A PLC (Programmable Logic Controller) is a rugged industrial computer tailored to monitor inputs, perform logical processing, and control outputs in real time. It is designed to withstand vibration, temperature variations and electrical noise, with a fast scan loop that ensures machines respond on time.
PLCs revolutionized automation in the 1960s as a replacement for relay-based hardwired logic - offering programmable flexibility, easier reconfiguration and high operational reliability. Modern models support multiple programming languages according to the IEC 61131-3 standard, such as ladder logic, function block diagrams and structured text.
In practice, PLCs are used in many applications - from small standalone units to large rack systems with thousands of I/O channels. They are found across automotive manufacturing, food production, infrastructure systems and building automation, and often include network connectivity for communication with SCADA, HMI or other PLCs.
