Exhaust in Solenoids

[Mark McLeod]

Originally Posted by FTC Team CC

Does activated mean open or closed valve?

You can think of the one solenoid as two valves that always do the opposite of each other, or as a single value with two positions.
In one position (deactivated), it is trying to fill one end of a cylinder (let's call it cylinder end A) by sending pressurized air out port A, simultaneously it is trying to empty the other end of the cylinder (let's call it cylinder end B) by releasing the other pressurized end out an exhaust port.

In the opposite position (activated), it reverses the cylinder action by sending pressurized air through port B to fill cylinder end B, while simultaneously emptying cylinder end A by connecting port A to an exhaust port.

[FRC Team CC]

Originally Posted by Mark McLeod

You can think of the one solenoid as two valves that always do the opposite of each other, or as a single value with two positions.
In one position (deactivated), it is trying to fill one end of a cylinder (let's call it cylinder end A) by sending pressurized air out port A, simultaneously it is trying to empty the other end of the cylinder (let's call it cylinder end B) by releasing the other pressurized end out an exhaust port.

In the opposite position (activated), it reverses the cylinder action by sending pressurized air through port B to fill cylinder end B, while simultaneously emptying cylinder end A by connecting port A to an exhaust port.

We tested it out, and we have no control over any of the valves, even though we used the same code mentioned above and the solenoids are lighting up...

[FRC Team CC]

Do we need to manually lock the solenoids to property use it (the lock mechanism is the blue screw)?

[Mark McLeod]

Originally Posted by FTC Team CC

Do we need to manually lock the solenoids to property use it (the lock mechanism is the blue screw)?

No, it must be unlocked to work.
You can temporarily press the blue button to test, but don't twist and lock it.

[headlight]

No, the blue screw is a way to manually activate the solenoid valve. Unless it is pushed down or set in the lock position it shouldn't stop you from controlling it. A picture of your entire setup might be helpful.

Here is a link to the series catalog for your solenoid, it might give you some helpful information. http://content2.smcetech.com/pdf/SY3.5.7.9000.pdf

[FRC Team CC]

Originally Posted by headlight

No, the blue screw is a way to manually activate the solenoid valve. Unless it is pushed down or set in the lock position it shouldn't stop you from controlling it. A picture of your entire setup might be helpful.

Here is a link to the series catalog for your solenoid, it might give you some helpful information. http://content2.smcetech.com/pdf/SY3.5.7.9000.pdf

Here is a picture of our setup:
http://imgur.com/a/Wwh4t

[GeeTwo]

Originally Posted by FTC Team CC

Here is a picture of our setup:

First, though probably not your issue, the CAN bus is not properly terminated. There should either be CAN leading away to the next device (most likely a PDP with the terminator set) or a 120 ohm resistor on the currently empty pins.

I think I've figured out everything up to the pressure regulator. It looks like the output of the regulator is split, with one going to the manifold, another going underneath. Where does that connect?

Trying to work out the black tubing connected to the manifold outputs. I cannot tell if the two inputs to the cylinder are coming from corresponding A/B ports, or adjacent sets of ports.
In any case it appears that you have plumbed the three unused A ports together, and the three unused B ports together. If all three (or four) of the solenoids are in the same position, this shouldn't be a leak, but if any of them is different from the others, you will be in an exhaust condition - pressurized air coming in one branch of the T and right out through another.
If the cylinder is plumbed to different solenoid valves, The only way you can operate it in this setup without dumping air is to switch all four ports at the same time.

The real solution to this problem (more manifold positions than you have separate items to control) is to plug the holes individually (we have some plugs in our shop, but don't know whence they came) or to use a "Blank Station Kit" like Vex's 217-2949 for each unused control. Edit: I see it is also called a blank station kit with the same part number on the WCP link you provided.

Edit2: Found the plugs like we have on MSC.

[bobbysq]

Originally Posted by GeeTwo

The real solution to this problem (more manifold positions than you have separate items to control) is to plug the holes individually (we have some plugs in our shop, but don't know whence they came) or to use a "Blank Station Kit" like Vex's 217-2949 for each unused control. Edit: I see it is also called a blank station kit with the same part number on the WCP link you provided.

Edit2: Found the plugs like we have on MSC.

You can also use smooth polycord of the same diameter as the tube. I don't know if this is any better/worse, but it's what we had on hand when we used pneumatics.

[DaveL]

Your set up is hard to follow. This is a problem for others trying to help, but more important its hard for you and your team to understand, troubleshoot and fix.

To make thinks easier for everyone, establish some color coding standards.
For example, you can use white tubing for the high pressure line. Then use green tubing for air that extends the piston and blue tubing to retract the piston.

That said there are way too many connectors and air lines.
Step 1. Simplify by only using 1 air tank.

Step 2. The regulator looks like it has 2 output pipes.
I have not seen this done. My suggestion is to cap the bottom opening.

Step 3. From what I can tell, air to push the piston is being sent from the 3rd valve (top) and air to retract the piston is being sent from the 2nd valve (bottom). You want to use one valve per cylinder.

