Hello,
Thank you for contacting National Instruments.
I took a look at your VI. I think the problem may be that you are using a Continue if True loop condition in your first While Loop. If you press the stop button wired to this condition or if an error is generated in your VI, that first loop will continue to run indefinitely. Try right clicking the loop conditional and changing it to Stop if True. You may then need to change your Less? function to a Greater? function within that same loop to preserve the intended behavior of your program
I hope this solves your problem. If not, let me know.
Matthew C
Applications Engineer
National Instruments