To amplify Alan's comments, it is easy.
The compressor is either on or off, nothing in-between. You control it according to a "switch" that goes to a digital input. If the switch is "on" the compressor is off, and if it's "off" the compressor is on.
Easy enough, right? Be sure to read the rules when they come out though.
To actually control a pneumatic piston or something, you turn the "solenoid driver" output on or off. Again, quite simple. The design group will tell you what has to happen to turn "solenoid number X" on, or off.
The rest is the mechanical team's problem.
