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 ...

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 ...

The PLCopen Motion Control Specification harmonizes the access of motion-control functionality across platforms, explains Eelco van der Wal, managing director of PLCopen (www.plcopen.org), Zaltbommel, ...