NI 9235/9236 Calibration Procedure
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6.
Set the calibrator resistance output to 120
Ω
for the NI 9235 or 350
Ω
for the NI 9236.
7.
Set the calibrator to operate mode (OPR).
8.
Wait one minute to allow the bridge elements formed by the calibrator
and the module completion resistor to thermally stabilize.
Verification Procedures
Verification determines how well the device is meeting its specifications.
By completing this procedure, you can see how the device has drifted over
time, which helps you determine the appropriate calibration interval for
your application. The NI 9235/9236 has eight independent analog input
channels. You can conduct verification on any or all of them, depending
upon your desired test coverage.
You can verify the following for NI 9235/9236 modules:
•
measurement accuracy
•
shunt calibration accuracy
•
excitation voltage
Measurement Accuracy Verification
Complete the following steps to test the measurement accuracy of the
device:
1.
Zero the calibrator with the ohms-only zero (OHMS ZERO) operation.
Refer to the calibrator documentation for more information about
zeroing the calibrator.
2.
Set the calibrator output for two-wire compensation (COMP 2-wire).
This automatically compensates for the lead wire resistance between
the HI terminal of the calibrator and the EXC terminal of the module.
3.
Connect the calibrator to the channel you want to verify, as explained
in the
Connecting the Calibrator to the Module
section.
4.
Set the calibrator resistance output to a Calibrator Output value
indicated in Table 5 for the NI 9235 and Table 6 for the NI 9236,
beginning with the 0 V/V nominal value.