How to probe wires in a subIV

[niel_malan]

Hi

I'm a bit new to LabVIEW, so I'm allowed to ask stupid questions.

I'm running a biggish application in LabVIEW, and of course some of the bits run in subVIs. I find that I can't probe the wires of some of the subVIs, or set breakpoints. For I while I thought that was just the way things were, but in some of the subVIs, it does work.

What am I missing?

I'm running LabVIEW 7.1

[Graziano]

Exactly, what kind of subVI can't you probe?

You can set, in VI properties, Allow debug, and also if a VI is reentrant you can't debug it!

Hope it can help...

graziano

[altenbach]

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@Graziano wrote:
You can set, in VI properties, Allow debug, and also if a VI is reentrant you can't debug it!

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Actually, newer versions of LabVIEW allow debugging of reentrant VIs. See:

https://www.ni.com/docs/en-US/bundle/labview/page/suggestions-for-using-execution-systems-and-priori...

[niel_malan]

Hi Graziano

Thank you very much for you help. I found that my subVI was re-entrant.

You ask "Exactly, what kind of subVI can't you probe?" What kinds of subVI's are there.

Regards

Niel

[tbd]

Hi niel_malan,

      Re: no probing reentrant VIs under LV 7.1 - I feel your pain!  When especially desperate, I pump the value-of-interest into an OK Dialog.  Of course it's easier to debug with only 1 instance running, but if multiple instances are necessary it may be possible to put a case around the dialog so only a specific instance will write to the dialog - or have the dialog include some instance-specific identifier.  If you use this Dialog method much, it's also helpful to include some info to identify what VI the Dialog is located in (to help remove it later -.)

First, though, look around the diagram for some non-rentrant SubVI that the value is wired-to.  It may be possible to see the value-of-interest by simply examining the controls of a Sub-VI.  You can even build a special-purpose sub-VI just for this.  Don't forget about breakpoints as a tool for trapping values.

Cheers!

[parthabe]

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@altenbach wrote:

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@Graziano wrote:
You can set, in VI properties, Allow debug, and also if a VI is reentrant you can't debug it!

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Actually, newer versions of LabVIEW allow debugging of reentrant VIs. See:

https://www.ni.com/docs/en-US/bundle/labview/page/suggestions-for-using-execution-systems-and-priori...

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But still a Reentrant SubVI of Subroutine priority cant be debugged.

[altenbach]

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@parthabe wrote:
But still a Reentrant SubVI of Subroutine priority cant be debugged.

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A subVI with subroutine priority cannot be debugged, period. Reentrant or not reentrant. 🙂

[parthabe]

Thats what I implied, Altenbach.

What I meant to say was, even if it is Reentrant VI of version 8.5, it still cant be debugged if its Priority was set to Subroutine.

[Graziano]

Hi Altenbach and parthabe,
   Thanks for your replies, maybe I've found new reasons to switch to newer labView... even if I'm skeptical about this feature'I mean, when you probe a Reentrant subVI, you are probing one instance of it... or you can open all instances called in different windows?

   Have a nice day!

graziano

[altenbach]

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@Graziano wrote:
I mean, when you probe a Reentrant subVI, you are probing one instance of it... or you can open all instances called in different windows?

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Yes, you can open and probe every instance seperately. They will be indicated as "clones" in the title bar of the window.