why does the vi crash when i add the less than part in the loop?

[1231]

hi everyone and thanks for the help here, i want this particular vi to stop when v is less than 2.5 volts, i added the block and i got an error.....

see the document?

weird, it works when i put in a button to stop the program.

[nyc_(is_out_of_here)]

I can't see the entire error message, but it looks like LabVIEW is complaining about the input to the Scan From String element.