the  
password. To change settings,  
select FUNCTION. At the  
password prompt, use the UP  
arrow until the number 11 is  
displayed. Select FUNCTION  
again to continue.  
Low Alarm  
K-Factor  
Use the UP or DOWN arrows to  
enter new parameters. Select  
FUNCTION to continue.  
User FS  
After 12 seconds of non-activity,  
the settings are saved and the  
meter returns to the Run Mode.  
Time Resp.  
Total Reset?  
IM-78S-B  
3-3  
Chapter 3 Operation  
Series 780S Instruction Manual  
Single-Digit LED Programming Menu  
Run Mode  
FUNCTION  
Assignments  
Software version  
shown in series  
of 3 digits  
Version  
1
2
3
4
5
6
Voltage Zero  
Voltage Span  
Press  
FUNCTION  
Range  
No.  
Range in use  
Press FUNCTION to view or  
change settings.  
Current Zero  
Current Span  
Use the UP or DOWN button  
to enter new parameters.  
Press FUNCTION to continue.  
After 12 seconds of non-activity,  
the settings are saved and the  
meter returns to the Run Mode.  
High Alarm  
Low Alarm  
K-Factor  
7
8
9
User Full Scale  
Time Response  
Delay  
3-4  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 3 Operation  
Entering Alarm Parameters  
Use the High Alarm and Low Alarm function to set or adjust alarm  
trip points. The alarms have a minimum hysteresis of 3% to avoid  
"chattering." When setting a window alarm, the alarm setpoints must  
be at least twice the hysteresis value apart. We suggest at least a 10%  
separation between window alarm setpoints. If you choose not to use  
the high alarm for a specific alarm function, Sierra recommends that  
you set the high alarm at 100% of the user full scale setting which  
creates an “over-range” indicator. Your flow meter will continue to  
indicate flow and generate a signal if the flow is over the maximum  
range, but will not operate within the specified accuracy.  
Caution!  
The flow meter must not be  
reporting or measuring gas  
flow during adjustments.  
Entering Alarms using the LCD Display  
Enter alarms setpoints directly in engineering units.  
1. Select the desired range. Select FUNCTION, enter the pass-  
word. Select FUNCTION again until High Alarm or Low Alarm  
appears on the display.  
2. Use UP or DOWN to enter the high or low alarm setpoint value  
in engineering units.  
3. Select FUNCTION to advance to the next option, or after 12  
seconds of non-activity the meter returns to the Run Mode and  
the new parameters are in effect.  
Entering Alarms using the Single-Digit LED  
When using a DVM to set alarms, the setpoint is a percentage of the  
flow meter’s user full scale.  
VOLTS = (ALARM PERCENT x 5.0)  
If you want to alarm at 25% of user full scale, used in Step 3 below,  
press the UP or DOWN button until 1.25 VDC is present on the  
DVM. If you want to alarm at 75% of user full scale, press the UP  
or DOWN button until 3.75 VDC is present on the DVM.  
1. Set the DVM to voltage mode and connect between Vout+ and  
Vout– on the flow meter terminal block.  
2. Select the desired range. Press the FUNCTION button until a solid  
“5” (high alarm) or solid “6” (low alarm) appears on the LED.  
3. Adjust the UP or DOWN button until the DVM indicates the de-  
sired setpoint voltage as described above.  
4. Press FUNCTION again to advance to the next option, or after  
12 seconds of non-activity the meter returns to the Run Mode  
and the new alarm parameters are in effect.  
IM-78S-B  
3-5  
Chapter 3 Operation  
Series 780S Instruction Manual  
K-Factor Adjustment  
Entering a K-factor adjusts the meter’s output signal without affect-  
ing the factory calibration curve. Use the K-factor calibration offset  
for additional flow profile compensation (the factory includes an ini-  
tial flow profile correction in the calibration curve of the unit).  
Caution!  
The flow meter must not be  
reporting or measuring gas  
flow during adjustments.  
Entering a K-factor using the LCD Display  
A K-factor value of 1.000 means the output value is not affected and  
is the factory default setting. You may enter any number from 0.500  
to 5.000.  
1. Select the desired range. Select FUNCTION, enter the password.  
Select FUNCTION again until K-factor appears on the display.  
2. Use UP or DOWN to enter the desired K-factor value in engi-  
neering units.  
