I don't do massive amounts with PLCs, but thought I could quickly knock up some logic, but am struggling a little for the best way.
I want to use a single input which when turned on, turns on an output 1. When turned off, output 1 goes off. When the same input comes on again, it should turn on output 2 instead, when it goes off, output 2 would go off. I would usually achieve this without a PLC, using an impulse relay. What I need though is THREE outputs to operate one after the other.
This is for 3 pumps, so when called, each pump takes its turn. There is to be a timer which if exceeded brings the next pump on too, but that I can hopefully add, I just seem to be struggling with the best method of the sequential switching of the outputs.
I'm using an Alpha 2 as I have the programming lead and software, and have used them before for swimming pool pumps and fountain displays. Thought I could do this too, but can't quite grasp the best method. There is no counter I can see that you can "check" for it's value?
Any pointers would be great.