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 ...

Ladder logic uses switch or relay contacts to implement Boolean expressions. In years past, ladder logic was made possible with discrete relays and was sometimes termed “relay logic.” Today most ...

When learning ladder logic, I was told that some new PLC systems were moving to scripted programming languages. My instructor assured us that we would not need to know anything other than ladder logic ...

Old habits die hard. But change is inevitable. And in this case, if proponents are right, change is on the way in the form of an open PLC programming standard known as IEC 61131-3. Promulgated by the ...