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NI 449
x
Calibration Procedure
If verifying an NI 4492/4497/4499, separately verify AC and DC coupling for each
supported gain setting including 0 dB at sample rates of 102.4 kS/s and 204.8 kS/s. Refer
to Table 6 for the gain settings supported by supported by NI 449x devices.
9.
Repeat steps 1 through 8 for all input channels on the device. Connect the BNC shorting
cap to the channel being verified in step 1. In step 2, replace
ai0
in the physical channel
parameter with the channel being verified.
AI AC Coupled Gain Accuracy Verification
Note
This section does not apply to the NI 4495. Skip this section if verifying an
NI 4495.
Complete the following steps to verify AC coupled gain accuracy:
1.
Connect the output of the calibrator to channel AI 0 on the device.
2.
If verifying an NI 4496/4498, configure the calibrator to generate a tone with the amplitude
and frequency listed in the 0 dB gain row of Table 7. Wait 5 seconds for the inputs to settle.
If verifying an NI 4492/4497/4499, configure the calibrator to generate a tone with the
amplitude and frequency listed in the 0 dB gain row of Table 8. Wait 5 seconds for the
inputs to settle.
Table 7.
AI AC Coupled Gain Accuracy Limits for NI 4496/4498
Device
Gain
Calibrator
Output
As Found
Test Limit
As Left
Test Limit
Amplitude
(V
rms
)
Frequency
(Hz)
Min
(V
rms
)
Max
(V
rms
)
Min
(V
rms
)
Max
(V
rms
)
0 dB
6.36
1000
6.287
6.434
6.323
6.397
10 dB
2.12
1000
2.096
2.145
2.108
2.132
20 dB
0.636
1000
0.6287
0.6434
0.6323
0.6397
30 dB
0.212
1000
0.2096
0.2145
0.2108
0.2132
Table 8.
AI AC Coupled Gain Accuracy Limits for NI 4492/4497/4499
Device
Gain
Calibrator
Output
As Found
Test Limit
As left
Test Limit
Amplitude
(V
rms
)
Frequency
(Hz)
Min
(V
rms
)
Max
(V
rms
)
Min
(V
rms
)
Max
(V
rms
)
0 dB
6.36
1000
6.323
6.397
6.342
6.378
10 dB
2.12
1000
2.108
2.132
2.114
2.126
20 dB
0.636
1000
0.6323
0.6397
0.6342
0.6378
30 dB
0.212
1000
0.2108
0.2132
0.2114
0.2126
