i want to run one vi in teststand sequence only one time just the first round,and the vi willnot run in the later, how to realize it ?

[walter.shao]

THANKS

[Dennis_Knutson]

You can add a SequenceFileLoad callback and put the VI in there. The VI would only execute when you first load the sequence but not during the sequence run.

[tbob]

You could also call the vi from the Setup tab. All steps in the Setup tab will run once before the Main. After that, the Main runs continuously until you press the stop button which appears after each run. After that, the steps in the Cleanup tab run once.

[Dennis_Knutson]

Actually, every time a test sequence is run, setup, main, and cleanup is run every time. Putting a VI in the setup of the sequence model will work though.

[tbob]

Sorry, I was thinking sequence model when I was writing and I forgot to mention it in my reply. The setup for the sequence model occurs once, then the main runs with all the callbacks and such until the user tells it to stop, then the sequence model cleanup runs. Thanx for pointing that out, Dennis. To me, using the setup tab is an easy and straightforward way of doing this. The steps are easy to find rather than having it buried in a callback step.

[Dennis_Knutson]

I don't disagree and have put some generic steps in the setup of my process model. It's when I need something unique for one UUT and it's sequence that the callback works.

[Eric M]

Walter,

You could also use a FileGlobal boolean that is initialized to false. Have a precondition for the step be a check on the value of the boolean. Then, have a Post Expression on the step set the boolean to True. Only this sequence file is affected this way.

Eric