Keysight Technologies 3458A Guide D'utilisation page 77

Autocalibration
The multimeter has four autocalibration (autocal) routines: DCV, AC, OHMS, and
ALL. These routines improve short-term accuracy for many or all measurement
functions, but are not substitutes for periodic external calibration of the
multimeter. The measurement functions affected by each routine are:
– The DCV routine enhances all measurement functions. This routine takes about
– The AC routine performs specific enhancements for AC or AC+DC voltage (all
– The OHMS routine performs specific enhancements for 2 or 4-wire ohms. DC
– The ALL routine enhances all measurement functions by performing all of the
You should not cycle power or reset the multimeter while an autocal routine is
NOTE
being performed. If you do, the multimeter generates the ACAL REQUIRED error
(since many or all of its autocal constants have been erased). You must then
perform the ALL routine to eliminate the error.
Since the DCV routine applies to all measurement functions, you should perform
the DCV autocal before performing the AC or OHMS autocal, or perform ALL of
the routines (see second example below).
Running autocal
Suppose you intend to make 4-wire ohms measurements. The DCV autocal
routine increases the short term accuracy for all measurements and the OHMS
autocal enhances resistance measurements (and current measurements). The
following program performs the DCV autocal followed by the OHMS autocal.
10 OUTPUT 722; "ACAL DCV"
20 OUTPUT 722; "ACAL OHMS"
30 END
Keysight 3458A User's Guide
1 minute to perform.
measurement methods), AC or AC+DC current, direct- or sub-sampled
digitizing (AC- or DC-coupled), frequency, and period measurements. The AC
routine takes about 1 minute to perform.
current, and AC current measurements. The OHMS routine takes about
10 minutes to perform.
above routines. The ALL routine takes about 11 minutes to perform.
Configuring for Measurements 3
77