PLC Program Scan Cycle: Phases, Timing & Optimization
In every automated process, timing is everything. Whether it’s a conveyor belt, a motor, or a sensor, delays or malfunctions often trace back to a system's internal cycle. One crucial element in modern automation is the PLC program scan cycle , which controls how fast inputs are read, logic is executed, and outputs are updated. Understanding how a PLC works—and how its scan cycle affects real-time response—is key to maintaining stable and efficient operations. What Is the PLC Program Scan Cycle? The PLC program scan cycle is the continuous process a PLC follows to execute control logic. It consists of reading all inputs, executing the programmed instructions, updating the outputs, and handling communication and diagnostics. This cycle runs repeatedly while the PLC is in RUN mode. Why Understanding the Scan Cycle Matters The scan cycle directly affects the real-time behavior of a control system. A slow or inconsistent scan time can cause delays in machine responses, missed senso...