pressure switch

system · January 5, 2003, 9:22pm

where should we put our pressure switches for it to turn the compressor on and off?
it seems like it is attached on the pressure tanks in the pneumatics manual, but how is it going to be able to turn the compressor on and off from there? or does it matter where it is placed?

rbayer · January 5, 2003, 9:29pm

The pressure switch does not turn off the compressor by itself, it merely lets the software know when the tanks are full so that the SOFTWARE can turn off the pump.

Jon_Lawton · January 5, 2003, 10:18pm

rbayer is correct. DO NOT connect the pressure switch in series (directly to) the compressor! You will break your pressure switch. Instead, connect the switch to the Digital Inputs on the Robot Controller as per page 13 of “The Robot” section of the manual. The pressure switch can be located physically anywhere before the 60 PSI regulator. Most teams put it on their reservoir (air tank).

system · January 5, 2003, 11:28pm

okay thanks a lot

RobDeCotiis · January 29, 2003, 9:20am

we have our pressure switch connected directly through a relay going to the pump… the pressure switch cuts power to the relay, the relay cuts power to the pump… only problem is that it shuts off about 115 and goes back on at like 95… any way to fix this?

RobDeCotiis · January 29, 2003, 9:28am

also, are we allowed to code it in so that it stops at 125 or so and re-opens at 115? stopping at 115 and re-opening at 95 is making us lose that extra 10 psi… and with our massive pistons, that’s a lot.

Hendrix · January 29, 2003, 9:50am

Actually those settings are hard coded to the switch this year…

Greg_Ross · January 30, 2003, 2:20am

*Originally posted by RobDeCotiis *
**also, are we allowed to code it in so that it stops at 125 or so and re-opens at 115? stopping at 115 and re-opening at 95 is making us lose that extra 10 psi… and with our massive pistons, that’s a lot. **

The maximum allowed system pressure is 120 psi, so I wouldn’t recommend trying to get it up to 125 psi, and I don’t believe there will be any discernible difference between 115 and 120 psi.

That being said though, you can use code similar to what we used the last two years. Just figure out how long it takes your compressor to raise the system pressure from 115 to 120, and after the pressure switch opens, continue running the compressor for that long.

rbayer · January 30, 2003, 9:12pm

*Originally posted by RobDeCotiis *
**we have our pressure switch connected directly through a relay going to the pump… the pressure switch cuts power to the relay, the relay cuts power to the pump… only problem is that it shuts off about 115 and goes back on at like 95… any way to fix this? **

This is NOT a legal (or safe) way of doing it. The pressure switches just aren’t designed to handle all the current drawn by the compressor and relay. You MUST use the switch to control the relay from within the software.

DougHogg · January 31, 2003, 3:16am

Last year, we had 2 pressure switches. We used one to turn off the compressor and the other one to turn it back on. So far I have only seen one this year. Are we missing one? If not, any idea on the best way to program the robot for just one pressure switch?

D.Viddy · January 31, 2003, 3:52am

There is only a single because the one switch acts as two switches. It opens as 115 and it closes at 95 or something like that. So it can easily be programmed like it were two.