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Verification and Calibration - B
151
DVM Measurement Accuracy
This test verifies the DVM measurement accuracy. Connect all equipment as shown in figure B-1D.
Action Normal Result
1. Turn off the dc source and connect the external DMM and the
external power supply to the DVM inputs as shown in figure B-1D.
Connect only the negative output lead of output 1 to the DVM
inputs. Then turn on the dc source and select Output 1.
2. Set output 1 to zero volts and the external power supply to 25 volts.
Output voltage near 0 V
3. Record the external (3458) DMM reading (Dvpos) and the internal
DVM reading.
Internal DVM reading should be
within positive voltage limits.
(see Table B-3, B-4).
4. Set output 1 to 15 V and repeat step number 3. Internal DVM reading should still be
within positive voltage limits.
(see Table B-3, B-4).
5. Reverse the leads of the external power supply to the DVM inputs.
Keep all other connections the same.
Output voltage near 15 V
6.
With output 1 set to 15 V, lower the voltage on the external power
supply until the external (3458) DMM reads −4.5 V.
Output voltage near 15 V
7. Record the external (3458) DMM reading (Dvneg) and the internal
DVM reading.
Internal DVM reading should be
within negative voltage limits.
(see Table B-3, B-4).
8. Set output 1 to zero volts and repeat step number 7. Internal DVM reading should still be
within negative voltage limits.
(see Table B-3, B-4).