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NI PXIe-4464 Calibration Procedure
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© National Instruments
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9
4.
If the coupling changes from DC to AC (for example, on the first gain verification point
tested), commit the configuration using the DAQmx Control Task VI and wait 5 seconds
for the input to settle. Subsequent gain verification points, which do not change the
coupling, do not require a delay.
5.
Start the task.
6.
Acquire readings with the NI PXIe-4464.
7.
Calculate the RMS amplitude of the acquired fundamental harmonic. Compare this
amplitude to the appropriate voltage limits in Table 5. The calculated amplitude is used to
verify the gain accuracy of analog input channel 0 at the -20 dB gain setting.
As an example, you can use the Extract Single Tone Information VI to help calculate RMS.
Note that the output of this VI is peak amplitude, and you must divide the result by
√
2 to
convert to RMS.
8.
Stop and clear the task.
9.
Repeat steps 2 through 8 for each gain setting of the device. When performing step 2,
configure the calibrator output to the amplitude and frequency indicated for the gain range
to be verified. When performing step 3, set the
gain
1
parameter to -10, 0, 10, 20, and 30 as
required.
10. Repeat steps 1 through 9 for all input channels of the device. In step 1, connect the output
of the calibrator to the channel being verified. In step 3, replace
ai0
in the
physical
channel
parameter with the channel being verified.
AI Gain Flatness Verification
Note
This performance characteristic is not affected by adjustment. Consequently,
reverification after adjustment is not necessary.
Note
DC-coupled gain flatness is inherently better than AC-coupled gain flatness,
specifically at low frequencies. Consequently, the verification of AC-coupled gain
flatness covers both configurations.
1
Refer to Table 3 for the maximum and minimum voltages to specify to ensure the specified gain range is
used on the module.