Integration Time And Resolution - Agilent Technologies 3458A User Manual

Integration Time and
Resolution
104 Chapter 4 Making Measurements
Table 22: Commands Executed by PRESET FAST
Command
DCV 10 Selects DC voltage measurements on the 10V range, which disables
autorange. The autorange function samples the input before each
reading, taking more time per reading than readings made on a fixed
range. The disadvantage of a fixed range is lower resolution for signals
that are less than 10% of full scale and the possibility of an overload
condition for readings greater than full scale.
AZERO OFF With autozero enabled, a zero measurement is made following each
reading (for DC measurements only), which increases the time per
reading.
DISP OFF The time required for the multimeter to update its display slows the
reading rate.
MATH OFF Any enabled real-time math operation(s) slow the reading rate. If you
must perform math operations on readings, use the post-process math
(MMATH command). Refer to "Math Operations" later in this chapter for
more information.
MFORMAT DINT Readings come from the A/D converter in either SINT or DINT format
(the format used depends on the specified measurement resolution; * in
the configuration selected by PRESET FAST, the A/D converter uses
DINT). The fastest way to transfer readings to reading memory is to
have the memory format (MFORMAT) match the A/D converter's format
so that no conversion is necessary. (Refer to "Reading Formats" earlier
in this chapter for information on when to use SINT or DINT).
OFORMAT DINT Readings come from the A/D converter in either SINT or DINT format
(the format used depends on the specified measurement resolution; * in
the configuration selected by PRESET FAST, the A/D converter uses
DINT). The fastest way to transfer readings to the output buffer is to
have the output format (OFORMAT) match the A/D converter's format
so that no conversion is necessary. In addition, when the output format
matches the reading memory format, no conversion is required to recall
readings from memory. Remember to use the ISCALE? command to
retrieve the scale factor when using the SINT or DINT output format.
(Refer to "Reading Formats" earlier in the chapter for information on
when to use SINT or DINT.)
* For direct-sampled digitizing, the format used depends on the amplitude of the
input signal. Refer to Chapter 5 for details.
DC, ohms, and analog AC measurements: The specified integration time
and/or resolution have a major effect on the reading rate for DC voltage; DC
current: 2-wire or 4-wire ohms; AC or AC+DC current: and AC or AC+DC
voltage (using the SETACV ANA method only). The longer the integration
time (or the greater the resolution), the slower the reading rate. The
specifications in Appendix A show selected reading rates for each of these
measurements based on integration time.
Sampled AC voltage measurements: For AC or AC+DC voltage
measurements using SETACV SYNC or SETACV RNDM, the integration
time is fixed and cannot be changed. For these measurements, the specified
resolution has a major effect on the reading rate. The specifications in
Appendix A show selected reading rates for sampled AC measurements
based on the specified resolution.
Reason