Hello, is there a limit (and if so, what is it) of cylinders that my team can use in the pneumatic system? Also, is there a maximum length for our cylinders? And finally, can we connect two cylinders to the same electric valve for the competition?
No legal limit in quantity or length, though there may be some practical limits, like robot weight, fitting in the frame perimeter, and only having so much air.
Yes, you can split a solenoid valves output to multiple cylinders, but you can’t plumb the output of two solenoid valves together (R94).
Read the pneumatics rules R81 through R94. They’re all about keeping things from literally blowing up. Read them several times.
Further to this… With good reason the LRI and RIs are very very picky about the pneumatic rules. If you do not follow them exactly they will require you to address it before you pass Tech inspection. R85 specifies the exact legal pneumatic circuit. That is the only legal circuit. R85B requires the Pressure Relief Valve to be directly connected to the Compressor via rigid fittings (ie no flexible tubing between them).
Pay special attention to R83 as that trips up teams. You cannot modify mounts to better work in your design. The only legal thing you can do to a mount is choose not to use parts of it (if it is a multipart mount). You cannot paint tanks or cylinders. I have heard this rule getting interpreted to mean you cannot wrap the tanks to attempt to colour them.
I didn’t see anything about this in the rules, but are we allowed to put a spacer over the piston rod in such that when it retracts it doesn’t go all the way down?
It’s not in the rules, so yes you can.
Agreed, yes you can limit the travel through stops. Don’t use a shaft collar or other means which attaches to the moving section of the shaft if you plan to use that cylinder again; it takes surprisingly little damage to the shaft to create a sticking point or worse.