NI 449
x
Calibration Procedure | © National Instruments | 13
3.
Create and configure an AI voltage task on the NI 4492/4495/4497/4499 as shown in
Table 16.
4.
Start the task.
5.
Acquire readings with the NI 4492/4495/4497/4499.
6.
Stop and clear the task.
7.
Average all of the acquired samples. Compare the result to the appropriate limits in
Table 15, adjusted for any deviation of the measured voltage source value from the nominal
value listed. For example, if the measured value was 5 mV higher than the nominal value,
adjust all of the associated limits higher by the same 5 mV. The calculated average is used
to verify the DC coupled gain accuracy of channel AI 0 at the 0 dB gain setting, at the
204.8 kS/s sample rate.
Table 15.
AI DC Coupled Gain Accuracy Limits
Device
Gain
Voltage Source
Output (nominal)
As Found
Test Limit
As Left
Test Limit
Amplitude (V)
Min (V)
Max (V)
Min (V)
Max (V)
0 dB
8.5
8.457
8.543
8.478
8.522
10 dB
2.686
2.672
2.700
2.679
2.693
20 dB
0.85
0.8452
0.8548
0.8476
0.8524
30 dB
0.2686
0.2668
0.2704
0.2677
0.2695
Table 16.
NI 4492/4495/4497/4499 AI DC Coupled Gain Accuracy 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
DC
*
Dev_name is the name shown for the NI 449x in MAX.
