Vex pnumatics problem

My team had put pnumatics on our robot and we are not getting the correct amount of shots from our pistons. We have checked for leaks and we fixed them all. We have one tank and the exact setup that vex requires we get about 6 strokes of the piston an te tank is filled to 165PSI. Does anybody know how to make the pressure last longer and get it to the max amount of strokes out of our pistons

Could you elaborate further on your problem?

Do you mean that the piston is getting 6 solid shots then stopping altogether or that the piston is getting visibly weaker every shot until not extending at all on the 7th shot?

Which type of piston are you using?

Can you provide a picture of your whole setup including tubing procedure?

It gradually gets weaker until the 7th shot then doesn’t have any air left. I’m using dual action pistons and they get a full extention and retraction I will post pictures when I get the chance

How much tubing are you using between the solenoid and the connections to the piston ?

Excessive tubing between your solenoid and your piston will cause you to consume more of your usable pressure.

What is the highest psi you’re allowed to have at the VEX events?

100 PSI is the maximum.

Okay I might, and i was just wondering because he said his was at 165.

Regarding PSI:

Here’s the datasheet for double-acting piston:

Notice where it says “proof pressure” is only 145 PSI, and the maximum operating pressure is 100PSI. This means, that if you apply more than 145 PSI to the piston, you will change the specifications (and, if my understanding is correct, possibly cause damage to the device). Also, as far as I can tell, no pneumatic component in the VEX system releases excess pressure to protect the piston when people overcharge their systems.

The upper limit of 100PSI for system pressure is there for a reason, people. Please don’t kill your expensive pneumatics for a couple more strokes.

Also, note in the [Inventor’s Guide entry that you can only expect to get ~45 strokes from a single reservoir.

Since these are double-acting, that reduces to ~22 strokes in/out. Since you’re using two pistons, this further shrinks to 11 operations per piston. You’re not getting the output you should expect, but this is just to give a realistic expectation of how few strokes you can get.


check the setting on the regulator. if it should be adjusted so that there is just enough pressure to the piston to do what it needs to do but not more or you are just releasing air for no reason.

Is it legal to have 2 reservoirs correct?

Wow, you revived a really old thread.

Here’s a link to the current game manual so you can look these things up:

and here’s the relevant rule:

<R18> Pneumatic devices may only be charged to a maximum of 100 psi. Teams may only use a
maximum of two (2) legal VEX pneumatic air reservoirs on a Robot.