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Timer Process Library

This process implements timer tasks that other processes register by sending Qbus messages to those processes. When a process registers a timer task, the Timer process sends a particular type of Qbus message at a configurable time interval to cause the original process to execute the desired subdiagram. This works similarly to a callback in that this process can also return a value along with the name of the subdiagram to execute.


Actions Performed

  • Creates a new timer task a process registers it.
    • Ensures only instance of a task with a particular name exists by overwriting previous versions with the most recent one.
    • Starts counting time upon receipt of the RegisterTimerEvent message.
  • Evalutes whether any timers for registered timer events have expired.
    • Initiaties the callback action by sending a routed message to the originating process. Recall that you specify the return process, message name, and message value when you register an event, so this process uses that information to create the routed message.
    • If the event type was to be performed a single time, removes the task from the internal list of timer tasks.
  • Unregisters a task upon receipt of an Unregister message whose value is the name of that task.


The palette for the Timer Process Library can be found under Addons.


The process will run asynchronously next to the rest of the application.





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VersionDateDescription/Changes 2016Initial Release


Use VI Package Manager (VIPM) to install this library.

Timer Process Library on VIPM