How to stop instances of a subvi from sharing data?

[km4hr]

Thanks for your help johnsold.

How much you want for your converted program that uses shift registers instead of the feedback loop?

regards

[Ben]

See here for my Nugget on Action Engines which makes use of Un-initialized Shift Registers (USR).

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km4hr wrote:

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I'll have to do some more studying about un-initialized data (?).

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Regarding payment...

Everyone who has gold/yellow bars under their icon OR are a Knight of NI are all volunteers. We all work for Kudues (Copyright C Altenbach 2008).

Ben

[johnsold]

Just context-click on the feedback node and choose "Replace with Shift Register" from the pop-up menu.

The issue is not that a feedback node is prohibited in a subVI.  Your subVI is called more than once in the loop.  The feedback node inside the subVI retains data from the previous call, so the data gets mixed between the two channels.  Here is where a re-entrant VI may be of value.

You may find the tutorials and the LabVIEW Help useful in learning more about these issues.  Search the help for terms like "dataflow," feedback node," and "reentrant."   You will get more hits than will be initially useful, but pick out some of the more general topics first.

Lynn 

[km4hr]

Ravens,

Bingo! Setting the subVI for reentrant execution instead of the setting it in the main VI did the trick. I like this solution because it allows the subVI to "make sense" (at least to my current limited understanding anyway). It may not make optimal use of memory but that's ok. Memory is cheap. I'm an engineer, not a scientist. My first priority is to make it work so I can put it to use. 

I'll keep the things in mind that have come up in this discussion. I'm sure they'll have more meaning as I continue to study/use LV. I'll even consider Ben's "nugget", even though it looks more like a boulder to me.

 regards