Autozero

When autozero is enabled (default), the instrument internally disconnects the input signal following each measurement, and takes a zero reading. It then subtracts the zero reading from the preceding reading. This prevents offset voltages present on the instrument’s input circuitry from affecting measurement accuracy.
When autozero is disabled, the instrument takes one zero reading and subtracts it from all subsequent measurements. It takes a new zero reading each time you change the function, range, or integration time.
Autozero applies to temperature, dc voltage, two-wire ohms, and dc current measurements only. Autozero is always enabled when you select four-wire ohms measurements.
The autozero mode is set indirectly when you set the resolution and integration time. Autozero is automatically turned off when you select an integration time less than 1 PLC.
The autozero setting is stored in non-volatile memory, and does not change when power has been off, after a Factory Reset, or after an Instrument Preset.