What is the Stop boolean wired to and when is it read?
If the switch is wired to the Stop terminal of a While loop, it doesn't stop the VI instantly: it stops it at the end of the current iteration. It the Stop button isn't wired anywhere, it doesn't do anything: it's just a boolean with a label=Stop.
A boolean switch will operate unless it is disabled. You can disable or enable the switch programatically using a property node or from the front panel (right-click on the control, then select Advanced >> Enabled State, then select Enabled or a Disabled option. All boolean switches on the control palette are enabled by default.
The default mechanical action for the Stop boolean is Latch when released: after you release the switch (raise your finger off the mouse
button), the switch will return to its default as soon as it's read. So if the switch is being read in a fast loop, you might not be able to see it go TRUE, but you code will (if you have it wired correctly).
If you verify that the switch is enabled and that it is wired correctly and still can't see the problem, can you post your VI?
