National Instruments VirtualBench - DMM Adjustment

20 | ni.com | NI VirtualBench Calibration Procedure
14. Call DMM Read. Compare to the limits listed in Table 11.
Note Use the values in the 24 Hour Limits column for a post-adjustment
verification only. Otherwise, use the values in the 1 Year Limits column.
15. Repeat steps 12 through 14 for each verification point listed in Table 11.
16. Reset the calibrator for safety reasons.
17. Disconnect all cables from the calibrator and VirtualBench.
You have completed verifying the AC current function of the VirtualBench.
DMM Adjustment
This section explains how to adjust the VirtualBench DMM. You can choose to perform these
adjustment procedures with or without performing the verification procedures first.
Caution If you skip any of the steps within a section of the adjustment procedures,
NI VirtualBench does not allow you to store your new calibration coefficients.
Instead, NI VirtualBench restores the original coefficients to the EEPROM.
Note If verification was successful and you do not want to go through the
adjustment procedure, you can update the calibration date by calling Cal Set
Calibration Information
.
Note NI recommends repeating the verification procedures after you perform these
adjustment procedures. Re-verification ensures that the instrument you have
calibrated is operating within specifications after adjustments.
Table 11. VirtualBench AC Current Verification Limits ≥500 mA
Range
(A
rms
)
Verification
Point (A
rms
)
Frequency
(Hz)
1 Year Limits (A
rms
) 24 Hour Limits (A
rms
)
Lower Upper Lower Upper
0.5 0.03 40 0.02971 0.03030 0.02992 0.03008
0.25 40 0.24938 0.25063 0.24982 0.25018
0.505 40 0.50399 0.50601 0.50471 0.50529
5 0.3 40 0.2968 0.3033 0.2969 0.3031
2.5 40 2.4913 2.5088 2.4928 2.5072
5.05 40 5.0349 5.0651 5.0380 5.0620