10.4-56
Section 10: Calibrating the Model 9100: Insulation Resistance Function
Final Width = 215mm
10.4.9.6
Verification of Output Voltage Display
It is not possible to adjust the factors which scale the display of output voltage in the 9100's
Insulation Resistance mode. However, a suitable method of verification is as follows:
1. Connect the insulation tester across the HI and LO terminals of the 9100 as shown in
Fig. 10.4.9.1.
2. Set the 9100 to MANUAL mode and select the insulation resistance function.
3. Connect a 1271 (or equivalent long scale DMM across the HI and LO terminals of the
9100, with the 1271 input switched to DCV on the 1000 volt range (i.e. the 1271 is
connected in parallel with the 9100 output terminals).
4. Set the 9100 output impedance to be 1.000M
Ω
.
5. Select the 500V test range on the insulation tester.
6. Turn the 9100 output ON.
7. Press the TEST button on the insulation tester.
8. Note the voltage displayed on the 9100 output screen versus the voltage displayed on
the 1271 and confirm that the 9100 displayed voltage is within its published
specification of
±
(0.6% + 1.5V).
9. You will note that the insulation tester will display an impedance of approximately
0.91M
Ω
- this is because of the 10M
Ω
input impedance of the 1271 seen in parallel
with the 1M
Ω
impedance being generated by the 9100.
10. Release the TEST button on the insulation tester.
11. Turn the 9100 output OFF.