3. Select FUNCTION to advance to the next option, or after 12  
seconds of non-activity the meter returns to the Run Mode and  
the new K-factor is in effect.  
Entering K-factor using the Single-Digit LED  
A K-factor value of 1.000 VDC means the output value is not af-  
fected and is the factory default setting. You may enter any value  
from 0.500 to 5.000 VDC in Step 3 below. If the device indicated  
output is 3.0 VDC and you know it should be 3.8 VDC then you  
could “force” the output to the desired 3.8 VDC by adjusting the K-  
factor to indicate 1.27 VDC (1.27 = 3.8/3.0). Use this formula to  
determine the desired K-factor voltage:  
VOLTS = DESIRED/ INDICATED  
1. Set the DVM to voltage mode and connect between Vout+ and  
Vout– on the flow meter terminal block.  
2. Select the desired range. Press the FUNCTION button until a  
solid “7” appears on the LED.  
3. Adjust the UP or DOWN button until the DVM indicates the de-  
sired K-factor value as described above.  
4. Press FUNCTION to advance to the next option, or after 12  
seconds of non-activity the meter returns to the Run Mode and  
the new K-factor is in effect.  
3-6  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 3 Operation  
User Full Scale Adjustment  
The user full scale (UFS) feature adjusts the flow meter output range  
anywhere within 50% to 100% of the factory full scale (FFS). This  
feature allows you to re-range the voltage or current output of the  
meter to accommodate different flow rates. Note: when entering a  
new user full scale setting for Range 2, it cannot be less than 10% of  
the Range 1 user full scale.  
Caution!  
The flow meter must not be  
reporting or measuring gas  
flow during adjustments.  
Changing the User Full Scale using the LCD Display  
The factory full scale is shown on the flow meter label. If you want a  
UFS equal to the FFS, adjust the display to match the FFS. If you  
want to use 50% of FFS, adjust the display to read 50% of the FFS.  
1. Select the desired range. Select FUNCTION, enter the password.  
Select FUNCTION again until User Full Scale appears on the dis-  
play.  
2. Use UP or DOWN to enter the desired UFS value in engineering  
units.  
3. Select FUNCTION to advance to the next option, or after 12  
seconds of non-activity the meter returns to the Run Mode and  
the new UFS is in effect.  
Changing the User Full Scale using the Single-Digit LED  
If the FFS is set to 11,000 sfpm and UFS is set to output 5.0 VDC,  
or 100%, the flow meter will indicate 5.0 VDC when 11,000 sfpm  
is present on the probe. If you want 6,000 sfpm for UFS, used in  
Step 3 below, adjust the UFS to 6000/11000 or 54.55% of factory  
full scale. Adjust the voltage to 2.73 VDC (2.73 = 5 x .5455). Use  
this formula to determine the desired UFS voltage:  
VOLTS = 5 x User Full Scale / Factory Full Scale  
1. Set the DVM to voltage mode and connect between Vout+ and  
Vout– on the flow meter terminal block.  
2. Select the desired range. Press the FUNCTION button until a  
solid “8” appears on the LED.  
3. Adjust the UP or DOWN button until the DVM indicates the de-  
sired user full scale as described above.  
4. Press FUNCTION to advance to the next option, or after 12  
seconds of non-activity the meter returns to the Run Mode and  
the new UFS is in effect.  
IM-78S-B  
3-7  
Chapter 3 Operation  
Series 780S Instruction Manual  
Time Response Delay Adjustment  
Changing the Time Response Delay using the LCD Display  
1. Select FUNCTION, enter the password. Select FUNCTION  
again until Time Response appears on the display.  
2. Use UP or DOWN to adjust the time response delay from 0.10  
to 7.2 seconds.  
3. Select FUNCTION again to advance to the next option, or after  
12 seconds of non-activity the meter returns to the Run Mode  
and the new time response setting is in effect.  
Changing the Time Response Delay using the Single-Digit LED  
1. Set the DVM to voltage mode and connect between Vout+ and  
Vout– on the flow meter terminal block. Select the desired  
range. Press the FUNCTION button until a solid “9” appears on  
the LED.  
2. Adjust the UP or DOWN button until the DVM indicates the de-  
sired voltage (as shown in the following table).  
