Serial DIO versus Parallel DIO Modules

Serial digital modules have more than eight lines of digital input/output. They can be used in any controller slot and can perform the following tasks:
  • Software-timed and hardware-timed digital input/output tasks
Parallel digital modules can be used in any controller slot and can perform the following tasks:

  • Software-timed and hardware-timed digital input/output tasks

  • Counter/timer tasks (can be used in up to two slots)

  • Accessing PFI signal tasks (can be used in up to two slots)

  • Filter digital input signals

Software-timed and hardware-timed digital input/output tasks have the following restrictions:

  • You cannot use parallel and serial modules together on the same hardware-timed task.

  • You cannot use serial modules for triggering.

  • You cannot do both static and timed tasks at the same time on a single serial module.

  • You can only do hardware timing in one direction at a time on a serial bidirectional module.

To determine the capability of digital modules supported by the controller, refer to the Software Support for CompactRIO, CompactDAQ, Single-Board RIO, R Series, and EtherCAT document.