National Instruments RM-4339 Manual

CALIBRATION PROCEDURE
RM-4339
Rack-Mount Accessory Universal Bridge
This document contains the verification procedures for the National Instruments RM-4339. For
more information about calibration solutions, visit ni.com/calibration.
Contents
Software.................................................................................................................................... 1
Documentation.......................................................................................................................... 2
Test Equipment......................................................................................................................... 3
Connecting the Calibrator to the RM-4339 ...................................................................... 4
Test Conditions......................................................................................................................... 4
Initial Setup............................................................................................................................... 5
Verification ............................................................................................................................... 5
SCA Shunt Calibration Resistance Accuracy Verification .............................................. 5
Offset Voltage Verification .............................................................................................. 7
Quarter-Bridge Shunt Calibration Accuracy Verification................................................ 9
Specifications............................................................................................................................ 12
World Wide Support and Services ........................................................................................... 13
Software
Calibrating the NI RM-4339 requires the installation of NI-DAQmx on the calibration system.
Driver support for the RM-4339 was first available in NI-DAQmx 14.5. For the list of devices
supported by a specific release, refer to the NI-DAQmx Readme, available on the
version-specific download page or installation media.
You can download NI-DAQmx from ni.com/downloads. NI-DAQmx supports numerous
programming languages, including LabVIEW, LabWindows™/CVI™, C/C++, C#, and Visual
Basic .NET. When you install NI-DAQmx, you only need to install support for the application
software that you intend to use.
ni.com/manuals
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2|ni.com |RM-4339 Calibration Procedure
Documentation
Consult the following documents for information about the RM-4339, NI-DAQmx, and your
application software. All documents are available on ni.com and help files install with the
software.
NI PXIe-4339 and RM-4339 User Guide and Terminal Block Specifications
NI-DAQmx installation, hardware setup, and RM-4339 specifications.
NI PXIe-4339 and TB-4339/B/C Installation Guide and Terminal Block
Specifications
NI-DAQmx installation and hardware setup.
NIPXIe-4339 User Manual
NI PXIe-4339 specific information.
NI PXIe-4339 Specifications
NI PXIe-4339 specifications and calibration interval.
NI-DAQmx Readme
Operating system and application software support in NI-DAQmx.
NI DAQmx Help
Information about creating applications that use the NI-DAQmx driver.
LabVIEW Help
LabVIEW programming concepts and reference information about NI-DAQmx
VIs and functions.
NI-DAQmx C Reference Help
Reference information for NI-DAQmx C functions and NI-DAQmx C properties.
NI-DAQmx .NET Help Support for Visual Studio
Reference information for NI-DAQmx .NET methods and NI-DAQmx .NET
properties, key concepts, and a C enum to .NET enum mapping table.

RM-4339 Calibration Procedure |© National Instruments |3
Test Equipment
Table 1 lists the equipment recommended for the performance verification procedures. If the
recommended equipment is not available, select a substitute using the requirements listed in
Table 1.
Table 1. Recommended Equipment
Equipment
Recommended
Model Requirements
Calibrator Fluke 5520A If this instrument is unavailable, use a
calibrator that can provide resistance
values in the range of 120 to 1 kwith
0.01 resolution, and an accuracy of
90 ppm or better, and can sink 15 mA on
the 120 setting, 8 mA on the 350 
setting, and 3 mA on the 1 ksetting.
Ohm Meter NI PXI-4070 If this instrument is unavailable, use a
6 ½ digit DMM with 2-wire resistance
measurement capability and resistance
accuracy of 80 ppm or better of reading
+6 ppm of range for the 100 krange.
8-Channel
Universal-Bridge Input
Module
NI PXIe-4339 —
Terminal Block
Connection Accessory
TB-4339/B/C —
PXI Express Chassis NI PXIe-1062Q —
Accessory Cable SH96-96-2 The SH96-96-2 is available in 1 meter,
3 meter and 5 meter lengths. Any of these
cable lengths can be used.
RJ50 to Pigtail Cable (8) NI P/N: 195950-02 An RJ50 cable with a cable wire
resistance < 0.2 with better than 10%
resistance mismatch between individual
wires.