Volts  
Indicated  
on DVM  
0.5  
Time  
Response  
(Seconds)  
0.1  
Volts  
Indicated  
on DVM  
1.0  
Time  
Response  
(Seconds)  
0.3  
Volts  
Indicated  
on DVM  
1.5  
Time  
Response  
(Seconds)  
0.5  
Volts  
Indicated  
on DVM  
2.0  
Time  
Response  
(Seconds)  
0.7  
2.5  
1.2  
3.0  
1.8  
3.5  
2.4  
4.0  
3.6  
4.5  
4.8  
5.0  
7.2  
3. Press FUNCTION to advance to the next option, or after 12  
seconds of non-activity the meter returns to the Run Mode and  
the new time response delay setting is in effect.  
3-8  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 3 Operation  
Totalizer Reset  
If your device is equipped with the optional LCD display, reset the  
totalizer using the magnetic switches or device buttons. If you are  
unable to open the flow meter enclosure, use a magnet to reset the  
totalizer as shown below.  
Reset the Totalizer using the LCD Display  
1. Select the desired range. Select FUNCTION, enter the pass-  
word. Select FUNCTION again until Total Reset? appears on  
the display.  
2. Select the UP button and then the DOWN button until the dis-  
play reads “Resetting Totalizer.”  
Reset the Totalizer without Opening the Enclosure  
1. Position a magnet above the enclosure until the display reads  
“Resetting Totalizer.”  
For Hazardous-Area enclosures only: To disable the magnetic reset  
function of the totalizer, remove jumper (J2) from the PCB at the lo-  
cation shown below. (You may not disable the magnetic reset switch  
on NEMA 4X enclosures.)  
IM-78S-B  
3-9  
Chapter 3 Operation  
Series 780S Instruction Manual  
3-10  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 3 Operation  
Using the Smart Electronics Advanced Features  
Zero and span (Function 1 through 4) can be used to validate system  
operation and calibrate the digital to analog signals on the Smart  
electronics device. Additionally, these functions can compensate for  
resistance in long signal cables connected to your data collection or  
indicating system.  
Caution!  
Adjusting zero or span will  
affect meter calibration.  
You must use a certified digital voltmeter to adjust zero and span as  
the voltmeter acts as a standard. We recommend recording the current  
values as shown on the LCD display or DVM before making any  
changes to the zero and span settings. Note: when adjusting zero the  
voltage signal will be driven to 0 VDC and when adjusting span the  
voltage signal will be driven to 5 VDC (or 10 VDC).  
Voltage Zero Adjustment  
If needed, use Zero Volts (Function 1) to adjust the 0-5 VDC output  
to 0.0 VDC, or optional 0-10 VDC to 0.0 VDC.  
1. Set the DVM to voltage mode and connect between Vout+ and  
Vout–.  
2. Select FUNCTION, enter the password (if so equipped). Select  
FUNCTION again until Zero Volts appears on the LCD display  
or a solid “1” appears on the LED. Adjust UP or DOWN until  
the DVM indicates between 0 and .01 VDC (no less than 0.005,  
the Smart electronics device cannot drive negative values).  
3. After 12 seconds of non-activity, the meter returns to the Run  
Mode and the new parameter is in effect.  
Voltage Span Adjustment  
If needed, use Span Volts (Function 2) to adjust the 0-5 VDC output  
to 5.0 VDC, or optional 0-10 VDC to 10 VDC.  
1. Set the DVM to voltage mode and connect between Vout+ and Vout–.  
2. Select FUNCTION, enter the password (if so equipped). Select  
FUNCTION again until Span Volts appears on the LCD display or  
a solid “2” appears on the LED. Adjust UP or DOWN until the  
DVM, indicates between 4.99 and 5.01 VDC. (For 0-10 VDC de-  
vices, the target value is 9.99 to 10.01.)  
3. After 12 seconds of non-activity, the meter returns to the Run  
Mode and the new parameter is in effect.  
IM-78S-B  
3-11  
Chapter 3 Operation  
Series 780S Instruction Manual  
Note: when adjusting zero the current signal will be driven to 4 mA and  
when adjusting span the current signal will be driven to 20 mA. We recom-  
mend recording the current values before making any changes to the current  
zero or span settings.  
Current Zero Adjustment  
If needed, use Zero mA (Function 3) to adjust the 4-20 mA output to  
4.0 mA.  
Caution!  
Adjusting zero or span will  
affect meter calibration.  
1. Disconnect the 4-20 mA (+) loop wire. Set the DVM to current  
mode and connect the positive lead to the wire you just discon-  
nected. Connect the negative lead to the 4-20 mA (–) on the flow  
meter terminal block.  
