single-step debug help

[cchipman]

Hi

I am new to LabVIEW and have read "LabVIEW for Everyone". I have inheirited a non-trivial LabVIEW app to which I had to add a feature and now it does not work. Basically, within an infinite while loop (the program runs continuously), there is a sequence structure.The program runs the sequence as expected the first time through but after that, the program runs away. By that, I mean that it goes off to do some next step but I cannot find it anywhere on the block diagram. I have single-stepped all the way up to "finish sequence structure" but the next step is just gone. The sequence structure frame remains on the final sequence, the loop counter on the infinite loop does not increment. The run arrow says it is running but nothing is happening and the stepping controls no longer work. It should not be in some lower level VI but it may be. Also, highlighting execution does not show anything either. Is there some way to find where the program is executing?

Thanks

Colin

[asbo]

Can you post the code? Either way, sounds like you could benefit from converting the code to a state machine.

[cchipman]

Thanks for the reply, but no, the code itself is pretty large and not revealing. My question is more along the lines of given this situation, what debugging techniques do you use? I have used the standard execution highlighting and single-stepping, but they don't seem to be working here. Is there any more sophisticated techniques?

[smenjoulet]

Thanks for the reply, but no, the code itself is pretty large and not revealing. My question is more along the lines of given this situation, what debugging techniques do you use? I have used the standard execution highlighting and single-stepping, but they don't seem to be working here. Is there any more sophisticated techniques?

You say you are single-stepping, but are you stepping into the various subVI's or just stepping over the subVIs. It sounds like it may be stuck in a dll call. Are you communicationg with any hardware? DAQ, GPIB, that sort of thing?

Normally, during execution highlighting, the currently executing subVI(s) should have a green arrow overlayed on top of the icon. Can you seen that anywhere when the execution appears stuck?

Can you post at least a screen capture of the top level diagram so we can see what is being used?

-Scott