Solenoids won't fire when compressor running

Out solenoids won’t fire when the compressor is running. Any ideas? We are stumped.

What are the other symptoms?

Do the PCM solenoid lights change?
Do the solenoid valve lights change?

Only while the compressor is running?
Work fine when the compressor is not running?

Have you tried running a basic program with just the solenoids defined?

In line answers attempted

Are these 12v or 24v solenoids?
What is the robot battery voltage reading while the compressor is running?

24 volt
Voltage is 10.8 while running

It sounds like the drop in battery voltage is stealing enough power from the solenoid outputs to prevent them from firing.

My first instinct was that the PCM voltage jumper was set on 12v, because the 12v output follows the battery voltage and dips when the battery dips-a good reason to use 24v solenoids.
The 24v setting for solenoids is a boosted voltage and maintains 24v even when the battery voltage drops.

I assume the PCM wiring is standard to the special port on the PDP with the 20a fuse?

Do the solenoids also fail to fire if you disable the compressor, but drop the voltage some other way, e.g., use a weak battery, or stall the robot drive against a wall?

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It appears the problem was the low battery and one bad solenoid. Strangely, we never had this problem before and we drain our batteries very low often during practice. Thank you for your help.

Draining batteries very low might not be a good idea. When practicing, we change the battery when it gets down to about 12.3 with the robot idle.

Thanks for the advice, we don’t have a battery plan and probably need one.

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