PLC, BCD control

[patrickbyron044@gmail.com]

Good Day everyone,

I have a project to do, and i am wishing someone has done something like this before.

Using a PLC as i controller.
2 x D/I inputs need to be coded to represent Forward, Off, Reverse. Using a DPDT toggle switch.
2 x D/I inputs need to be coded to represent Low range, Off, High range. Using a DPDT toggle switch.
Another group of D/I inputs selecting different operating modes, 0) No selection, 1) 1st gear 2) 2nd gear etc. to 6) 6th gear. Using a BCD rotary switch.
7 x D/O Outputs will be driving 7 x 24V relays representing solenoid valves. in a specific truth table sequence.

I have dabbeled with a Allen-Bradley Micro800 and BARTH using Ladder, and I still dont know where to start

[Benta]

For the first two switches, do you mean DPDT momentary switches with a neutral position? EG, press down = reverse, press up = forward, release switch = off?

[patrickbyron044@gmail.com]

Thank you for your response.

Yep the two toggle switches are the normal chassis mount, centre off, up on, centre off, down on. non latching.

[Benta]

Well, the first two are easy. I don't understand why you'd need DP there.
SP of the type momentary-off-momentary would suffice.

[patrickbyron044@gmail.com]

You are correct, the second pole is for pilot lights on the panel to indicate modes selected. High range-Low range, Forward-Reverse.
I am going to attach diag. shortly.

[Benta]

You are correct, the second pole is for pilot lights on the panel to indicate modes selected. High range-Low range, Forward-Reverse.

That's not good design practice. The good way is to let the PLC control the lamps. Then you have a feedback that the PLC has actually read the switch correctly.