National Instruments cRIO-904 Series User Manual

National Instruments cRIO-904 Series User Manual Manual pdf 71 page image

Figure 44. DO Pause Trigger with Other Signal SourcePause TriggerSample ClockUsing a Digital SourceTo use DO Pause Trigger, specify a source and a polarity. The source can be a PFI signal orone 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 highor low level. Refer to the "Device Routing in MAX" topic in the NI-DAQmx Help or theLabVIEW Help for more information.Getting Started with DO Applications in SoftwareYou can use the cRIO controller in the following digital output applications:• Single-point (on-demand) generation• Hardware-Timed Single Point generation• Finite generation• Continuous generationFor 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 9401When you change the configuration of lines on a NI 9401 digital module between input andoutput, NI-DAQmx temporarily reserves all of the lines on the module for communication tosend the module a line configuration command. For this reason, you must reserve the task inadvance through the DAQmx Control Task before any task has started. If another task or routeis actively using the module, to avoid interfering with the other task, NI-DAQmx generates anerror instead of sending the line configuration command. During the line configurationcommand, the output lines are maintained without glitching.PFI with NI-DAQmxYou 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 digitalmodules can be used to access PFI terminals in a single controllerYou 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 functionscRIO-904x User Manual | © National Instruments | 71