(Hopefully) All you need to know about Pneumatics

[RyanN]

As I can see, there are many posts right now being posted about the Pneumatics tonight. This will hopefully ease some of the confusion.

First off, pneumatics are NOT complicated. Keep this in mind when working with them. In fact, they're one of the easiest things to get working as long as you follow the basics.

Please leave comments, suggestions, or must-have tips here. Please DO NOT ask any questions in this thread. This is meant strictly for reference.

[RyanN]

Compressor:
Ah, the compressor. The heart of your robot's pneumatic system. It's function is simple: compress the air and push it to the accumulators. It is controlled by the pressure switch. Before you shoot off and wire it up, follow these rules and tips.

First off, the compressor has to be controlled by the robot controller and nothing else. The compressor is powered through a Spike relay module and protected by a 20A circuit breaker. The minimum wire size allowed is 18AWG, but I prefer 14AWG because of the high starting current of the compressor, especially on an already charged system. Also, pop out that yellow fuse and put in a 20A circuit breaker. The high starting current of the compressor is known to blow the fuse. It WILL happen if you don't replace it, and the worst time to discover this is during a match.

So now you should have your Spike with the 20A breaker, some 14AWG wire, and another 20A breaker. You'll also need some female quick connects to wire it up to the spike (4 total.) Wiring the compressor is very simple. The red wire from the compressor goes to M+ on the Spike. The black wire from the compressor goes to the M- on the Spike.

Now wire the Spike to the Power Distribution Board (PDB). The 12V will connect to a red tap on the PDB with the breaker rating at 30A max. Wire the GND to a black tap next to the red tap you just wired up. Plug the other 20A breaker you have into the spot you just wired.

Power on the system. The Spike should light up orange, but the compressor will NOT run yet.

Find a PWM cable and connect the Spike to the Relay 1 port of your Sidecar. You may pick another port if you're team is confident in programming. Make sure everything is connected properly. (SIG should go to the white wire, (-) should go to the black wire. The black wire is labeled on the Spike.), otherwise you won't be able to control your compressor.

Refer to the PDF below for an image representation:
Compressor Wiring.pdf

[RyanN]

Pressure Switch:
Now that you have your compressor properly wired and tested, let's try to control it using the pressure switch. This part is easy, and should not take more than a few minutes to complete.

First, get a PWM cable (if you have one with broken pins on the male end, then great!), two small gauge (Red) ring terminals, and your pressure switch.

Next, cut off the male end. You can discard it or save it as you wish. Strip back the wire and attach the ring terminals to the white and black wires. The red wire will remain unwired, and you are encouraged to trim it off. Hook one ring terminal to one side of the pressure switch, and the other ring terminal to the other side. Then plug it into Digital I/O 1. You may pick another port if you're team is confident in programming.

Refer to the PDF below for an image representation:
Pressure Switch.pdf

[RyanN]

Solenoids:
So now you have the heart and the brain of the pneumatic system up and running. Great! Now you have a few things you want to control, right? I sure hope so!

So the solenoids are the valves that control the stored air in your robot. Want to extend a piston on command? Then you need a solenoid.

There are currently two flavors of solenoids, 12V and 24V. Since the year is 2010, and teams are using 24V solenoids, then I'll talk about how to wire them up.

In the kit, you were provided with two-wire jumper cables, a solenoid breakout module, and the solenoid(s).

If your team decides to use the 24V solenoids, you will want to wire the solenoid breakout module to the cRIO's power connection. This is the ONLY time where you're allowed to connect anything else to the cRIO's power feed. Make sure to get the polarity right, and plug it all in. Turn everything on and verify the power light on the solenoid breakout comes on, along with everything else.

Then, cut your two-wire jumper cables in half. That way, you have 2 cables to use instead of 1. Extend the cables with 24AWG or larger wire. Make sure to keep the polarity correct or the solenoid's won't work. Wire them directly to the solenoid.

You should now be able to control the solenoids in the programming.

You will go from the solenoid directly to the Solenoid breakout (pictured below.)


The solenoid breakout plugs directly into the NI 9472 Digital Output Module:

[RyanN]

Hoses and General information:
Now that you have everything wired to your pneumatic system, it's time to connect the hoses.

The best way to do this is to follow the Pneumatics Manual that FIRST has provided. Particularly, page 10 for the picture representation.

Remember to set the low pressure side to 60PSI or lower. Check for leaks. I recommend some foaming soap (such as Dawn Foam). Be sure to keep the soap away from electronics though! I recommend foaming soap over soapy water because the soap will not run and drip as bad.

Keep the release valve in an easy to access place.

Wrap screwed in connections with Teflon tape. Be sure to wrap it in the right direction, and do not put too much Teflon on the connections. To wrap it correctly, hold the part with the threads facing away from you, then turn clockwise while wrapping the Teflon. This way, the Teflon stays in place when you screw it into something.

Refer to 2010's R72-R79 for rules regarding pneumatics.

[Gary Dillard]

How Many Tanks do You Need?

Check out this post for the math.

[buildmaster5000]

team 358 has a number of great resources to solve all pnuematic issues

http://www.team358.org/files/pneumatic/