2. Select FUNCTION, enter the password (if so equipped). Select  
FUNCTION again until Zero mA appears on the LCD display or a  
solid “3” appears on the LED. Adjust UP or DOWN until the DVM  
indicates between 3.95 and 4.05 mA. Set DVM back to voltage  
mode when adjustment is complete.  
3. After 12 seconds of non-activity, the meter returns to the Run  
Mode and the new parameter is in effect.  
Current Span Adjustment  
If needed, use Span mA (Function 4) to adjust the 4-20 mA output  
to 20.0 mA.  
1. Disconnect the 4-20 mA (+) loop wire. Set the DVM to current  
mode and connect the positive lead to the wire you just discon-  
nected. Connect the negative lead to 4-20 (–) on the flow meter  
terminal block.  
2. Select FUNCTION, enter the password (if so equipped). Select  
FUNCTION again until Span mA appears on the LCD display or a  
solid “4” appears on the LED. Adjust UP or DOWN 2 until the  
DVM indicates between 19.95 and 20.05 mA. Set DVM back to  
voltage mode when adjustment is complete.  
3. After 12 seconds of non-activity, the meter returns to the Run  
Mode and the new parameter is in effect.  
3-12  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 3 Operation  
Instrument Validation  
System electronics are verified by injecting a known input value and  
confirming that the flow meter outputs the expected value. This test  
confirms that the microprocessor, analog to digital and digital to  
analog converters, the linearizer and the display are working prop-  
erly. Sensor validation is accomplished by measuring the resistance  
of the velocity and temperature sensors and comparing the results to  
the NIST-traceable calibration data provided with the flow meter.  
These tests confirm that your meter is working correctly and the  
calibration variables did not drift, shift or change values.  
To perform the instrument validation procedures you will need the  
following equipment:  
·
certified digital multimeter with minimum 4 character resolution,  
accuracy of at least ± 0.1% of range  
·
·
Calibration Certificate supplied with the flow meter  
small pot adjusting tool (screwdriver)  
Before beginning the validation procedures, review Figure 3-3 and  
Figure 3-4 to familiarize yourself with the component locations.  
NEMA 4X Enclosures  
J1  
CAL  
RUN  
VR3  
J1 CAL/RUN jumper. Place in the  
CAL position for validation, return to  
RUN position for normal operation.  
Potentiometer VR3  
Hazardous-Area Enclosures  
VR3  
J1  
CAL  
RUN  
Potentiometer VR3  
J1 CAL/RUN jumper. Place in the  
CAL position for validation, return to  
RUN position for normal operation.  
Figure 3-3. Electronics Validation Component Locations  
IM-78S-B  
3-13  
Chapter 3 Operation  
Series 780S Instruction Manual  
Electronics Validation Procedure  
1. Verify the flow meter is off line from any remote communica-  
tions. Make sure the meter’s user full scale setting is the same as  
the factory full scale setting. If not, adjust the user full scale  
value as needed.  
Caution!  
Before beginning this  
procedure, make sure the  
flow meter is not actively  
monitoring or reporting to  
any master control sys-  
tem. Any adjustment to  
the electronics will cause  
direct changes to flow  
control settings.  
2. Locate the Calibration Certificate supplied with the flow meter.  
Record in Table 3-1 the five bridge voltage values, the output  
(VDC or mA) values and the indicated flow values.  
3. Remove power from the flow meter. Remove the cover(s) of the  
flow meter enclosure to access the wiring terminal block and the  
Smart electronics device.  
4. Set the multimeter to the 20 volt range. Connect to BV(+) and  
BV(–) terminals on the flow meter terminal block.  
5. Move the J1 Cal/Run jumper on the Smart electronics device to  
the CAL position. Locate potentiometer VR3 on the Smart elec-  
tronics device. Turn on power to the flow meter.  
6. Adjust potentiometer VR3 until the multimeter matches the first  
bridge voltage point (the value must be ± 0.002 VDC of the  
bridge voltage point).  
7. Record the resulting flow shown on the optional LCD display in  
Table 3-1. If not using a display or if you prefer to validate one  
of the analog output signals, move the multimeter + connection  
to Vout (+). Record the resulting output voltage in Table 3-1. If  
using a 4-20 mA calibrated meter, set the multimeter to read cur-  
rent and connect the meter to read the mA signal in your con-  
nected loop. Record the resulting current output in Table 3-1.  
