Hello everyone. I'm looking for some help with a timing issue I am running in to in one of my larger VIs. The situation is essentially this: the VI has 3 simultaneously excecuting loops at any one time. One of these loops handles the user interface, updating things like the text in a text box, the fill level of a fill bar etc based on things the user is doing. It also controls the display for a countdown clock I've built into my program (it turns a text box green and displays a numeric variable controlled by my third loop as its text value). There is a wait function in this loop that ensures it excecutes no more than once every 20 milliseconds. The second loop maintains some properties of the front panel and changes them as needed. This has lower priority and has a wait function for 750 milliseconds to prevent it from running too frequently and slowing excecution. The third is by far the most important. It is the main piece of the program and the problem occurs in this third loop. It goes through its excecution well for its first trial (a 50 second run collecting mouse location and a few other variables) it then enters what is supposed to be a 10 second break. The break is divided into 2 sections, one lasting 5 seconds in which most of the values on the screen are locked into place and not much can change, and another, also 5 seconds, that writes a value to another computer through a LAN i have set up and then starts the countdown clock in the first loop to countdown from 5. The problem occurs in the interim between saving on the LAN and starting the countdown. For some reason rather than simultaneously excecuting as they do at all other points the program seems to focus on the first two loops and waits 6 to seven seconds before starting the countdown. I know its not the LAN connection as its only saving a 8 character text file and several other times in the program it saves these files within 1/10th of a second, and I've set probes and seen that the other two loops continue to excecute continuously the entire time the program is breaking. Does anyone have any idea why this might occur? If needed I can post pictures or a sample of the program but id prefer not to as i dont believe my lab wants many people knowing what we're studying until we publish. Any help would be appreciated! Thank you!

One of the characteristics of the sequence structure is that everything inside one frame must complete execution before the next frame can start. So if your write to file hangs up due to OS or communications issues, your program will be stuck there until the file write is complete. Parallel loops can minimize this type of problem by allowing the file operations to take as much time as they need without limiting the timing of the other loop (within limits of how much data you can buffer in one or both loops). Sequence structures severely constrain your flexibility. Best practices in LV generally avoid their use. A state machine is often a better choice. Lynn

LabVIEW

Problem with Timing

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Thank you so much. I'll look into that. Really all I needed was a push in the right direction thank you for helping with that.

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Problem with Timing

Re: Problem with Timing