Pneumatics...

nadavsen2 · January 19, 2010, 4:16pm

We are using pneumatics for the first time and i don’t have any idea how
to “connect” the code with the it. Is there a manual about it or some guide?

thanks a lot

Mark_McLeod · January 19, 2010, 4:28pm

FIRST publishes a Pneumatics Manual every year to get you started.

We have some pneumatic guides posted on our website to help. The Pneumatics Step-By-Step (for the cRIO Controller)](http://www.team358.org/files/pneumatic/Pneumatics-StepByStep-cRIOversion.doc) has code examples.

The Fluid Power Educational Foundation has some training information.

Here’s a Pneumatic Power Concepts presentation done by Raul Olivera at the Championships in 2008.

A big issue is getting yourself some fittings to use with the tubing. They are essential parts that haven’t been supplied in the KOP for the last couple of years. We had a rookie team visit us last night to pickup some fittings, so they could get their pneumatic system up and running.

nadavsen2 · January 20, 2010, 2:28am

wow , thanks

ebarker · January 20, 2010, 8:53am

New question - same thread.

Can we use 24VDC actuated valves instead of 12VDC valves. Doesn’t the cRio drive 24VDC now ?

Mark_McLeod · January 20, 2010, 9:00am

Yes, you can use both 12v and 24v solenoids this year.
The wiring permitted by FIRST allows for a possible (8) 24v coils and/or up to (30) 12v coils - just not all at the same time.
One coil is one single solenoid or half a double solenoid.

ebarker · January 20, 2010, 9:34am

wow - that opens up a whole new world of parts that are available on the shelf - at least from my suppliers.

is there any special jumpers or anything on the solenoid driver to setup to use 24VDC ?

a few things

great site at 358
didn’t know allied electronics did pneumatics
broken link to a alliedelec page off the 358 site, it points to a page of leds
the fluid power site seems to have too many broken and incorrect links - someone needs to go through the site and make a punch list to send them ( in a very very nice way of course )

Mark_McLeod · January 20, 2010, 9:43am

Thanks for the feedback.
I’ll pass the broken link info along and it’ll get fixed tonight.
The pdf documents are getting a slight rewrite based on the latest rules & code revisions too.

The Fluid Power site hasn’t been well maintained for awhile, but I like to include a plug for them since they support FIRST.

The 24v change opens up 5 cases of donated solenoids I had languishing in the shop.

ebarker · January 20, 2010, 9:50am

One more thing - I need a supplier of pneumatic solenoid valves, 3 way and 4 way, Cv 0.30 or so. Ideally it would be a single pair of wires, one solenoid, like the Festo we had a few years back. It seems to be difficult to narrow down vendors.

and one more one more thing - what is the Festo part number in this year KOP ?

Vikesrock · January 20, 2010, 10:31am

To get 24VDC out of the solenoid breakout you put 24V from the cRIO port of the Power Distribution Board into it.

EDIT: Also I’m definitely a pneumatics newbie but I don’t understand one of the concepts in the Pneumatics for Newbies guide on the Team 358 website. The guide suggests that you would be able to run a 2"x12" cylinder (38cu in. at 60PSI) off of a single accumulator (listed as 18.5 cu in @120PSI) once. While this would be true if you could evacuate all the air from the accumulator and send it into the cylinder, in actuality can’t you only run a 2"x6" cylinder once at the full 60PSI? After running this cylinder once the volume of air in the accumulator would be cut in half so the pressure should be cut in half as well, right?

Lakedaimon · January 20, 2010, 12:26pm

So this explains why we have not gotten the parts to get the pneumatics system working. I thought that the fittings had just somehow been left out of our KOP last year (and also the checklist.) I was thinking we would get some this year, and was surprised and frustrated to find that they were missing again (we are a second year team this year, so we’ve never gotten any.) So… if anyone can give some advice on what we should buy and where is the best place to get it, it would be much appreciated!

IndySam · January 20, 2010, 12:32pm

If you can find a veteran team in your area. Odds are they will have lots off fittings on hand.

Mark_McLeod · January 20, 2010, 1:40pm

Yes, you’re quite correct. Only 18.5 cu in of air are available at 60 psi from one of the Clippards at 120psi. Unless you use the vampiric, suck 'em dry, mechanism…
I also see that there are several unfinished notes that should be fleshed out. Senioritis obviously set in - both mine and my students.
Thanks.

P.S. Ed, I’ll have to check on those.

artdutra04 · January 20, 2010, 2:50pm

Not receiving any push-to-connect fittings in the KoP was (for me) the same as not giving teams one official soccer ball in the KoP: a somewhat inexpensive gesture that could have alleviated most teams from having to track down a really obscure component. Anyway, after searching high and low among various suppliers online, we found that Automation Direct had the best prices on COTS push-to-connect fittings. (If you want the cheapest, just search eBay for “push to connect”).

Here’s links to all the various 150PSI, 1/4" tube, push-to-connect fittings that may be useful, the bold ones especially so:

Either meter-in (slows air into the pneumatic cylinder) or meter-out (slows air coming out of the cylinder) works, just be sure to keep it consistent. Back when push-to-connect fittings were in the Kit of Parts, teams were given meter-out fittings.

Lakedaimon · January 20, 2010, 5:57pm

Fantastic response Artdutra04, thanks!

Mark_McLeod · January 20, 2010, 10:47pm

It’s Festo part # VUVG-L10-B52-T-M7-1P3
Documentation
Datasheet

M7 fittings…

jerry_w · January 21, 2010, 11:09am

I wince when I read about the 24 volt solenoids. In the real world, this would be considered a very bad design decision.
The 24-volt supply provides stable power to the controlling computer. Attaching switched coils to this supply guarantees that transients will occur during operation. Although the crio has protection agains damage, there is the risk of program interruption. In the worst case, the controller would have memory corrupted. More likely is the activation of a reset.
I recommend that teams avoid the use of the 24 volt solenoids, although that is the industry standard. Please, don’t give the programming team members any more problems to deal with.