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4
Making Measurements
85!AND ADVANCE TO CHANNEL 01, STARTING THE SCAN
90 END
Input complete
The input complete event (ICOMP event) is similar to the RCOMP event in that it
produces a 1 µs pulse for each reading. However, when the ICOMP event is
specified, the pulse occurs when the A/D converter has finished integrating the
input signal but before the reading is complete (see
can be used with an external scanner when making a single reading per scanner
channel. This event is especially important when using a slower (relay type)
scanner. Since the ICOMP event occurs before the reading is complete, it
advances the scanner sooner than would the RCOMP event. The following
program uses the ICOMP event to make one reading on each of 6 scanner
channels. Notice that line 40 enables trigger buffering. This prevents the
multimeter from generating the TRIGGER TOO FAST error should the scanner
output a channel closed pulse before the present reading is complete.
Connections for this example are shown in
10 OUTPUT 722;"PRESET NORM"!DCV, NRDGS,1,AUTO, TARM AUTO, TRIG SYN
20 OUTPUT 722;"MEM FIFO"!ENABLE READING MEMORY, FIFO MODE
30 OUTPUT 722;"TRIG EXT"!TRIGGER EVENT = EXTERNAL
40 OUTPUT 722;"TBUFF ON"!ENABLE TRIGGER BUFFERING
50 OUTPUT 722 "EXTOUT ICOMP,NEG"!INPUT COMPLETE EXTOUT, LOW-GOING TTL
55!CONFIGURE EXTERNAL SCANNER
60 OUTPUT 709;"SADV EXTIN"!ADVANCE SCANNER ON MULTIMETER'S EXTOUT
SIGNAL
70 OUTPUT 709;"CHCLOSED EXT"!OUTPUT LOW-GOING PULSE AFTER EACH CLOSURE
80 OUTPUT 709;"SCAN 201- 206"!SCAN CHANNELS 01 - 06 ON SCANNER IN SLOT
200
85!AND ADVANCE TO CHANNEL 01 STARTING THE SCAN
90 END
Aperture waveform
When specified, the aperture waveform event (APER event) outputs a waveform
indicating when the A/D converter is measuring the input signal. In addition to
showing when a reading is being measured, the aperture waveform also shows
any autozero and autorange measurements being made. This waveform can be
used to synchronize external switching equipment to the multimeter. For example,
to ensure an electrically quiet environment for high-accuracy measurements, it
172
Figure
4-5). The ICOMP event
Figure
4-6.
Keysight 3458A User's Guide
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