Actually, I would warn against using Globals in LabVIEW. LabVIEW will actually avoid race conditions by automatically pausing the program to allow everything that needs to write to it to do so before anything can read. This can cause
massive slowdowns, as well as otherwise inexplicable pauses in the code.
If you really need to communicate across VIs, make a VI whose only purpose is to serve and receive a value, as follows:
Code:
Indicator - Control