Use the AO Pause Trigger signal (ao/PauseTrigger) to mask off samples in a DAQ sequence. When AO Pause Trigger is active, no samples occur, but AO 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 analog 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 33. AO 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 34. AO Pause Trigger with Other Signal Source

Using a Digital Source

To use AO 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 AO Pause Trigger is at a logic high or low level. Refer to the Device Routing in MAX topic 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.