ON-OFF-ON 3 way switch in CLICK

Hi,

Can I use a 3 way ON-OFF-ON switch with a Click PLC? how would it look like in a program? Obviously I would like all 3 positions to execute different things.
A simple application may be the switch up will turn of LED1, middle position will be OFF everything and switch downwards will turn of LED2, is this possible? or is a switch in a PLC merely either On or Off, that's it?

Thanks!!

An On-Off-On switch would just consume multiple inputs. At least two. One for either on position. Maybe three if you wanted to know the third "off" position.

Do not think of each input as a switch. Inputs are signals. An On-Off-On switch will have at least two signals.

Hello.
If you have a switch that has 3 positions On - Off - On then you will be closing a contact when:
You have the switch in the LEFT ON position....this will wire to one of your PLC inputs.
And also when you have the switch in the RIGHT ON Position......this will also wire to another PLC input.
When the switch is in the MIDDLE OFF Position no contacts will be closed so neither of your PLC inputs will be True (1).

The PLC does not care if there is a switch at all, you could twist the wires together and the PLC would not know if you just put the wires together or if you turned on a switch. It only cares if there is appropriate voltage at the input and if there is then that input will go and write a 1 in its bit box when scanned.

In Ladder Logic this would look something like this:

-[ ] -------------------------------( )
L.O.S.................................LED1

[IF L.O.S. THEN LED1]

-[ ] -------------------------------( )
R.O.S.................................LED2

[IF R.O.S. THEN LED2]

If switch is in the middle position then the Left On Switch (L.O.S.) Input and the Right On Switch (R.O.S.) inputs will not be true (1) so neither LED output will be True (1) (ON), they will both be False (0) (OFF).

And if you wanted you could even make the off position turn on a 3rd LED or whatever by doing something like this.

-[/]-------------[/]------------------( )
L.O.S...........R.O.S..................LED3

[IF NOT L.O.S AND NOT R.O.S. THEN LED3]

This way since there are no contacts on your switch closed and no voltage going to either of your PLC inputs from your switch then LED3 output will be TRUE (1).


This sounds a lot like a homework question but hopefully this will get you going in the right direction and encourage you to dig even deeper.
Keep at it and have fun with it.

BCS