To generate digital output, install a digital output C Series module in any slot on the CompactRIO controller.

The generation specifications, such as the number of channels, channel configuration, update rate, and output range, are determined by the type of C Series module used. For more information, refer to the documentation included with your C Series module.

With parallel digital output modules (formerly known as hardware-timed modules), you can do multiple software-timed tasks on a single module, as well as mix hardware-timed and software-timed digital output tasks on a single module. On serial digital output modules (formerly known as static digital output modules), you cannot mix hardware-timed and software-timed tasks, but you can run multiple software-timed tasks.

You may have a hardware-timed task or a software-timed task include channels from multiple modules, but a hardware-timed task may not include a mix of channels from both parallel and serial modules. Multiple timing engines allow the CompactRIO controller to run up to eight hardware-timed digital output tasks simultaneously, each using independent timing and triggering configurations. The eight output timing engines are ot0, ot1,…ot7. All eight of the output timing engines are shared between analog output and digital output tasks, allowing up to eight hardware-timed output tasks.

Note (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.

Getting Started with DO Applications in Software

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

  • Single-point (on-demand) generation
  • Hardware-timed single-point (HWTSP) generation
  • Finite generation
  • Continuous generation

For more information about programming digital output applications and triggers in software, refer to Common Applications in the NI-DAQmx User Manual for more information.