Vin is the output from a variety of instruments, most pre-fab (ie., black boxes) that include pressure, flow, and temperature transmitters. I've been tasked to "back into" this project which has already been sent to fab and I'm supposed to make it work. I starting in the middle and working to both ends, making it work and figuring out why it was designed the way it was. I have decent design notes, but deciphering what was designed and realizing an error was made and where the error is are definately distant but related tasks.
I can't quite figure out how to use 330k and 2.2m resistors to get the proper threshold. Substituting them directly, raised the upper threshold over 250mV.