Use the DO Pause Trigger signal (do/PauseTrigger) to mask off samples in a DAQ sequence. When DO Pause Trigger is active, no samples occur, but DO Pause Trigger does not stop a sample that is in progress. The pause does not take effect until the beginning of the next sample.

When you generate digital output signals, the generation pauses as soon as the pause trigger is asserted. If the source of the sample clock is the onboard clock, the generation resumes as soon as the pause trigger is deasserted, as shown in the following figure.

Figure 39. 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 the following figure.

Figure 40. DO Pause Trigger with Other Signal Source

Using a Digital Source

To use DO Pause Trigger, specify a source and a polarity. The source can be a PFI signal on an installed C Series module or one of several other internal signals on the cDAQ chassis.

You also can specify whether the samples are paused when DO Pause Trigger is at a logic 
high or low level. Refer to Device Routing in MAX in the NI-DAQmx User Manual 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.

Note Depending on the C Series module capabilities, you may need two modules to utilize analog triggering.