(New)matics advice

[ShIfTiNgBoT]

Otherwise either the solenoids will be fighting each other or the shaft will be free to slide around and change outputs at will.

I've never seen a double solenoid act like that. When unpowered entirely, it will use the air pressure from the inlet to prevent the valves from switching.

[Wren Hensgen]

Originally Posted by ShIfTiNgBoT

I've never seen a double solenoid act like that. When unpowered entirely, it will use the air pressure from the inlet to prevent the valves from switching.

Good answer. You don't need to keep one output powered to keep it in place. When you actuate it in one direction, the airflow is rerouted a little, and it actually serves to hold the spool (center shifty thingy) in place against vibration, shaking, or drops.

This means you can fire it with a pulse of power, and it will retain positions through power on and off, and even air supply on and off (There's grease on the spool which is sticky, and little indents that help hold the shifted spool in place).

The one thing I'd advise against doing is leaving both inputs fired. This may cause them to slide or move.