Is it necessary to put two pressure switch on the pneumatics system or just one? 
One is enough.
But 2 is necessary to have a efficent system, one set to system low and another set to system high, this will prevent unecessary cycling of the pump, and save some breakers 
You can and according to the manual, you should put two onā¦one for each accumulator. You run it so that the 115 psi switch is on the first accumulator on the line, and 110 on the second. You then program it so that when it sets off the 115 psi switch, the pump turns off, then when the 110 psi switch is released, the pump starts back upā¦
I would also pre-pressurize the tanks before matches.
I donāt thinks the switch is required. Also, you donāt necessarily need to have 2 switches to have an efficient system.
It is possible to write code that runs the pump for XXX seconds after the switch is made. We set the switch to 100 psi or so. Then we measure how long it takes the pump to get to 120 psi after the switch makes its transition to indicate the pressure is above 100 psi. We then use the delayed turn off code to keep the pump running until the pressure is at 120 psi.
Joe J.
One of the top robots at the Canadian Regional (who only received ONE switch) have the switch show the operator (via the SW1 LED on the OI) when the pressure is low, and then he holds a button down until the light goes out.
I had shown them the code for counting time that we used last year, but they simplified it some .
āUncomplicated may win !ā parlayed the paraphrased playful Pappalardo Professor.
I dunno, our method didnāt seem too complecated to me, and thereās no guesstimating and operator involvementā¦i like those ideas though.
You could set the one switch to 120 psi. Then use the program to debounce the pressure switch. When the switch first indicates that the pressure is at 120 or above, use a counter variable to wait 1 sec (roughly 40 cycles of the main loop) before turning the pump off. Use the same delay before turning on the pump after the pessure drops below 120.
The benefit of having two switches is ease of programming. With them both connected to the accumulators, if you set one at 120 psi and the other at 100 psi you can program the compressor to turn on when the pressure dropps below 100 and shut off when the pressure gets to 120 psi. This way you donāt have to do any ādebouncingā.
Last year we had problems blowing fuses on the spikes if we turned the compressor on with an accumulator pressure at 120 psi. It didnāt happen very often but I believe it is good practice to not turn your compressor on unless the accumulator pressure is less than 100 psi. The easiest way to do this is with two switches. The method Joe J. mentions is also a good one but is probbably a little trickier to program. The method described by āThe Lucasā allows the compressor to turn on at high pressures if you have a slow leak or a small cylinder.
the less our driver has to think the better, 2 switches is what we feel is best, no thinking required.
We use the one switch + delay that Joe mentioned. It works fine, less parts, one less input, and the code is easy enough.
Prior to this year, we only had the one switch to work with. Itās one of those āIt aināt broke - donāt fix itā things for us.