Fluke 35040 Operator's Manual page 63

Example: 299.9 to 300.0
Cause: Rounding error in measurement.
Action: None.
Explanation: The bias voltage is not actually changing. The control for the bias is in discrete steps.
The measurement is also in discrete steps. The control program may select a setting
that causes the measurement to be very near the transition between one measurement
step and the next.
Troubleshooting and Service
Troubleshooting
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