4|ni.com |RM-4339 Calibration Procedure
Connecting the Calibrator to the RM-4339
Caution Always have the NI PXI Express chassis powered off when inserting a
module into the chassis.
Refer to the specific verification procedure section for information describing the required
connections.
Note To minimize the number of verification connection changes, the connections
for SCA shunt calibration resistance verification and quarter-bridge shunt calibration
verification can be made simultaneously.
The RM-4339 provides support for up to three NI PXIe-4339 modules. The 96-pin DIN
connectors used to connect the NI PXIe-4339 to the RM-4339 through the SH96-96-2 cable are
located on the rear of the RM-4339 and are labeled A, B, and C. To fully verify the RM-4339,
each of the verification procedures in this document must be conducted for each position A, B,
and C. Refer to the NI PXIe-4339 and RM-4339 User Guide and Terminal Block Specifications
for information about how to install and use the RM-4339.
Test Conditions
The following setup and environmental conditions are required to ensure the RM-4339 meets
published specifications.
• Keep connections to the RM-4339 as short as possible. Long cables and wires act as
antennas, picking up extra noise that can affect measurements.
• Verify that all connections are secure.
• Shielded and twisted pair copper wire is recommended for all cable connections to help
prevent external noise sources from coupling into the measurements.
• Maintain an ambient temperature of 23 °C ± 5 °C. The offset voltage verification procedure
requires less than 1 °C of ambient temperature variation over the duration of the test. Refer
to Offset Voltage Verification procedure for more details.
• Keep relative humidity below 80%.
• Allow a warm-up time for each of the instruments used in this procedure according to the
specific instruments operating instructions.
• Ensure that the PXI Express chassis fan speed is set to HIGH, that the fan filters are clean,
and that the empty slots contain filler panels. For more information, refer to the Maintain
Forced-Air Cooling Note to Users document available at ni.com/manuals.

RM-4339 Calibration Procedure |© National Instruments |5
Initial Setup
Refer to the NI PXIe-4339 and RM-4339 User Guide and Terminal Block Specifications for
information about how to install the software and hardware, and how to configure the device in
Measurement & Automation Explorer (MAX).
Note When a device is configured with MAX, it is assigned a device identifier.
Each function call uses this identifier to determine which DAQ device to verify,
or verify and adjust. In this document, Dev1 was used for inputs that required a
device identifier.
Verification
The following performance verification procedures describe the sequence of operation and
provides test points required to verify the RM-4339. The verification procedures assume that
adequate traceable uncertainties are available for the calibration references.
SCA Shunt Calibration Resistance Accuracy Verification
This section provides instructions for verifying the RM-4339 SCA shunt calibration resistance
accuracy. Throughout the shunt calibration resistance accuracy verification, use Table 3 to
determine if the RM-4339 is operating within its specified range.
Complete the following steps to test the accuracy of the RM-4339 SCA shunt calibration
resistances:
1. Plug an RJ50 cable into the RM-4339s RJ50 connector of the channel you want to
verify. Connect SCA (pin 1) of the RJ50 cable to the DMM HI input and connect SCA
(pin 10) of the RJ50 cable to the DMM LO input as shown in Figure 1.
Figure 1. RJ50 to DMM Connections
2. Configure the DMM for a 2-wire resistance measurement.
DMM
RJ50 Connector
on the RM-4339
HI
LO
SCA (pin1)
SCA (pin 10)
ΩInput

6|ni.com |RM-4339 Calibration Procedure
3. Create a task to enable SCA shunt calibration.
a. Create and configure an AI Bridge (V/V) measurement according to the values found
in Table 2.
b. Enable the SCA shunt calibration circuit using the following parameters:
Property Node: DAQmx Channel
AI.Bridge.ShuntCal.Select: A
AI.Bridge.ShuntCalASrc: Built-In
AI.Bridge.ShuntCal.ShuntCalAResistance: 100 k
AI.Bridge.ShuntCal.Enable: True
Note These properties are located at Analog Input»General Properties»Signal
Conditioning»Bridge»Shunt Cal.
c. Commit the task by calling DAQmx Control Task with the following parameter:
Action: Commit
4. Take a resistance measurement from the DMM and record the result.
5. Compare the result from step 4 to the Upper Limit and Lower Limit values in Table 3. If
the result is between these values, the module passes the test.
6. Clear the task by calling DAQmx Clear Task.
Table 2. AI Bridge Configuration
Configuration Value
Channel Name Dev1/aix,where xrefers to the channel number.
Measurement Type AI Bridge (V/V)
Voltage Excitation Source Internal
Voltage Excitation Value 3.3
Maximum Value 0.01
Minimum Value -0.01
Units V/V
Bridge Configuration Full
Sample Mode Finite Samples
Sample Clock Rate 100
Samples per Channel 100

