Automation Glossary

PLC, RTU, HMI & DCS Glossary

Merobix Engineering • • 4 min read

Controllers and operator interfaces: PLCs, RTUs, HMIs, DCS, I/O, and scan cycles. 162 terms in this topic - each defined in plain English on its own page.

All Glossary Topics

Controllers execute the logic and operator interfaces display it. This topic collects the vocabulary of both: PLC and RTU hardware and programming concepts (scan cycles, ladder logic, timers, latches, I/O modules), the IEC 61131-3 languages, and the HMI design ideas (faceplates, high-performance displays, situational awareness) that determine whether an operator catches a problem or misses it. Programming-language terms sit alongside display terms deliberately - in practice one engineer usually owns both ends of the loop.

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