LabVIEW Timed Callback Handler
I have recently heard the same request repeatedly: "How do invoke an action in LabVIEW at regular intervals?" (The simple answer by the way: Timeout case of the Event Structure). But this quickly becomes a little more complicated when you want to perform potentially different actions at different intervals from many places, without having to copy/paste similar code over and over.
So here is a very lightweight class to do exactly that. This "TimerNotification" class allows for an unlimited number of these timers, to run independently and concurrently. The object takes a VI Path for the Callback VI to execute when the timer trigger hits.
Includes
- Timer Notification.lvclass
- Initialize.vi: Configure the object with a Callback VI Path, the Frequency of the timer, as well as optional data to pass to the Callback VI.
- Start.vi: Starts the timer and waits for the timer trigger.
- Stop.vi: Stops the timer from waiting.
- Uninitialize.vi: Cleans up the object and releases the Callback VI.
- Get Current State.vi: Gets the current state of the object.
- Two documented examples
- Example which demonstrates using multiple timers objects.
- Example which demonstrates passing complex data to the Callback VI, as well as sharing state information between runs.
- All public API VIs have context help and icons.
Software Required
Installation Instructions
- Download the attached .vip file.
- Double-click the .vip file.
- If VI Package Manager is not already installed, you should be prompted to download and install it.
- From with the VI Package Manager application, select the "Install " button.
Notes
- The Function Palette should get added to LabVIEW's default palette and titled "Timer Notification".
- I would be happy to hear comments or feedback if you have any! Add your comments below or send me a private message.
Known Issues
- The VIs do not have right-click shortcut palette entries.
- Selecting "Show Palette" from VI Package Manager brings up another palette. I assume this is because VI Package Manager searches for the first VI on the palette (which is Initialize.vi) and finds another on disk.