8. Repeat Step 6 and Step 7 to record the results of the remaining  
four bridge voltage validation points in Table 1. Compare the val-  
ues recorded in Table 3-1. Indicated values must be within the  
flow meter’s stated accuracy shown on the Calibration Certificate.  
9. When data collection is complete, turn off power to the flow me-  
ter. Disconnect the multimeter from the flow meter terminal block.  
10. Place the J1 Cal/Run jumper in the RUN position. Make sure the  
jumper is securely in place before resuming flow meter opera-  
tion. Replace the flow meter cover(s).  
3-14  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 3 Operation  
Calibration Certificate Values  
Validation Test Results  
Flow  
Meter  
Flow  
Meter  
Sample  
Point  
Bridge  
Voltage  
Indicated  
Flow  
Output  
(V or mA)  
Indicated  
Flow  
(LCD)  
Output  
(V or mA)  
Stated  
Stated  
Accuracy  
Accuracy  
0%  
25%  
50%  
75%  
100%  
Table 3-1. Electronics Validation Results  
Sensor Validation Procedure  
1. Locate the Ro temperature (measured resistance at 0°C) value and  
the Alpha value shown on the Calibration Certificate supplied with  
the flow meter.  
2. Turn off power to the flow meter. Allow a 6 minute  
cool-down before continuing.  
Warning!  
Do not power the flow  
meter with the sensor  
jumper disconnected.  
This could cause over-  
heating of the sensors  
and/or damage to the  
electronics.  
3. Remove the cover of the flow meter enclosure to access the sensor  
connection points. Remove the four-position jumper from J5, J6,  
J7 and J8 (see below for location).  
Smart Electronic Device  
NEMA 4X Enclosures  
Terminal Board  
Hazardous-Area Enclosures  
1
2
3
4
5
6
7
8
9
20  
19  
18  
17  
16  
15  
14  
13  
12  
J5 temperature  
J6 temperature  
J7 velocity  
J8 velocity  
Remove jumper,  
measure on LEFT  
ROW of pins  
10 11  
J5 temperature  
J6 temperature  
J7 velocity  
J8 velocity  
Remove jumper, measure  
on RIGHT ROW of pins  
Figure 3-4. Sensor Validation Component Locations  
IM-78S-B  
3-15  
Chapter 3 Operation  
Series 780S Instruction Manual  
4. Set the multimeter to read Ohms in the 2K range. Connect the  
multimeter to the terminals of J5 and J6 (temperature sensor).  
Measure the resistance between J5 and J6 and record the tem-  
perature sensor resistance (in Ohms) in Table 3-2.  
5. Set the multimeter to read in the 200 Ohm range. Connect the mul-  
timeter to terminals of J7 and J8 (velocity sensor). Measure the re-  
sistance between J7 and J8 and record the velocity sensor resis-  
tance (in Ohms) in Table 3-2.  
6. Use the measured resistance values and the Ro and Alpha Ro  
values from the Calibration Certificate to calculate the tempera-  
ture for each sensor as follows:  
R – R  
o
T =  
Alpha x R  
o
Where  
T
= degrees Celsius  
R
R
= measured sensor resistance  
= resistance at 0° C (from the Calibration Certificate)  
o
Alpha = value unique to each sensor (from the Calibration Certificate)  
7. Compare the results recorded in Table 3-2. The sensors are vali-  
dated if they are within 10 degrees Celsius of each other.  
8. Disconnect the multimeter and replace the four-position jumper on  
the sensor terminals. Make sure the jumper is securely in  
place before applying power. Replace cover.  
Temperature Sensor  
Resistance  
T
(from equation)  
Velocity Sensor  
Resistance  
T
(from equation)  
Table 3-2. Sensor Validation Results  
3-16  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 4 Troubleshooting & Repair  
Chapter 4 Troubleshooting and Repair  
Troubleshooting the Flow Meter  
Begin hardware troubleshooting by verifying the following facilities  
issues are correct. These areas impact system operation and must be  
corrected prior to performing any flow meter inspections.  
Warning!  
Before attempting any flow  
meter repair, verify that the  
line is not pressurized.  
1. Verify the incoming power to the flow meter is present and of  
the correct voltage and polarity.  
2. Check the flow meter wiring for correct connections as de-  
scribed in Chapter 2.  
Always remove main power  
before disassembling any  
part of the mass flow meter.  
