National Instruments NI 4495, Процедура калибровки, Страница: 7 / 22

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NI 449
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Calibration Procedure
Analog Input Performance Verification
This section verifies the analog input (AI) performance of all NI 449x devices. Refer to the
NI 449x Specifications for the number of channels and performance specifications.
AI Offset Verification
Complete the following steps to verify the AI offset:
1. Connect a BNC shorting cap to channel AI 0 on the device and wait 5 seconds for the inputs
to settle.
2. Create and configure an AI voltage task on the NI 449x as shown in Table 2.
3. If verifying an NI 4492/4497/4499 and the coupling changes from DC to AC, commit the
configuration using the DAQmx Control Task VI and wait 5 seconds for the input to settle.
4. Start the task.
5. Acquire readings with the NI 449x.
6. Stop and clear the task.
7. Average all of the acquired samples.
Table 2. NI 449x AI Offset Verification Configuration
Configuration Value
Minimum value –10.0
Maximum value 10.0
Terminal configuration Pseudodifferential
Acquisition mode Finite number of samples
Rate 204,800.0
Samples per channel 102,400
Gain 0 (dB)
Physical channel Dev_name/ai0
*
Coupling NI 4492: AC or DC
NI 4495: DC
NI 4496: AC
NI 4497: AC or DC
NI 4498: AC
NI 4499: AC or DC
*
Dev_name is the name shown for the NI 449x in MAX.