Programmable Logic Controller (PLC).

A ruggedized industrial computer that executes deterministic control logic to read sensors and drive actuators in real-time processes. It belongs to the OT / ICS / IoT category of cybersecurity.

A ruggedized industrial computer that executes deterministic control logic to read sensors and drive actuators in real-time processes.

A Programmable Logic Controller (PLC) is a hardened industrial computer running cyclically scanned control logic (ladder, function block, structured text) to control physical processes. PLCs read digital and analog inputs from sensors, execute control algorithms, and drive outputs to motors, valves, and other actuators with strict timing guarantees. They are programmed through engineering software (Siemens TIA Portal, Rockwell Studio 5000, Schneider EcoStruxure) and communicate via Modbus, PROFINET, EtherNet/IP, or OPC UA. Because PLCs typically lack authentication on their engineering interfaces, attackers who reach them can upload malicious logic, force I/O, or alter setpoints — a technique used in Stuxnet and demonstrated in many later ICS attacks.

Defences for Programmable Logic Controller (PLC) typically combine technical controls and operational practices, as detailed in the full definition above.

Common alternative names include: PLC, Industrial controller.