How to breaks an endless loop with an external command of my device object (analog input) ?

Hello. I am acquiring data, in my code there is an ai.triggerRepeat defined as Inf, and my while loop: while i == triggerRepeat I need to stop may ai.triggerRepeat with an external command and then stop my while loop, but I can do it when I enter into a while loop it does not stop. How can I introduce a external command that can stop my loop.

Thanks a lot.