Pneumatic Help

Technical Pneumatics
1

Hello, our team this year incorporated the pcm onto our robot and we are having a problem. We know the code and everything is updated to what it needs to be. So the problem, the solenoid will work when activate but then at random times stop working. We restart the robot and everything works again perfectly fine but after a while it stops again. The PCM will start blinking red when the problem occur. After going on the WebBoard their was a solenoid fuse sticky. When I would clear it their by double tapping self- test it works again but the problems come back again after a minute. Does anyone know how to solve this problem. Any help will be much appreciated

2

Sounds like your solenoid is overdrawing the PCM. Make sure.
1)the 12/24 volt jumper on the PCM is set to match the valve.
2) The current specifications of the solenoid matches the PCM.
3) You don’t have a short in the wiring. A little whisker on a connection can do it.

3

We have done all of these steps based off of other post but it still doesn’t work. We have check the wiring and it seems to be correct.

4

Does it always occur with the same solenoid?
Do you have other solenoids on the robot where it doesn’t happen?
Do you have a different solenoid that you could try in case it’s just the solenoid?

5

We are using 6 solenoids on 1 pcm.

It does not happen on the same solenoids. It randomly switches to the ones that work and don’t.

We have some spares we can try if it is the solenoids

6

Possibly, it could be exceeding the total solenoid sum of all channels draw of 500mA that makes it appear as if the fault is moving around to different solenoids.
One or more solenoids pulling more than 90ma could cause the trip I suppose.
Although I assume you are only ever firing 3 of the PCM solenoid outputs at the same time.

7

http://www.humphrey-products.com/product-page/310-single-solenoid-valve-series

This is what were are using is their a possible fix to this

8

That appears to be the problem.
If they are all on then those single solenoids will pull:
12v model = 333ma * 6=2000 ma
24v model = 167ma *6=1000 ma

Some possible solutions:

  • Don’t allow more than three or so solenoids to be energized at the same time in the code (might be accomplished by reversing some of the tubing directions, so that some go off as others get turned on)
  • Add a second PCM to spread out the load
  • Shop for or borrow solenoids that don’t require so much energy.