[BradAMiller]

The InitPressureSwitch function causes the timer interrupt service routine to read the pressure sensor every millisecond (probably overkill, but it was an easy place to put it). If the pressure is low the supplied relay port will be turned on, and if it's high it will be turned off.

So you only need to call the function once, and for the rest of your program, both autonomous and operator control the compressor will operate on its own.