Using a Functional Global Variable to Communicate with a SubVI

[Hesloppy]

Overview:
This demo uses a Functional Global Variable (FGV) to communicate with a subVI.
Description:

The main VI launches the subVI using VI Server.  It then writes a value to a FGV.

Requirements:

• LabVIEW 2012 (or compatible)

Steps to Implement or Execute Code:

1. Run the Main VI.
2. Change the Numeric control.
3. Observe the changes in subVI.

 Additional Information or References

 "**This document has been updated to meet the current required format for the NI Code Exchange.**" 

[EWiebe]

Is this also possible if I start the subVI from an external packed library? It tried and it started, but tranferring data from MAIN to SUB (which comes from packed lib) did not work.

[crossrulz]

The problem you will run into with the PPL is that the PPL has its own copy of the FGV.  Therefore, you will not be communicating between a VI outside of the PPL and one inside of the PPL.

There are much better ways to pass data around than with a FGV.  Even a simple Global Variable I would argue is better than this implementation of a FGV (only Set and Get states). See this article for more information about what I'm getting at: A Look At Race Conditions.