B+K precision 5490C Series, User Manual

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Step 3: Range selection.
Press Range and select the range. Auto range (Auto) can automatically select the appropriate range for
measurement based on the input signal. The auto range is adjusted upwards to 120% of the existing
range and down to 10% of the existing range.
Step 4: Set the integration time.
The setting of the integration time affects the measurement speed and measurement accuracy. The
longer the integration time, the higher the accuracy but the slower the measurement. 1PLC, 10PLC,
and 100PLC can inhibit noise. Selecting 100PLC can provide the best noise rejection, but at a slower
rate.
Step 5: Auto Zero.
Auto-zeroing results in more accurate measurements but requires more test time. With auto zero
enabled, the digital multimeter measures the offset once and subtracts the offset from all
subsequently measured parameters. This avoids the effect of the offset voltage on the input circuit of
the digital multimeter on the measurement accuracy. The DMM makes a new offset measurement
each time you change the function, range, or integration time. The default state is ON.
Step 6: Input Z internal resistance selection
Select the data input impedance. The input impedance can be automatic or 10MΩ. Automatic mode
selects high impedance (HighZ), which is appropriate for 100 mV, 1 V, 10 V ranges. The internal
resistance of the 100 V and 1000 V ranges is fixed at 10 MΩ.
Note: When attempting to measure a unipolar AC+DC signal in DCV mode, manual ranges should be
used for best accuracy.