connecting PNP sensors into PLC inputs

[engsatapex]

Hi guys,

I would like to know how to connect PNP sensors in parallel into one PLC input. Does anybody know how to do this? Many thanks in advance.

While I am asking the questions, how do you connect PNP sensors in series into one PLC input?

 

[fangas]

My first thought, why?

Normally you don't. A parallel connection will give you a confusing OR circuit. And a series connection will give you an equally confusing AND circuit. at least it will be confusing to the person that comes along behind you and tries to figure out if there's a logical problem, or a hardware/switch problem.

But, if you must, for parallel, just run all the switch outputs to the input together.

For series, run the output of 1 switch to the + of the next and continue. All the -'s will go together. Beware of voltage drops from one switch to the next.

At least I think it works that way. Never done it or, considered it.

It's a heckuva a lot easier to put in a larger input card & do all the OR and AND logic programatically though. And I can't figure why anyone would do it this way

Ed