3. Verify the flow meter is installed with the correct number of up-  
stream pipe diameters as shown on page 2-2.  
4. Verify the flow direction indicator is correctly aligned pointing  
downstream of flow.  
5. Make sure there are no leaks in the line being measured.  
After verifying the factors above, follow the troubleshooting proce-  
dures outlined on the next page. If you need to return the flow meter  
to the factory, see page 4-3 for return shipping instructions.  
Flow Meter Calibration  
Sierra Instruments maintains a fully-equipped calibration laboratory.  
All measuring and test equipment used in the calibration of Sierra  
meters are traceable to NIST standards. Sierra is ISO-9001 regis-  
tered and conforms to the requirements of ANSI/NCSL-Z540 and  
ISO/IEC Guide 25. If the flow body or electronics have been dam-  
aged or you simply want to have the flow meter re-calibrated, con-  
tact the factory for return shipping instructions. Calibration must be  
performed by qualified personnel using NIST-traceable equipment.  
IM-78S-B  
4-1  
Chapter 4 Troubleshooting & Repair  
Series 780S Instruction Manual  
Problem  
Possible Cause  
Solution  
Velocity measurement is  
erratic or fluctuating  
Very erratic or non-uniform flow  
Follow installation requirements shown  
in Chapter 2  
Moisture present in gas flow  
Install a water trap or filter upstream of  
the flow meter sensor  
Flow conditioning plates are not  
upstream of the sensor  
Correct flow meter orientation  
Sensor component broken  
Return to factory for replacement  
Return to factory for evaluation  
Malfunction in system  
electronics  
Ground loop  
Check wiring, see Chapter 2  
Velocity measurement  
seems too high or low  
Sensor assembly not aligned  
correctly to flow  
Correct alignment with the flow indicator  
pointing downstream in the direction of  
flow  
Flow conditioning plates are not  
upstream of the sensor  
Correct flow meter orientation  
No response to flow from No power  
Turn on power to the flow meter  
sensor assembly  
Low flow cutoff setting too high  
Correct low flow cutoff programming  
using the Smart Interface software.  
Flow rate below meter’s minimum  
flow rating  
Contact factory for instructions  
Flow has exceeded the maximum  
range of the flow meter  
Set the user full scale to equal the fac-  
tory full scale  
Reduce flow below the maximum range  
shown on the meter’s nameplate or con-  
tact the factory for re-calibration advice  
Sensor failure  
Return to factory for evaluation  
Return to factory for evaluation  
Printed circuit assembly defective  
4-2  
IM-78S-B  
Series 780S Instruction Manual  
Chapter 4 Troubleshooting & Repair  
Returning Equipment to Factory  
Before returning any mass flow meter to the factory, you must re-  
quest and complete a Sierra Calibration/Repair Data Sheet. To obtain  
the data sheet contact Customer Service at:  
(800) 866-0200 or (831) 373-0200 in the US  
or +31(0)20-6145810 in Europe.  
Return shipments to:  
USA Headquarters  
Sierra Instruments Service Department  
5 Harris Court, Building W  
Monterey, CA 93940  
European Headquarters  
Sierra Instruments b.v. Service Department  
Bolstoen 30A  
1046 AV Amsterdam, The Netherlands  
When returning a component, make sure to include the completed  
Calibration/Repair Data Sheet with the shipment.  
