Step 5: Press Aperture and choose the number of power-line cycles (PLCs) to use for the measurement. Only 1, 10,
and 100 PLC provide normal mode (line frequency noise) rejection. Selecting 100 PLC provides the best noise rejection
and resolution, but the slowest measurements.
Step 6: Specify whether you want to use Auto Zero. Autozero provides the most accurate measurements, but
requires additional time to perform the zero measurement.
With autozero enabled, the DMM internally measures the offset following each measurement. It then subtracts that
measurement from the preceding reading. This prevents offset voltages present on the DMM’s input circuitry from
affecting measurement accuracy. With autozero disabled, the DMM measures the offset once and subtracts the offset
from all subsequent measurements. The DMM takes a new offset measurement each time you change the function,
range, or integration time.
40 Agilent Truevolt Series DMM Operating and Service Guide