Re: Proper way to connect a solenoid
 

Do you guys know of a way to use a non spike relay on the bot? We only have two working ones and one is on the compressor, we want to have 4 cannons and our team is short on cash so we really don't want to spend the $35 for each new spike

Re: Proper way to connect a solenoid
 

I won't be able to post a picture today because I don't have access to the robot right now. It's at another members house,I'll ask him to post one later today

Re: Proper way to connect a solenoid
 

In terms of code, I am using Java commandbase. I have "public static Relay cannon = new Relay(4);" in RobotMap. I also have a command setup to fire. In the initialize i'm doing "RobotMap.cannon.set(Relay.Value.kOn);" where cannon is the name of the Relay and RobotMap is the place where it is defined. I can verify that the command is running because I have a debug statement which is printing when I push the button to run it.

Re: Proper way to connect a solenoid
 

Using kOn is turning both sides of the relay on, which won't cause the solenoid to fire. You want to use kForward which sets the + side to 12v and the - side to ground.

Alternately, you can set the direction to forward in the constructor and then use kOn.

Re: Proper way to connect a solenoid
 

I'm reading that spikes can only switch 12v, which is why I believe that it didn't work for us.

You mentioned earlier, and I'm reading here http://team358.org/files/pneumatic/ that 24v solenoids can be run through the cRIO power. Are you familiar with how this is done?

Re: Proper way to connect a solenoid
 

Sorry, I forgot to mention that after kForward didn't work I switched it to kOn. Thank you though, I will change it back now

Re: Proper way to connect a solenoid
 

oOPS Double post.

Re: Proper way to connect a solenoid
 

[quote=tr6scott;1286265]But you said the valve worked by direct connecting to the battery, so it should work with the spike connected to 12v power.

I understand you don't want to use the spikes due to the cost, and if you need 4 of them. Why I suggested them, is they are very robust, and fused, which is nice when you are putting stuff together outside of specifications.

This diagram, http://team358.org/files/programming...ionDiagram.pdf shows two solenoid cards, one is powered by 24vdc and one is powered by 12vdc.

As you already stated that 12vdc worked, I would suggest that you wire to 12v to test, this is because we are working outside of specs, and if something goes, you may blow the 24vdc power supply in the power distribution board, and the cost money too.

Here is the manual to the solenoid breakout, http://www.usfirst.org/sites/default...20Breakout.pdf You will need a 2 pin pwm cabel, wired to the solenoid + to + ground to ground. When you turn on the output in the program the solenoid will fire with the voltage that you apply to power input terminals.

Re: Proper way to connect a solenoid
 

The 24 volt AC sprinkler valves that we used would not work on 12 VDC with pressure. They need about 18 volts to fire. You may have a similar issue.

You should connect them to the pneumatic breakout with that module being powered with 24 VDC as shown in the diagram Scott linked to in the thread above this.

We have done this for several years and it works fine.

Attached is an updated version of the same drawing. It shows how to get power for a 24 volt solenoid and this is even legal. Your circuit is fully protected.

I would suggest installing diodes across the coil to absorb the back EMF from the coil. Here is a link that explains. You can leave out the resistor.

http://en.wikipedia.org/wiki/Flyback_diode

You should see the green lights on the module change when you trigger the valve. Remember, you need a short pulse, about 0.5 second is good, so your code will need to make that pulse with a small state machine or you could just connect it to a button on the joystick and let the operator create the short pulse.

Have fun!

-Hugh

Re: Proper way to connect a solenoid
 

One thing that you can do to get the 24 V that you need is share the power with the cRio. This is something that teams have done in the past I believe. The port off the PD board that you wire to power the cRio, there are 4 wire holes there, you can draw and extra wire from it to power the solenoid breakout panel.

There are probably some concerns with this. I would not recommend using this method and mixing 12V and 24V solenoids. Some people would not use this method at all.