filling pneumatic cylinder

VEX V5 General Discussion Technical Discussion
#1

We recently came into possession of a used pneumatics kit. All the pieces are present and accounted for, and we connected the pieces in a configuration similar to the diagram shown on the product page, and we think we have the programming/control OK (the solenoid “clicks” when we’re expecting it to).

However, we’re having trouble filling the reservoir. We’re attaching the pump to the tire pump fitting, with the on/off switch closed. We’ve tried pumping with both the orange plug for cylinder in and out, but air doesn’t seem be accumulating in the cylinder, so when we open the on/off switch, there’s no pressure transmitted to the cylinders. We’ve been paranoid about overpumping (no gauge on our pump), but I’m sure that we’re not anywhere close to 100 psi.

Also, is there any official documentation? We’ve seen the FAQ’s in the forum, but on the product page, there is no documentation link to the Inventor’s Guide page. Come to think of it, links to Inventor’s Guide pages seem to have been removed for other products, too (like the tank tread kits, etc.), and they aren’t on the wiki pages, either.

Lastly, to control the cylinders using the transmitter, we’re using GetRxInput to read the joystick position from the transmitter, then using it to set the digital output to 1 or 0. We were wondering if there is a more elegant solution.

#2

First guess from me is that the air is leaking out through hose fittings between the cylinder and the solenoid. That was what happen to us originally.

Try submerging all the part or at least the parts that can survive getting wet.

Try listening very carefully.

Try the soapy water method.

Etc.

#3

Make sure that all the tubing is cut perfectly level. You’ll get the best seal this way and you might spend half an event wondering why your pneumatics doesn’t hold a charge and then you realize there’s a tiny leak caused by a tiny bump in your pneumatic tubing. Not that I’m speaking from experience or anything.

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#4

Yep, it was leakage all right – not just in one connection but (at least) 5. Air was leaking out of so many places at once that we couldn’t hear it. Fundamentally, we didn’t connect the tubing correctly – just pushed it in, instead of locking in by squeezing the bushings on the end. It took a while to figure out that the pressure value should be tightened, too.

The good news – it works!

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#5