RM-4339 Calibration Procedure |© National Instruments |7
7. Repeat steps 1 through 6 for each channel you want to verify.
8. Disconnect the DMM from the module.
Offset Voltage Verification
The offset voltage verification uses the NI PXIe-4339 to measure the offset voltage of the
RM-4339. Prior to measuring the offset voltage of the RM-4339, an offset characterization is
performed on the NI PXIe-4339 using a TB-4339/B/C to provide an electrical short on the input
of the NI PXIe-4339. The temperature variation of the environment should be kept within 1 °C
between measurement of the offset error of the NI PXIe-4339 and the offset measurement of the
RM-4339.
Complete the following steps to verify the offset voltage:
1. Make the following connections:
a. On the TB-4339/B/C, short the AI+ and AI- of all the channels to AIGND.
Note Refer to the NI PXIe-4339 and TB-4339/B/C Installation Guide and Terminal
Block Specifications for the pin assignments and signal names.
b. Connect the female end of the SH96-96-2 cable to the NI PXIe-4339.
c. Connect the TB-4339/B/C to the male end of the SH96-96-2 cable.
Table 3. SCA Shunt Calibration Resistance Accuracy Limits
Nominal Value ()Lower Limit ()Upper Limit ()
100,000 99,900 100,100

8|ni.com |RM-4339 Calibration Procedure
2. Acquire voltage measurements from all channels with the NI PXIe-4339.
a. Create and configure an AI voltage measurement according to the values found in
Table 4.
b. Start the task by calling DAQmx Start Task.
c. Average the readings that you acquired and record the vales as VoffsetPXIe-4339Chx,
where xis the channel number.
d. Clear the task by calling DAQmx Clear Task.
3. Remove the TB-4339/B/C from the SH96-96-2 cable and connect the SH96-96-2 cable to
the 96-pin connector on the back of the RM-4339.
4. Connect an RJ50 cable to each channel with AI+ (pin 2) and AI- (pin 3) connected to
T- (pin 9).
5. Acquire voltage measurements from all channels with the NI PXIe-4339.
a. Create and configure an AI voltage measurement according to the values found in
Table 4.
b. Start the task by calling DAQmx Start Task.
c. Average the readings that you acquired and subtract VoffsetPXIe-4339Chx from the
average values for each channel.
Table 4. AI Voltage Mode Setup
Configuration Value
Channel Name Dev1/ai0:7
Measurement Type AI Voltage
Maximum Value 0.01
Minimum Value -0.01
Units Vo l t s
Input Terminal Configuration Default
Sample Mode Finite Samples
Sample Clock Rate 100
Samples per Channel 100

RM-4339 Calibration Procedure |© National Instruments |9
d. Compare the values obtained in step c with those in Table 5.
e. Clear the task by calling DAQmx Clear Task.
Quarter-Bridge Shunt Calibration Accuracy Verification
Complete the following procedure to verify the quarter-bridge shunt calibration accuracy of the
RM-4339:
1. Set the calibrator to standby mode (STBY).
2. Using an RJ50 cable connect the calibrator to the channel of the RM-4339 you want to
verify.
Note Only one channel can be connected to the calibrator at a time.
a. Connect EX+ (pin 6) to HI, connect QTR (pin 5) to LO and connect AI+ (pin 2)
to LO as shown in Figure 2.
Figure 2. RJ50 to Calibrator Connections
b. QTR and AI+ must be connected together at the calibrator. The EX+ lead wire and the
QTR lead wire must be the same length.
3. Set the calibrator output to 120 , 350 , or 1000 depending on the quarter-bridge
configuration you want to verify. This must match the configuration setting made in step 6 a.
4. Set the calibrator output for compensation off (COMP off).
5. Set the calibrator to operate mode (OPR) to enable the output.
Table 5. Offset Voltage Accuracy Limits
Range (V)
Test Point (V) Lower Limit (V) Upper Limit (V)Minimum Maximum
-0.1 0.1 0-0.000010 0.000010
Calibrator
RJ50 Connector
on the RM-4339
HI
LO
EX+ (pin 6)
AI+ (pin 2)
QTR/RS-
(pin 5)
Normal
ΩOutput

