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Figure 44. 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 cRIO 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.

Getting Started with DO Applications in Software

You can use the cRIO controller in the following digital output applications:

• Single-point (on-demand) generation

• Hardware-Timed Single Point generation

• Finite generation

• Continuous generation

For more information about programming digital output applications and triggers in software,

refer to the NI-DAQmx Help or to the LabVIEW Help.

Digital Input/Output Configuration for NI 9401

When you change the configuration of lines on a NI 9401 digital module between input and

output, NI-DAQmx temporarily reserves all of the lines on the module for communication to

send the module a line configuration command. For this reason, you must reserve the task in

advance through the DAQmx Control Task before any task has started. If another task or route

is actively using the module, to avoid interfering with the other task, NI-DAQmx generates an

error instead of sending the line configuration command. During the line configuration

command, the output lines are maintained without glitching.

PFI with NI-DAQmx

You can configure channels of a parallel digital module as Programmable Function Interface

(PFI) terminals. The cRIO controller also provides one terminal for PFI. Up to two digital

modules can be used to access PFI terminals in a single controller

You can configure each PFI individually as the following:

• Timing input signal for AI, AO, DI, DO, or counter/timer functions

• Timing output signal from AI, AO, DI, DO, or counter/timer functions

National Instruments cRIO-904 Series User Manual

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