PLC (Programmable Logic Controller)

A PLC is a ruggedised industrial computer that controls machinery and processes in real time, executing logic on inputs from sensors to drive outputs like valves and motors. PLCs are the workhorse of factory automation and the layer most plant data originates from.

PLCs replaced banks of relays with programmable, reliable control built for harsh plant environments. They run deterministic scan cycles, interface with sensors and actuators, and connect upward to SCADA and historians. Most condition-monitoring and analytics data ultimately starts as PLC or sensor signals, which is why PLC/SCADA integration is central to industrial AI projects.

Related terms

SCADA · DCS (Distributed Control System) · Industrial IoT (IIoT) · VFD (Variable Frequency Drive)

Software

Where this applies

Hot versus cold commissioning · State of Industrial Automation & Robotics 2026