Please Help need quick answer :)

[mcf747]

Hey everyone I hope everyone is having fun with their pneumatics as we are, but 3 really pressing questions here.

1) Where can I get spare/replacement for the SMC Double Solenoid Valve?
(Someone was working with a mallet near my pneumatics and well... the valve lost)

2) Is anyone willing to give or trade their valve(s) (should have received 2) we will pay for shipping.

3) I have saw some posts on this already, but my safety valve seems to also be set incorrectly. I have tested just a valve and some of the other safety features like the manual bleed and the sensor that goes to the robot interface in a controlled environment and have taken the pressure up to over 160 psi and the valve will still not budge I am submitting an official rule clarification to FIRST about the "do not modify rule" but want to here what everyone else has decided to do.

Thanks for the help,
Matthew
FRC1515

[dtengineering]

I'd contact a local distributor:

http://www.smcusa.com/smcusa/contact.aspx?stateid=6

Or a nearby veteran team.

As for the safety valve, good on' ya' for putting in the Q&A. It is an undetectable fix that improves robot safety, but may as well get it approved by the GDC first. Either that or fix it under the watchful eye of a tech inspector at the competition... but it hardly makes sense to wait in order to make a safety improvement.

Jason

[Clifford]

Perhaps I should have asked FIRST first?

[jee7s]

The inoperable pressure switch could be explained by wiring. Last year, we found the switch needs to be pulled up with a resistor (100K or so) in order to give a proper signal. This way, the controller sees 5V when the switch is open, and ground when it is closed.

Without the pullup, you get ground and high Z (read "floating")..which is an indeterminate state. The controller won't see a state change no matter what you do...so the tanks over charge. (NB: The switch doesn't turn off at exactly 120psi, but usually a little bit more.)

-JEE

[usbcd36]

The robot controller's digital pins are pulled high internally. In order to make the pressure switch work, you need only connect the ground and signal wires of the PWM cable to the two screws on the pressure switch. Cap the red +5v wire and don't connect it to anything.

Furthermore, the safety valve and pressure switch are two different things. The safety valve should let air out of the system when the pressure exceeds 125 PSI.

[mlucas]

We have a bad pressure switch from a few years back, 2006 I believe, maybe you just got the duds? Be sure you have it connected to the Digital in and that your programming is correct. IF using EasyC, there is a block that all you do is input the digital input port, and the output for the spike...just my 2and a half cents

[DonRotolo]

Originally Posted by jee7s

The inoperable pressure switch could be explained by wiring.

Originally Posted by mcf747

3) I have saw some posts on this already, but my safety valve seems to also be set incorrectly.

Safety Valve, not pressure switch.... I agree that the switch might be set for a little bit off from 120 PSI. The safety valve is passive and really should 'pop' off at 125 PSI or so.

After reading a few posts on the issue, I will have the team test the valve we're using, just for safety's sake. We've never had a problem, but the function of that valve is a critical parameter.

Don

[MrForbes]

we should test ours too....the pressure switch works fine, and we never tried to get the system over 115 psi.

Last year our safety valve was loose "out of the box" and we adjusted it and didn't think much of it. I guess it's rocket surgery, though....so if it's not working right, quickly ask for a replacement from FIRST?