IM-78S-B  
4-3  
Chapter 4 Troubleshooting & Repair  
Series 780S Instruction Manual  
4-4  
IM-78S-B  
Series 780S Instruction Manual  
Appendix A Specifications  
Appendix A Product Specifications  
Performance Specifications  
Accuracy  
± 2% of reading from 10 to 100% of calibrated range  
± 0.5% of full scale below 10% of calibrated range  
± 0.2% of full scale  
Repeatability  
Temperature Coefficient  
± 0.02% of reading per °F within ± 50°F of customer specified conditions  
± 0.03% of reading per °F within ± 50°F to 100°F of customer specified conditions  
±0.04% of reading per °C within ± 25°C of customer specified conditions  
±0.06% of reading per °C within ± 25°C to 50°C of customer specified conditions  
Pressure Coefficient  
Response Time  
Negligible when within ± 50 psig (± 3.4 barg) of customer specified conditions  
One second to 63% of final velocity value  
Operating Specifications  
Gases  
Most gases compatible with 316L stainless steel (consult factory)  
Mass Flow Rates  
Air Flow Ranges(1)  
Minimum  
Pipe Size  
Maximum(2) (3)  
(nm3/hr)  
scfm  
0–0.5  
0–2  
(nm3/hr)  
(0–0.7)  
(0–3.0)  
(0–5.9)  
(0–8.9)  
(0–22)  
scfm  
0–9  
1/4-inch  
1/2-inch  
3/4-inch  
1-inch  
(0–14)  
(0–60)  
0–40  
0–4  
0–75  
(0–120)  
(0–180)  
(0–440)  
(0–680)  
(0–1500)  
(0–2700)  
(0–5900)  
(0–10,000)  
0–6  
0–120  
0–280  
0–470  
0–1000  
0–1800  
0–4000  
0–7000  
1 1/2-inch  
2-inch  
0–15  
0–23  
0–50  
0–90  
0–200  
0–350  
(0–33)  
3-inch  
(0–74)  
4-inch  
(0–130)  
(0–300)  
(0–520)  
6-inch  
8-inch  
Notes:  
(1) Flow rates for air and nitrogen. Standard conditions: 70°F  
and one atmosphere for scfm; 0°C and one atmosphere for  
nm3/hr. Consult factory for other gases.  
(2) Higher flow ranges available, consult factory.  
(3) Maximum flow rates are limited for hazardous area  
and high temperature versions, consult factory.  
Dual Calibration  
Gas Pressure  
User-selectable dual ranges or two different gases  
150 lb flange or PN16 DIN (–40° F to 100° F): 230 psig (15.9 barg) maximum  
150 lb flange or PN16 DIN (250° F): 185 psig (12.8 barg) maximum  
150 lb flange or PN16 DIN (450° F): 155 psig (10.7 barg) maximum  
NPT (–40° F to 450° F): 500 psig (34 barg) maximum, 5 to 150 psig  
(0.3 barg to 10 barg) optimum  
Gas & Ambient Temperature Gas...............–40° to 250°F (–40° to 120°C) Optional –40° F to 450° F  
(–40° C to 230° C) not available on 1/4 and 1/2-inch flow bodies  
Ambient........–5° to 120°F (–20° to 50°C)  
IM-78S-B  
A-1  
Appendix A Specifications  
Series 780S Instruction Manual  
Leak Integrity  
1 X 10–4 atm cc/sec of helium maximum  
Power Requirements  
18 to 30 VDC (regulated), 625 mA maximum  
100 to 240 VAC , 50/60 Hz, 15 watts maximum*  
*not available on NEMA 4X enclosures  
Output Signal  
Alarms  
Linear 0-5 VDC or 0-10 VDC proportional to mass flow rate, 1000 Ohms mini-  
mum load resistance, or Linear 4-20 mA proportional to mass flow rate, 700  
Ohms maximum resistance (power supply dependent), optically isolated  
User-adjustable low, high or window alarms  
Deadband adjustable with Smart Interface™ software  
Relay rating...............Maximum 42 VAC or 42 VDC, 140 mA  
Displays  
Alphanumeric 2 x 12 digit backlit LCD  
Adjustable variables via on-board membrane buttons or with Smart Interface™ software  
Adjustable variables...............Full scale adjustment (50 to 100%)  
Time response (0.1 to 7.2 seconds)  
Correction factor setting (0.5 to 5)  
Zero and span adjustments  
Totalizer  
Software  
Eight digits (99,999,999) in engineering units  
Smart Interface Windows™-based software, minimum 8 MB of RAM,  
preferred 16 MB of RAM, RS-232 communication  
Physical Specifications  
Wetted Materials  
316L stainless steel, Schedule 40 pipe flow body, Carbon steel flow bodies  
available in some sizes  
Enclosure  
Hazardous-Area enclosure (IP67) and NEMA 4X (IP65) powder-coated cast aluminum  
Electrical Connections  
Two 3/4 inch NPT  
One 1/2 inch NPT  
Hazardous-Area enclosure (IP67)  
NEMA 4X enclosure (IP65)  
Certifications*  
CE (all enclosures)  
CSA (Explosion proof for Class I, Division 1, Groups B, C, D)  
EEx (EEx dIIC T6...T2) Cenelec  
FM (Explosion proof for Class I, Division 1, Groups B, C, D)  
*Certifications pending, contact factory  
A-2  
IM-78S-B  

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