How to build reference from subvi to vi?

I have both vi and Subvi vi program, i try to link up the data "send data", "received data", "Listen to" boolean , how can i build references and use vi to control subvi
Attachments:
Machine_connection.vi ‏20 KB
Semester2.vi ‏34 KB

The code does not fit the way execution is controlled in LabVIEW, namely through data flow...Other key consepts to check out is locals, globals/functional globals...
I would also recommend you to use a left to right design on all code; inputs to the sub-vi should be on the left side of the VI, outputs on the right side...but back to the problem at hand:
There are a number of ways to solve this...the easiest is to simply not use a sub-vi, move the sub-vi code to the vi..that way the button will be read on each iteration and you can stop it...if the loop is in a sub-vi it will not read any new inputs nor output anything until it has finished (data flow).
If you still want the listener in a sub-vi and control it from the main vi put the button in a loop and u
se VI globals to share data (attached is an example for the button control; initialize it prior to doing anything else, then put the button in a while loop and wire it to the input of the global, with the function set to write...then replace the button in the listening VI with the global and set the funtion to read..wire the output the same way as the button used to be...You need to make similar globals for the send and receive data...a better option there htough would be to use ques, that way you will not loose any data.)
Other options include making the listening sub-vi load dynamically so that the calling vi does not wait for it to finish..and then share data between the two using a send and a receive que...
Search this site for functional globals to read more about the idea behind the VI global example...Also check out texts and examples on ques and client-server solutions...
MTO
Attachments:
Listen.vi ‏17 KB

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galXE1,
From my example you can use the invoke node method of "get all" and it will retrieve all the indicator names and values and then you can get the values you want.
Sorry for not posting this originally but without modifying your code a bunch your quickest option is to use shared variables. If you have important vital tasks they aren't the best but if you're just looking to pass data between vi's then they are you're easiest option.
Creating a Shared Variable - look at single process shared variable section.
http://zone.ni.com/devzone/cda/tut/p/id/4679
So you basically call your subvi every time the loop iterates to perform some execution and then you can update your main front panel with the newest values. Calling the subvi with a loop in it. Nothing special but it gets the job done. Its not very good practice if you have a bunch of values you want to pass.
See subvi calculations.jpg
A better approach to passing data between vi's is detailed in the document. Its called a Functional Global Variable.
https://decibel.ni.com/content/docs/DOC-12876
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Attachments:
Subvi calculations.JPG ‏42 KB

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For more info on User Events, refer to the LabVIEW help. You can learn more by clicking any of the User Event VIs and selecting Help from the shortcut menu.
(I didn't set the subVIs front panel to open automatically, so you'll have to do that yourself to see anything from this demo...)
Message Edited by Jarrod S. on 11-26-2007 02:51 PM
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