National Instruments Eight-slot USB Chassis NI cDAQ-9172 - Manual (Page 24)

NI cDAQ-9172 User Guide and Specifications 24 ni.com
AI Pause Trigger Signal
You can use the AI Pause Trigger (ai/PauseTrigger) signal to pause and
resume a measurement acquisition. The internal sample clock pauses while
the external trigger signal is active and resumes when the signal is inactive.
You can program the active level of the pause trigger to be high or low.
Using a Digital Source
To use ai/PauseTrigger, specify a source and a polarity. The source
can be either from PFI or one of several other internal signals on
your NI cDAQ-9172 chassis. Refer to the Device Routing in MAX topic in
the NI-DAQmx Help or the LabVIEW Help in version 8.0 or later for more
information.
The NI-DAQmx Help is available after installation from Start»
All Programs»National Instruments»NI-DAQ»NI-DAQmx Help.
To view the LabVIEW Help, in version 8.0 or later, select Help»
Search the LabVIEW Help in LabVIEW. Alternately, to download
the LabVIEW Help, go to
ni.com/manuals .
Using an Analog Source
Some C Series I/O modules can generate a trigger based on an analog
signal. In NI-DAQmx, this is called the Analog Comparison Event.
When you use an analog trigger source, the internal sample clock pauses
when the Analog Comparison Event signal is low and resumes when the
signal goes high (or vice versa).
Note Pause triggers are only sensitive to the level of the source, not the edge.
Analog Input Timing Signals
AI Sample Clock
A sample consists of one reading from each channel in the AI task.
ai/SampleClock signals the start of a sample of all analog input channels
in the task. ai/SampleClock can be generated from external or internal
sources.