To clean this up....
Remove all the tubes to the valves system except 1 providing air, 1 pushing the piston and 1 retracting the piston. All the other ports should be capped. Use a tee fitting and a loop of tubing to build the cap.

Flow limiting connectors can hide what is happening. I would replace these connectors with plain connectors. Once you understand how things work, try one before adding a second, as it might not be needed.

After you make these changes, take another picture but this time make sure all the tubes are visible, so we can help you trace their path.

Pneumatics is fun. Like programming, keep it simple to make it easy to understand.

Dave

[Mark McLeod]

I agree with the others about not connecting port-to-port on the manifold.
You need to deadend each unused port using, either a plug you can purchase, or juryrig a simple plug like the attached.

Other than that the tubing seems to be correct for your one cylinder.
The supplied pressure of 35psi is good to activate the solenoids.

Try swapping the two end hoses of the cylinder to see if the activated side is being affected by those flow controls.

Test using the manual blue button to make sure the plumbing is right, but then look back at the electrical connections.

1. Make sure the solenoid you expect (the second from the bottom or right in your photo) is wired to the correct PCM output. (The wires cross behind the regulator with another pair so they can't be traced from your photo)
2. Are both the light on the solenoid itself and the LED below the PCM solenoid connection changing when you attempt to switch cylinder direction?

The photo doesn't show the back of the regulator well, so look for the flow arrow on the regulator and make sure your high-pressure line is going in the port directly opposite the flow arrow (on the side of the tail end of the arrow).
The regulator has one input high-pressure port and three regulated low-pressure output ports and all can be used.
We use one of the output ports for the low-side pressure gauge and the other two low-side outputs can be used or plugged as desired to direct the low-pressure outputs.

[PVCMike]

Originally Posted by DaveL

Step 3. From what I can tell, air to push the piston is being sent from the 3rd valve (top) and air to retract the piston is being sent from the 2nd valve (bottom). You want to use one valve per cylinder.


Dave

These manifold blocks can be confusing to look at because the associated A and B ports are not right above each other, they're diagonal. I think they have it plumbed right (That part anyways)

All of the other points Dave made are great and I agree, clean it all up, remove the flow restriction fittings, plug the second regulator port, plug all the unused ports on the manifold.

You definitely cannot plumb A to B, I suspect that is why you're venting all your air. Plug those up or at the very least plumb all the excess A together, and all the B together.

You can make your own plugs for the push fittings in a pinch, super easy. Cut a 2" piece of tubing, heat one end with a heat gun (until it's very soft), then clamp it between some pliers. I would not recommend you use this method on the robot, but we do all the time in testing.

[FRC Team CC]

Here is a diagram I drew of our setup for the solenoids

It might not be a great drawing, but I hope it helps you understand our setup a little bit better

http://imgur.com/a/g2MT4

[dardeshna]

Originally Posted by FTC Team CC

Here is a diagram I drew of our setup for the solenoids

It might not be a great drawing, but I hope it helps you understand our setup a little bit better

http://imgur.com/a/g2MT4

Team 8 literally had this issue earlier today with the same manifold solenoid setup. While bridging A ports and B ports to plug them is probably also contributing to your issue, the way we resolved the original problem you described was actually quite simple.

Try unplugging all of the tubes from the manifold, unscrewing the solenoids, removing the rubber gaskets, and blowing out the internals of the solenoids and manifold with compressed air. Then reassemble carefully. And while you are at it, plug the unused ports properly with the loop setup someone posted a picture of above. For us, it was likely something was either loose or improperly installed.

You could think of this as the good old reboot! Good luck

Originally Posted by PVCMike

You can make your own plugs for the push fittings in a pinch, super easy. Cut a 2" piece of tubing, heat one end with a heat gun (until it's very soft), then clamp it between some pliers. I would not recommend you use this method on the robot, but we do all the time in testing.

Edit: ^^^ Haven't tried this myself but it does seem like a very good option for testing if you are out of connectors.

[DaveL]

Originally Posted by PVCMike

These manifold blocks can be confusing to look at because the associated A and B ports are not right above each other, they're diagonal. I think they have it plumbed right (That part anyways)

Thanks for the correction Mike.

One other point I'll make is that at each connector there is a chance of an air leak and each sharp bend causes internal air drag.

When you build the system for your competition bot, I would work out how to build the system with the fewest connections and the fewest bends.

For example: instead of having 2 air paths from storage, run air to tank1, then tank2 and then to the gauge. This eliminates, 2 tee connectors, 6 connections and 4 sharp bends.

Dave

[Daniel_LaFleur]

You can make your own plugs for the push fittings in a pinch, super easy. Cut a 2" piece of tubing, heat one end with a heat gun (until it's very soft), then clamp it between some pliers. I would not recommend you use this method on the robot, but we do all the time in testing.

Mike,

Just be aware that this method reduces the burst pressure of the tubing and can allow the tube to balloon and pop.