How to end a single the second time a value is reached

Hi all,

I have a resultant signal, and I am trying to figure out how to automate my code to end the signal after the second time it achieves a value less than X.

So, signal is going from 0 to 4.2volts (peak), then I want to end the signal once it is under 0.6v. I want to be able to get the numerical integration under the curve for my peak signal(which ranges from 0 to <0.6v).