The many similarities between the ladder diagrams used to program PLCs and the relay ladder logic When a PLC is used primarily to replace relays, timers, and counters, it's hard to beat the simplicity ...

A malfunction is nearly always on the input side or output side of the PLC. The ladder diagram shows you what the inputs and outputs are, and it shows how each output responds to a given input change.

You can use it to design simple to complex ladder diagrams. Timers, counters, comparators, memory bits, etc., are also easily accessible. After designing a PLC ladder logic diagram, you can run ...