When a PLC is used primarily to replace relays, timers, and counters, it's hard to beat the simplicity and usefulness of ladder diagram ... control either external PLC outputs or internal relay coils ...

THE use of function blocks for programming of programmable logic controllers (PLCs) is gaining wider acceptance. Rather than the classic “contact and coil” representation of ladder diagram or relay ...

Though PLC (programmable logic controller ... more than 90% of control programming is done in Ladder Diagram, said Yerger. “It's great for discrete logic systems that use a lot of Boolean algebra and ...