Keysight Technologies 3458A Guide D'utilisation page 107

For analog AC measurements, if you default, the %_ resolution parameter, the
integration time will be that specified by the last NPLC command executed.
For sampled ACV or ACDCV, random sampling (SETACV RNDM) has a fixed
resolution of 4.5 digits that cannot be changed. For synchronous sampling
(SETACV SYNC) a %_resolution parameter of 0.001 = 7.5 digits; 0.01 = 6.5 digits:
0. 1= 5.5 digits: and 1 = 4.5 digits.
For frequency and period measurements, %_ resolution specifies the gate time
and the digits of resolution as shown in
program specifies frequency measurements from a voltage input using the 10 V
range. The %_resolution parameter in line 20 (.00001) specifies a gate time of 1
second and 7 digits of resolution.
10 OUTPUT 722; "FSOURCE ACV"
20 OUTPUT 722;"FREQ 10,.00001"
30 END
If you default the %_resolution parameter for FREQ or PER measurements, the
multimeter sets %_resolution to .00001 which selects a gate time of 1 second and
7 digits of resolution.
Table 3-11
When to specify resolution
For analog ACV or ACDCV (SETACV ANA), ACI, and ACDCI measurements, you
should specify resolution when you need more resolution than that provided by
the NPLC command. For example, in the following program, line 10 specifies
0.0001 PLC of integration time, which selects 5½, digits of resolution resulting in
an actual resolution of 100 µV on the 10 V range. However, for this application,
10 µV of resolution is required with a max._input of 10 V. The preceding equation
Keysight 3458A User's Guide
Frequency/Period gate time and resolution
%_resolution parameter
.00001
.0001
.001
.01
.1
Configuring for Measurements
Table 3-11. For example, the following
Selects gate time
1 s
100 ms
10 ms
1 ms
100 µs
Digits of resolution
7
7
6
5
4
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