Programmable Logic Controller

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programmable controller | régulateur programmable | جهاز تحكم مبرمج | programmierbarer Regler | autómata programmable | controlador lógico programmable | ohjelmoitava ohjauslaite | controllore programmabile | プログラマブルコントローラ | sterownik programowalny | regulator programowalny | controlador programável | PLC | 可编程控制器


Standard Definition

National Definitions

United States


PLCs are computer-based solid-state devices that control industrial equipment and processes. While PLCs are control system components used throughout SCADA and DCS systems, they are often the primary components in smaller control system configurations used to provide operational control of discrete processes such as automobile assembly lines and power plant soot blower controls. PLCs are used extensively in almost all industrial processes [1]. PLCs are used in both SCADA and DCS systems as control components of an overall hierarchical system to provide local management of processes through feedback control. In the case of SCADA systems, they provide the same functionality of RTUs. When used in DCS, PLCs are implemented as local controllers with in a supervisory control scheme. PLCs are also implemented as the primary components in smaller control system configurations. PLCs have a user-programmable memory for storing instructions for the purpose of implementing specific functions such as I/O control, logic, timing, counting, three mode proportional-integral-derivative (PID) control, communication, arithmetic, and data and file processing [1].

Standard Definitions


Programmable controller is a microprocessor-based controller with a programmable memory for the internal storage of user-defined instructions. [2]

Régulateur programmable: régulateur à base de microprocesseurs comportant une mémoire programmable pour la mémorisation interne d'instructions définies par l'utilisateur [2]

See also



  • ERNCIP's Thematic Group on Case Studies for the Cyber-Security of Industrial Automation and Control Systems [1]