Ladder logic diagrams are one of the most common ways to program a PLC (programmable logic controller), a device that controls industrial processes and machines. Ladder logic diagrams use symbols ...

Function block diagram is another graphical PLC programming language that uses ... applications in which you have a state machine or a sequence (an example is the traffic light control system).

When a PLC is used primarily to replace relays, timers, and counters, it's hard to beat the simplicity and usefulness of ladder diagram programming. Their ability to accept programming in ladder ...