We are using 24V solenoids, wired into the PCM. The PCM is set to 24V, the lights on the solenoid ports (small red ones on PCM) are lighting up, and the solenoids fire manually. There is voltage going to the solenoids (we tested with a voltmeter), but the solenoids aren’t actuating.
The PCM is blinking orange when disabled, blinking green when enabled, and blinking red when triggering the solenoids. The red blinks are constant and according to the manual this means a compressor issue. We tried flipping the positive and negative on the compressor but that didn’t change anything, the compressor is still filling air because it fires manually, so I can’t see the problem. There are also no visual indications that the compressor isn’t working.
Thank you for any help you may be able to provide. My team and I would really appreciate it.
I am no expert, but I believe the solenoids are not polarized. The coil is active when there is current and passive (pilot air holds last state) when no current. They even work with AC signals.
My suspicion (as raised by another post) is that the code is sending an activate signal and immediately sending a deactivate which is too fast for the mechanical solenoid to move, causing the dim light and the 200mV measured voltage. I would like to see if they can send a healthier pulse.
I’ve had solenoids that were directional.
The LED generally turns on, but the coil does not trip when wired backwards.
If they are pulsing too quickly, then that will show up on the PCM indicator per solenoid.
For a double solenoid, if the PCM light is on then the solenoid will be driven to the corresponding position. If the light is off, then the position is indeterminate. If both sides of the solenoid are tripped at the same time then it’s also not going to move.
For a single solenoid, the PCM light has to be on for the solenoid to move away from the home position. When the PCM light is off a single solenoid will return to the home position.
We tried working backwards on our other identical robot. We tested the voltage going to the solenoids forwards and reverse and it actuated with 24v. With only 12v the solenoids light up, but don’t actuate. The pulse in code is 0.25 seconds and works perfectly fine on this robot (the code is identical for both).
On our competition bot (the one that doesn’t work) we are going to oscope and multimeter the signal from the PCM to solenoid and if it is correct (24v and 0.25sec pulse) we will swap out the solenoid and if it is not correct we will swap out the PCM.