PCM Solenoid Current Output

[ozrien]

Please read 1.2 Electrical Specifications in PCM User's guide. The total current is rated (sum of all channels).

Why do you need to know this?

[JohnFogarty]

I am attempting to use this http://www.mcmaster.com/#6425k11/=vusltm as part of our Pneumatic system. When wired to the robot the solenoid does not function. The solenoid uses a input of 24V & 0.15A. 3.5 Watts.

We are using 3 of them which if I'm not mistaken would mean a total current draw of 0.45A ~ 450mA

[ozrien]

That math seems right. What is the measured voltage across the solenoid signal? Is it 24V? Is the PCM solenoid channel's LEDs illuminated red?

If the current demand is close, you might need a supplemental PCM.

[JohnFogarty]

I found out the problem was on the connector of the solenoid. They use similar screw terminals to what is used on the power connector for the robo-RIO. A wire was not in the correct position in the connector.

All 3 of them are working now.

All is well. I'll keep in mind we might need another PCM if we use more solenoids. However I don't see that becoming a problem.

[ozrien]

I would still measure the solenoid voltage, or better yet just use the Self-Test while all the solenoid outputs are enabled and see if the 24V rail dips at all. Should be a quick test, just nav to the roboRIO webpage and press Self-Test after selecting the PCM. If the voltage rail doesn't dip as a result of turning them on then you should be good to go.

Self-Test button is explained here...
http://wpilib.screenstepslive.com/s/...ribution-panel

[Christopher149]

If the current draw was a problem, would it help to turn off the PCM output after actuating the solenoid (assuming it's a double solenoid and nothing will return on you when cutting voltage)?

[JohnFogarty]

Originally Posted by ozrien

I would still measure the solenoid voltage, or better yet just use the Self-Test while all the solenoid outputs are enabled and see if the 24V rail dips at all. Should be a quick test, just nav to the roboRIO webpage and press Self-Test after selecting the PCM. If the voltage rail doesn't dip as a result of turning them on then you should be good to go.

Self-Test button is explained here...
http://wpilib.screenstepslive.com/s/...ribution-panel

Will do the test first thing tomorrow.

Also we are using spring return single solenoid as shown in the link above.