On page 4 of the previously mentioned pneumatics manual:
http://www2.usfirst.org/2003comp/pne...anual_2003.pdf
the description of the components clearly state the pressures used. It looks like we have an initial pressure switch to tell the Robot Controller when to shut off the compressor, and a system (after the air tank) regulator which must be set no higher than 60 lbs. There is another regulator you can use after the system regulator if part of your system needs even lower pressure.