Grounding Solenoids / Spikes

[7-11number1]

As of tonight our robot is up and running. We are launching with pneumatics but between the 12V wire, PWM cables (for the relays) and pneumatic tubing is it starting to look like spagehtti.

To clean some of this up, I was wondering can the pneumatic solenoids can share a common ground?

[RyanN]

Yes, this is perfectly acceptable.

[Al Skierkiewicz]

7-11,
Under certain conditions the answer is yes. Those conditions are that the power supply returns go back to the common point on the breaker panel or to a common point on the Rockwell block. If you tie several returns together to a common wire (sized appropriately) and that then goes back to one of the common points, that is acceptable as long as it is insulated.
I don't always know what someone has in mind when they ask a question like this. You may not tie the common point to the robot frame/chassis as is common practice for auto electricals.