Chapter 2
Analog Input
2-36
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Using an Analog Source
When you use an analog trigger source, the acquisition stops on the first
rising edge of the Analog Comparison Event signal. Refer to Chapter 10,
, for more information on analog triggering.
Outputting the AI Reference Trigger Signal
You can configure the PFI 1/AI REF TRIG pin to output the
ai/ReferenceTrigger signal. The output pin reflects the ai/ReferenceTrigger
signal regardless of what signal you specify as its source.
The output is an active high pulse. Figure 2-23 shows the timing behavior
of the PFI 1/AI REF TRIG pin configured as an output.
Figure 2-23.
PFI 1/AI REF TRIG Timing Behavior
The PFI 1/AI REF TRIG pin is configured as an input by default.
AI Pause Trigger Signal
You can use the AI Pause Trigger (ai/PauseTrigger) signal to pause and
resume a measurement acquisition. This signal is not available as an output.
Using a Digital Source
To use ai/PauseTrigger, specify a source and a polarity. The source can be
an external signal connected to any PFI or RTSI <0..6> pin. The source can
also be one of several other internal signals on your DAQ device. Refer to
Device Routing in MAX
in the
NI-DAQmx Help
or the
LabVIEW 8.x Help
for more information.
Also, specify whether the measurement sample is paused when
ai/PauseTrigger is at a logic high or low level.
t
w
t
w
= 50 to 100 ns