How can I stop and restart a .vi with a single front panel button?

[Tomaz79]

Hey guys, a newbie here.

I have a .vi with a stacked sequence. The first few frames are hardware initialization and settings (LIN master node) and the data the hardware should transmit (frame response table). In the next frame there's a loop in which the hardware sends and recieves data (LIN monitor). If I want to change the initialization, settings or data values, I have to stop the .vi and restart it. I was wondering if there is a simple way of doing this with a single click (a button on the front panel).

An alternative would be to put another loop outiside the whole stacked sequence and then run it a single time with a push of a button (the inner loop should let the outer one restart), is that possible?

I hope I made any sense. Thanks for any suggestions.

Tomaz

[Gak]

Hi,

 Can you post your vi?

[Tomaz79]

It has about 100 custom subVIs, I don't think posting it would be of much use. Basically, the vi goes like this:

stacked sequence: do A -> do B -> do loop until "stop".

I'd like a way to start again from the beginning of the sequence ("do A") without stopping and restarting the VI (or doing this with a single button).

[jcarmody]

Sounds like you need a State Machine.  It's pretty easy to implement.

[AdnanZ]

Do what Jim suggested and try to work with a State Machine; you can find a template at File -> New.. and in Design Patterns, you should be able to find the Standard State Machine template. Try to work with it and post your test VI if you get stuck somewhere.

[Broken_Arrow]

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Tomaz79 wrote:

I'd like a way to start again from the beginning of the sequence ....

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Take the great advice given. Think of a State Machine as LabVIEW's only way to do a GoTo statement, or even a GoSub statement with a Return.

[LV_Pro · Accepted solution]

Ideally, redoing the code with a state machine would be the best way to go, if only so that you can add this powerful tool to your toolbox. That being said, wrapping your existing code in a while loop, with its own stop button to stop the program, will work if executing the entire sequence is ok. Where you might run into problems with this is if there is a step in the sequence that shouldn't be executed again, then it would require wrapping that sequence frame's code in a case statement that executes only the first time through. If you have the time, learning how to use a state machine would be a real benefit, really taking your LabVIEW knowledge to the next step, if you pardon the pun.

[Tomaz79]

Thanks for the suggestions, I'll try it and report back.

Tomaž

[Tomaz79]

It turned out that wrapping everything in a while loop was all I needed for this case. I also learned how to use a state machine so thanks to all of you guys for the help!

Tomaž

[jasper96]

hi guys this my vi file how should i stop and restart the program