Dcv Remarks - Agilent Technologies 3458A User Manual

DCV Remarks

Note
The PRESET DIG command configures the multimeter for DC voltage
measurements with a sampling rate of 50,000 samples per second. PRESET
DIG selects a 3µs integration time and level triggering when the input signal
crosses zero volts on its positive slope. The primary commands executed by
PRESET DIG are:
TARM HOLD --
TRIG LEVEL --
LEVEL 0,AC --
TIMER 20E-6 --
NRDGS 256,TIMER --
DCV 10 --
DELAY 0 --
APER 3E-6 --
MFORMAT SINT --
OFORMAT SINT --
AZERO OFF --
DISP OFF --
After executing PRESET DIG, you can increase the sampling rate by
decreasing the TIMER interval and by reducing the integration time using
the APER command. The minimum integration time for DCV is 500
nanoseconds.
•
For DCV digitizing, you should use the SINT memory/output format when
the integration time is £ 1.4µs. Use the DINT memory/output format when
the integration time is >1.4µs. (These formats are discussed in detail in
Chapter 4.)
To achieve the fastest possible transfer of samples to reading memory and/or the
controller, you can use the SINT output/memory format for integration times up to
10.8ms. However when the integration time is >1.4ms, the A/D converter is
producing more bits of resolution than can be accommodated by the SINT format
(the least significant bit(s) are discarded). Whenever using the SINT
output/memory format with integration times >10.8ms, the multimeter must
convert the data coming from the A/D converter and cannot maintain the
high-speed mode. You should use the DINT memory/output format (which is
compatible with the high-speed mode) when the integration time is >10.8ms.
•
Whenever making measurements using the TIMER sample event or the
SWEEP command, autorange is disabled. You can use the range selected
by PRESET DIG (10V range) or specify the range as the first parameter
of the DCV or RANGE command (max_input parameter). The max_input
parameters and the ranges they select are:
Suspends triggering
LEVEL trigger event
Level trigger at 0% of range (0V), AC-coupled
20µs interval between samples
256 samples per trigger, TIMER sample event
DC voltage measurements, 10V range
No delay
3µs integration time
Single integer memory format
Single integer output format
Disables the autozero function
Disables the display
Chapter 5 Digitizing 135