Pneumatics, solenoids and frustration

Technical Java
1

I’m no novice with the wpilibj or Java. I know how most of it works, and the logic required to do almost any task. The thing is, my team has never touched pneumatics. We just didn’t need it. So I’ve become very frustrated lately because I’ve found it extremely challenging to get them to work.

The two things we’re doing:

  1. Gear shifting using supershifters
  2. Loading with a solenoid actuated piston

So its not rocket science.

So far, I’ve been able to actuate the two sides of solenoids (ones provided in KOP by festo), verified by the lights turning on. I’ve also been able to switch the output of the solenoid twice, once on both systems, but seem to be incapable of doing it again. It seems to be complete luck.

Our current method to turn solenoids on and off (simplified for readability):


Solenoid s1 = new Solenoid(1);
Solenoid s2 = new Solenoid(2);
boolean shooting = false;

…


if(controller.getAButton() && !shooting) {
    shooting = true;
    s1.set(true);
    s2.set(false);
    Timer.delay(1.5);
    s1.set(false);
} else if(!controller.getAButton()) {
    shooting = false;
}

This seems to be correct. We have used the manual releases in a very similar way, and have gotten the solenoid to work. As for electrical, the lights show, and we’ve measured the output to 24v.

Now I know it looks as though it’s the solenoid. But we have tried 3 different, OOTB solenoids.

I’d be happy to take pictures of the wiring if needed, or provide more context to the code. We’re using a festo piston (couldn’t find model number, just a standard festo one) and solenoid (VUVG-L10-B52-T-M7-1P3 –1).

2

Are the solenoid module indicator lights turning on/off as you expect?
That will tell you that your code is working correctly and isolate the problem to wiring <-or-> code.

Is the solenoid valve pressurized?
The KOP Festo solenoids are driven by a minimum pilot pressure of 25psi.

3

The solenoid module indicator lights do turn on and off as expected.

The solenoid valve is pressurized.
We always wait until 60-120psi.

4

Since your code is good, as evidenced by the module LEDs, and you have the required pilot pressure…

You checked the Breakout voltage, so the other possibility that occurs to me is that the solenoid wire pair are reversed where they plug in to the Solenoid Breakout.
ground <-> signal

Try reversing the 2-pin connector to see if that helps.

It won’t hurt the solenoid to plug it in backwards, but the light on it can still come on.

5

We’ve tried reversing the cables, and the lights did not turn on when we did.

6

Check the manual triggers on the solenoid.
They can be pushed to momentarily test the solenoid, or turned with a small screwdriver to lock them in place. If in the lock position the solenoid won’t respond.

For normal operation both of the slots in the blue buttons should be oriented along the length of the solenoid body.

If they are perpendicular or sideways to the body then the solenoid won’t respond.

You can just see the slots here:

7

The manual triggers work. They are in horizontal position (like the picture).

We’ve tried it on 3 different solenoids, none of them working.

8

Only other thing I can think of is if the coils aren’t seated properly on the solenoid ends. That’s a stretch though.

9

That is where my frustration is. I just can’t seem to trace what we’re doing wrong. I guess we will just continue to try different setups out until we get it working.

10

Is it possible that I should be turning both sides off to let air through? Was a suggestion from a teammate.

11

For normal operation, you should only energize 1 of the solenoid coils on a given solenoid valve at a time.

12

My life is saved! It turns out the problem was that it was wired for 12v, not 24v. Our electrical person was being stupid. :smiley:

13

He or she needs glasses if they thought a 12v reading on a multimeter was 24v :yikes:
They suffer from double vision…

14

I agree. Maybe somebody was messing with him. :stuck_out_tongue: