[Ryan Cumings]

I entirely missed <R54>
The wording makes it a bit tricky from a strictly legeal stand point. However with the whole spirit of the game, I think the rule is trying to make sure that you do not hook the pressure sensor directly inline with the compressor.

The pneumatics manual hints at this under the section they designate for the pressure switch. It also says that there is no control in the default program to control the relay so I suppose it goes to say that you can control the relay however you want, just as long as it is done entirely in the code.