On Jul 1, 5:20*pm, "Buerste" wrote:
I have some air circuits that are controlled by cams that actuate manual air
valves that look like limit switches with roller arms that follow the cam..
Would I be better off with electric limit switches on the cams and use
electric air valves? *The cam rotates at 120 rpm. *The dwell on the switch
is 45 degrees.

I do have to replace the air switches every 2 years or so.

I will NOT install a PLC or anything more complex.

I have a similar application coming up and will need to use electric relays
to control air valves *or air piloted valves to control air valves. *Which
is more reliable? *I do have really clean, dry air.

Use electrical. It's far easier to service and you should get at least
5 years (probably more) out of the cams/micro-switches. This was a
standard Honeywell method and I always found it worked well, was easy
to adjust, and fault finding with a meter was easy. Don't screw around
with optical / position sensors - you'll spend more time fixing those.