I would like to use a queue to manage multiple tasks that must be executed at periodic intervals. The number of events and the time between them will not be defined until runtime. These are not "front panel" events or "user events" but background execution events like "read temperature" or "measure voltage" The most fundamental implementation might use a cluster with a long integer to store the execution time and a string to indicate the name of the event to be raised at that time. References to each event could be added to the queue in any number and in any order. Instead of handling the queue in the standard FIFO order, the queue will be sorted by execution time. The bottom loop with monitor the queue and raise the events as the test runs. The loop previews the front-most element in the queue until the current time is equal to or greater than the execution time of the event. Then the cluster would be dequeue and raise the event before being discarded. I'm confident I can assemble and sort the queue but I'm having trouble with the handling loop below. I can't seem to convert the cluster references back to cluster objects in order to access the numeric and string contents. I tried using the functions below but with no success. Also, I'm unclear exactly how each event gets raised or triggerd when its execution time has arrived. I realize the code I've attached is not functional but I wanted to keep it simple and I'm only asking questions about the bottom loop. The queue I'm describing should be distinct from the internal event queue LabVIEW uses to respond to Front Panel input and updating indicators. I've also added an image of my block diagram and the vi file. I'd appreciate ideas and suggestions to move this forward. Thanks. Here is my block diagram

@skinnedknuckles wrote: Hey Wiebe, Thanks for elaborating. This is very helpful. I hear you saying that queues and events are redundant and I should pick one or the other. Maybe I should back up and ask more fundamental questions. What if I have 4 different background data collection tasks or actions that I need to execute every 1, 5, 15 and 60 seconds repectively for 4 days. What data structure would you use to represent these tasks or actions and how would you organize them? What kind of container would you use to store them that would allow you to sort them and execute each one at it's designated time? I thought a queue of clusters would serve this purpose and that's why I picked it. Are there alternative data structures and containers you'd prefer to manage a large collection of tasks or actions? A cluster in an array does that. You don't really need a queue at all. If all actions are predefined, you can simply make a VI that returns an array of actions (class or cluster, enum, string, whatever). You can then loop through that array. If you have processes that create the actions "on the fly", then you could indeed use a queue of clusters. Or a user event with the same cluster. That is what the image I send earlier does. In your original post you did create a queue of clusters. That could work. You then tried to add a user event registration to that queue. That didn't work. You need a queue of user event registrations to be able to enqueue a user event registration. You can enqueue a cluster in a queue of clusters.

LabVIEW

Custom Event Queue - converting cluster references to objects

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Thanks, making an array of clusers turned out to be the solution I needed.

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Custom Event Queue - converting cluster references to objects

Re: Custom Event Queue - converting cluster references to objects