Agilent Technologies 3458A User Manual page 163

control
The control parameter choices are:
Control
Parameter
OFF
ON
ONCE
Power-on control = ON
Default control = ON
•
Remarks
When autozero is ON, the multimeter makes a zero measurement (measurement
with the input disabled) following every reading and algebraically subtracts the
zero measurement from the reading. This approximately doubles the time
required per reading.
•
Notice that the control parameters OFF and ONCE have the same effect. When
autozero is OFF or ONCE, the multimeter makes one zero measurement and
algebraically subtracts this from subsequent readings. After you execute
AZERO OFF or AZERO ONCE, the multimeter takes the autozero
measurement when the first trigger arm event occurs for all events except
TARM EXT which causes an autozero measurement when the TARM EXT
command is executed. The autozero measurement will be updated whenever the
measurement function, range, or integration time is changed (this update will
be made when the trigger arm event occurs or TARM EXT is executed).
•
The display annunciator AZERO OFF illuminates when autozero is disabled.
•
Autozero cannot be disabled for DC current measurements.
•
For 2-wire ohms measurements with offset compensation enabled, the zero
measurement and offset measurement are done simultaneously.
•
Autozero should be on for 4-wire ohms measurements. If you must disable
autozero, be sure to make all measurement connections before disabling
autozero and ensure that the lead resistance will not change. If you disable
autozero before making the 4-wire connections, or if you have a varying lead
resistance with autozero disabled (such as when scanning), you will get
inaccurate 4-wire ohms measurements.
•
Query Command. The AZERO? query command returns the present autozero
mode. Refer to "Query Commands" near the front of this chapter for more
information.
•
Related Commands: DCI, DCV, FUNC, OHM, OHMF
Example
OUTPUT 722; "AZERO OFF" !DISABLES AUTOZERO
Numeric
Query
Equiv. Description
0 Zero measurement is updated once, then only after a
function, range, aperture, NPLC, or resolution change.
1 Zero measurement is updated after every measurement.
2 Zero measurement is updated once, then only after a
function, range, aperture, NPLC, or resolution change.
Chapter 6 Command Reference
AZERO
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