pneumatic valve control

[mechanicer]

I am planning to control pneumatic solenoid valves in my fixture which hold the workpieces with PC.
Operator opens and closes solenoids manually. If i can construct the system using role, pneumatics will be opened and closed automatically by CNCPRO while gcode is running.

Are there anybody controlling pneumatic solenoid valves with PC?

[Al_The_Man]

Use an unassigned M code and a spare output, and switch using a buffer 2n7000 or equiv. for 24vdc sol.
If 110vac solenoid use an opto switch.
Al.

[ger21]

Al, can you use an SSR to turn on a 110V solenoid?

[Al_The_Man]

Gerry, Yes, Triac output type SSR.
Al.

[gar]

060123-2110 EST USA

ger21:

You can use a Triac or SCR solid state relay on any load within its ratings provided that to turn off the Triac or SCR you must remove the trigger and drop the load current below the device's holding current. Dropping holding current to zero is automatic on a normal AC circuit.

If you used a Triac or SCR on on a DC load it would stay on forever if you did not drop the load current to near zero. A capacitor and another SCR that is turned on is one way to turn off the first Triac or SCR in a DC circuit. A mechanical relay is another.

If your SSR uses a MOSFET, then it will turn off a DC load without the current going to zero.

Any time you turn off the current to an inductive load when the current is not near zero will require some sort of snubbing circuit to prevent excessive induced voltages.

.