PLC 5 Puzzle

[Newbie Tony 0]

Hey you programming wizards. I have 4 digital inputs. I want to activate an Output whenever any 1 to 3 of them are ON. Can you think of any elegant solution, e.g. 1 rung, that would do this? Thanks for looking!

[b_carlton 61]

Think this way "At least one of the four is on AND at least one of the four is off". I'll post a rung if you need further help.

[chelton 66]

Or output is "ON" as long as inputs are not all "ON or all"OFF"

[b_carlton 61]

That should work, though this was my vision of the rung ...

[JeffKiper 9]

Bernie you make it look to easy

[b_carlton 61]

Except that the bottom branch of the first group should have been I:0/3 (not I:0/2).

[Newbie Tony 0]

thanks for the help folks!