indicators inside for loop does not display value in Main VI

[josephkirmani]

I have few indicators one is array and another one is displaying image inside FOR loop in the sub vi (see attached files). If I run sub vi individually it works fine but when I call those indicators in my main vi it does not show any thing and those indicators appear to be empty or blank, although at the same time the sub vi shows those indicator values perfectly. 

Can any body guide me why I cannot see those indicators properly in main vi although I can see them in the sub vi properly.

[Taki1999]

Take the tutorials on LabVIEW and think dataflow.

If you want information from inside your subVI for loop to be available to your main VI, you'll have to pass it in a manner where the main VI isn't waiting for the for loop to finish.

You can do this with control references. You could also pass the data out of the subVI using a notifier or a queue.

Depending on what you actually want to do, you may want to pick a different architecture for handling your image.

[josephkirmani]

Can you provide me any document or guide link which explains how to use Control Reference with For loop. I found Control Reference guide but it only explains with While loop. Also I did not find any document which explain how to use queue and notifier with for loop. 

[Taki1999]

The guide you link to will work the same in a for loop as it does in a while loop.

For an example of passing data from loops using queues, take a look at the Producer Consumer White Paper.

[RavensFan]

What do you expect to be different about a For Loop vs. a While Loop?

They are both loops with somewhat different methods for determining how many times to iterate.

[josephkirmani]

I tried both while and for loop but using control references technique does not work for any of them. Can you please exactly guide me what should I exactly do to make it work?

Many thanks for your support.

[RavensFan]

Post the VI's where you've tried this.

It is much easier to work with something you've already started and then figure out where things went wrong.

[josephkirmani]

Control reference files attached

[Taki1999 · Accepted solution]

The control references you want to pass to your VI are the Image and Output Array References if you want those to update.

Then, in your subVI, write to the property nodes of those references if you want to see the updates on your Main VI.

EDIT: While this method may get you around your immediate problem, I don't think this is something you really want to do often. There is probably a better way to architect this to achieve your real desired result.

[josephkirmani]

I did not get your point clearly. Can you explain in detail or if possible attach screen shot so that I can understand easily.

Many thanks.