Calibration; Calibrating The Model 85 And 87 Iii - Fluke 87 III Series Service Information

Calibration

Calibrate the Meter once a year to ensure that it performs according to specifications.
Calibration adjustment points are identified in Figure 5.
There is a slightly different calibration procedure for each model of the 80 Series III. Be
sure to follow the correct procedure for your unit.

Calibrating the Model 85 and 87 III

To calibrate the Meter, perform the following procedure:
1. Set the Calibrator for 0 V dc.
2. Put the Model 85 III or 87 III in the L function.
3. Connect the Calibrator to the Vand COM inputs on the Meter.
4. Output 3.500 V dc from the Calibrator.
Adjust R21 to obtain a Meter display reading of 3.500 ±0.001.
5. Put the Model 85 III or 87 III in the K function.
6. Output 3.513 V at 50 Hz from the Calibrator.
Adjust R34 to obtain a Meter display reading 3.500 ±0.002.
The disparity between an input 3.513 and a display reading of 3.500 is
due to compensation for the RMS converter linearity.
7. Output 100 V at 20 kHz from the Calibrator.
Adjust C37 to obtain a Meter display reading of 100.0 ±0.2.
8. Output 3.500 V at 10 kHz from the Calibrator.
Adjust C2 to obtain a Meter display reading of 3.500 ±0.004.
9. Output 35.00 V at 10 kHz from the Calibrator.
Adjust C3 to obtain a Meter display reading of 35.00 ±0.04.
Note
Multimeters
Calibration
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