10 |ni.com |RM-4339 Calibration Procedure
6. Acquire an AI Bridge (V/V) measurement with shunt calibration disabled.
a. Create and configure an AI Bridge (V/V) channel according to the values found in
Table 6.
b. Disable the SCB shunt calibration circuit using the following parameters:
Property Node: DAQmx Channel
AI.Bridge.ShuntCal.Enable: False
c. Commit the task by calling DAQmx Control Task with the following parameter:
Action: Commit
d. Wait 5 seconds to allow the circuitry to stabilize. If the calibrator requires more than
a 5 second wait time, use the wait time required by the calibrator.
e. Start the task by calling DAQmx Start Task.
f. Average the readings that you acquired and record the values as ResultSCD.
g. Clear the task by calling DAQmx Clear Task.
7. Acquire an AI Bridge (V/V) measurement with shunt calibration enabled.
a. Create a task.
b. Create and configure an AI Bridge (V/V) channel according to the values found in
Table 6.
Table 6. AI Bridge (V/V) Mode Setup
Configuration Value
Channel Name Dev1/aix, where xrefers to the channel number
Measurement Type AI Bridge (V/V)
Bridge Configuration Quarter
Nominal Bridge Resistance 120 , 350 , 1000 
Voltage Excitation Source Internal
Voltage Excitation Value 3.3 V for 120 configuration, 5 V for 350 and 1 k
configurations
Maximum Value 0.01
Minimum Value -0.01
Units V/V
Sample Mode Finite Samples
Sample Clock Rate 100
Samples per Channel 100
* Use the bridge resistance value that corresponds to the configuration being verified.

RM-4339 Calibration Procedure |© National Instruments |11
c. Enable the SCB shunt calibration circuit using the following parameters:
Property Node: DAQmx Channel
AI.Bridge.ShuntCal.Select: B
AI.Bridge.ShuntCal.ShuntCalBResistance: 50k for 120 , 100k for 350 and 1 k
AI.Bridge.ShuntCal.Enable: True
d. Start the task by calling DAQmx Start Task.
e. Average the readings that you acquired and record the values as ResultSCE.
f. Clear the task by calling DAQmx Clear Task.
8. Calculate the shunt calibration scaling factor as follows:
SCalScaleFactor =SCalExp/(ResultSCE - ResultSCD)
where
SCalExp is the expected shunt calibration deflection, given in the following, for each
of the supported quarter-bridge completion values.
SCalExp = -0.00059928 for 120 
SCalExp = -0.00087347 for 350 
SCalExp = -0.00248756 for 1 k
For reference, the calculation for the expected shunt calibration deflection is
given by the following equation:
where
Req is the equivalent parallel resistance of the quarter-bridge and shunt
calibration resistors.
Rqtr is the resistance of the quarter-bridge completion resistor.
9. Set the calibrator output to the value of the Calibrator Output indicated in Table 7 for the
quarter-bridge configuration that is being verified.
10. Acquire an AI Bridge (V/V) measurement.
a. Create a task.
b. Create and configure an AI Bridge (V/V) channel according to the values found in
Table 6.
c. Disable the SCB shunt calibration circuit using the following parameters:
Property Node: DAQmx Channel
AI.Bridge.ShuntCal.Enable: False
d. Start the task by calling DAQmx Start Task.
e. Average the readings that you acquired, subtract ResultSCD from the averaged result,
and record the values as UnscaledOffsetComp.
SCalExp Req
Req Rqtr +
-------------------------0.5–=

12 |ni.com |RM-4339 Calibration Procedure
f. Multiply UnscaledOffsetComp by SCalScaleFactor that was calculated in step 8 and
record the value as ScaledOffsetComp.
g. Compare ScaledOffsetComp to the Upper and Lower Limits from Table 7 for the
quarter-bridge configuration that is being verified. If the results are within the Upper
and Lower Limits the device passes the verification test.
h. Clear the task by calling DAQmx Clear Task.
11. Repeat steps 3 through 10 for each quarter-bridge configuration.
12. Repeat steps 1 through 11 for each channel.
13. Set the calibrator to standby mode (STBY).
14. Disconnect the calibrator from the device.
Note Test limits in this document are based upon the March 2015 edition of the
NI PXIe-4339 and RM-4339 User Guide and Terminal Block Specifications. Refer to
the most recent NI PXIe-4339 and RM-4339 User Guide and Terminal Block
Specifications online at ni.com/manuals.
If the device is not operating within the specified values, refer to the World Wide Support and
Services section for assistance in returning the device to NI.
Specifications
Refer to the NI PXIe-4339 and RM-4339 User Guide and Terminal Block Specifications for
detailed specification information.
Table 7. Quarter-Bridge Shunt Calibration Accuracy Limits
Quarter-Bridge
Completion (
Calibrator
Output ()
Nominal Value
(V/V)
Lower Limit
(V/V)
Upper Limit
(V/V)
120 116.0 0.0084746 0.0084449 0.0085042
350 338.4 0.0084253 0.0084043 0.0084464
1000 966.8 0.0084401 0.0084190 0.0084612

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