Keithley 2461, Reference Manual, Page: 435 / 1109

Section 6: SCPI command reference Model 2461 Interactive SourceMeter® Instrument Reference Manual
6-58 2461-901-01 A/November 2015
Details
To ensure the accuracy of readings, the instrument must periodically get new measurements of its
internal ground and voltage reference. The time interval between updates to these reference
measurements is determined by the integration aperture that is being used for measurements. The
Model 2461 uses separate reference and zero measurements for each aperture.
By default, the instrument automatically checks these reference measurements whenever a signal
measurement is made.
The time to make the reference measurements is in addition to the normal measurement time. If
timing is critical, such as in sweeps, you can disable autozero to avoid this time penalty.
When autozero is set to off, the instrument may gradually drift out of specification. To minimize the
drift, you can send the once command to make a reference and zero measurement immediately
before a test sequence.
If you send this command without the
<function>
parameter, it sets autozero for all functions.
Example
VOLT:AZER OFF
Sets autozero off for voltage measurements.
Also see
Automatic reference measurements (on page 2-129)
[:SENSe[1]]:AZERo:ONCE (on page 6-72)