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NI PXI-4130 Calibration Procedure
Verifying Voltage Measurement Accuracy
To verify the voltage measurement accuracy of the NI 4130, compare a set of measurements
taken by the NI 4130 to measurements of the actual voltage at the output by a DMM. Refer to
the following figure for the necessary connections.
Figure 2.
Voltage Verification Connection Diagram
Table 6 lists the voltage test points that you must request for each channel and then measure with
both the DMM and the NI 4130 to complete verification. Take voltage measurements using the
DMM at each test point, and then take voltage measurements using the NI 4130 at each test point
and compare the two values. Calculate the upper and lower test limits using the gain and offset
listed in the
Test Limit
column for the iteration of channel
x
in Table 6. Table 6 lists tolerances
instead of absolute limits because the test limit is based on the output of the DMM and must be
calculated by the user. Each limit is calculated by adding a percentage of the DMM measurement
and an offset voltage. Verify that the difference between the NI 4130 measurement and the
DMM measurement falls between the calculated limits. If the measurement error is outside the
test limit, adjust the NI 4130.
When taking measurements with the NI 4130, set the Samples to Average property to
300
.
To ensure the system has had adequate time to settle, wait one second after requesting a new
current before taking a measurement with the DMM. When you verify all iterations per channel,
this part of the verification is complete.
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