NI USB-443x Calibration Procedure
10
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9.
Compare the calculated value to the DC coupled gain accuracy limits.
If verifying an NI USB-4431, compare the calculated value to the appropriate limits in Table 8. If
verifying an NI USB-4432, compare the calculated value to the appropriate limits in Table 9.
10. Repeat steps 1 through 9 for each analog input channel that you want to verify. Connect the output
of the calibrator to the channel being verified in step 1. In step 3, replace ai
x
in the physical channel
parameter with the channel being verified.
NI recommends that you verify each channel, but you can save time by verifying only the channels
used in your application.
Analog Output Performance Verification
This section verifies the analog output (AO) performance of the NI USB-4431 device. Refer to the
NI USB-443x Specifications
for the performance specifications.
AO Offset Verification for the NI USB-4431 Device
Complete the following steps to verify the AO offset:
1.
Connect channel AO 0 on the device to the input of the multimeter.
2.
Create and configure an AO voltage task on the NI USB-4431 as shown in Table 10.
3.
Create an array of length 96,000. Set every element in the array to a value of 0.0. Write the array
to the AO task.
4.
Start the AO task. The AO channel will output 0 V as long as the task is running because
regeneration mode is enabled and the task is configured to generate samples continuously.
5.
Wait 100 ms. This compensates for the filter delay of the analog output channel.
6.
Measure the DC voltage of channel AO 0 on the device using the lowest voltage range of the
multimeter that can measure approximately 100 mV. Record the measured offset, as it will be used
in the
AO Gain Verification for the NI USB-4431 Device
procedure.
Table 10.
AO Offset Verification Configuration for NI USB-4431
Configuration
Value
Minimum value
–3.5
Maximum value
3.5
Terminal configuration
Pseudodifferential
Acquisition mode
Continuous samples
Rate
96000.0
Samples per channel
96,000
Regeneration mode
Allow regeneration
Physical channel
Dev_name/ao0
*
*
Dev_name is the name shown for the NI USB-4431 in MAX.
