The working pressure for the robot would be 60 psi. See the Pnumatics manual under "regulators."
http://www.usfirst.org/uploadedFiles...ics_Manual.pdf
The pressure switch will turn off the compressor at 115-120 psi. The accumulators will have that much pressure in them. The actuators cannot run at 115-120 psi. That is what the pressure regulator is for. It MUST be placed BEFORE ALL working componnents on the robot. It only lets 0-60 psi through to the actuators.
As for the pressure switch, I don't know, sorry.
Good luck,
Jacob