New user & a novice needs output help

[ricki]

Hi Folks!

I am acquainted with some electronic principles but not well versed and need help. I would like to connnect 6 solenoid valves and one stepper motor to the 888plc.  The solenoid valves are 24vac and are  each rated @6.9watts. I measured a coil resistance of 9.0 ohms. I have a 24vac step down transformer for the solenoid valves power supply and a separate 12vdc p/s for the plc & stepper motor operation.
Design help- simple switching output circuit that will drive the solenoids (AC) and protect the 12vdc driven plc output. Transistor types: BJT or FET?

Thanks,
Ricki

[support]

The simplest way is to use an electromechanical relay with 12V coil and 2A to 10A contact ratings. The PLC will drive the relay coil and the relay contact is used to conduct current for the 24VAC solenoid valve.

Solid state device are mostly DC operated, except TRIAC and SCR which are mostly used in 120VAC or 230VAC application. You can also buy some "solid state relay (SSR)" which are opto-coupler based TRIAC output. Check with the electrical suppliers for more details.

For stepper motor, you will need to get a stepper motor driver that works with your stepper motor. The T100MD888+ PLC will output pulses and direction signal to the stepper motor driver, but it would not directly driving the stepper motor at all.