National Instruments NI cDAQ-9139 User Manual page 72

Chapter 4 Digital Input/Output and PFI
Figure 4-5. DO Pause Trigger with the Onboard Clock Source
If you are using any signal other than the onboard clock as the source of the sample clock, the
generation resumes as soon as the pause trigger is deasserted and another edge of the sample
clock is received, as shown in Figure 4-6.
Figure 4-6. DO Pause Trigger with Other Signal Source
Pause Trigger
Sample Clock
Using a Digital Source
To use DO Pause Trigger, specify a source and a polarity. The source can be a PFI signal or one
of several other internal signals on the cDAQ controller.
You also can specify whether the samples are paused when DO Pause Trigger is at a logic high
or low level. Refer to the Device Routing in MAX topic in the NI-DAQmx Help or the
LabVIEW Help for more information.
Using an Analog Source
Some C Series modules can generate a trigger based on an analog signal. In NI-DAQmx, this is
called the Analog Comparison Event, depending on the trigger properties.
When you use an analog trigger source, the samples are paused when the Analog Comparison
Event signal is at a high or low level, depending on the trigger properties. The analog trigger
circuit must be configured by a simultaneously running analog input task.
Depending on the C Series module capabilities, you may need two modules
Note
to utilize analog triggering.
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Pause Trigger
Sample Clock