A PLC Processor Module is the core computational component within a Programmable Logic Controller (PLC) system. It is responsible for executing the user-programmed control logic (ladder logic, function block diagrams, structured text, etc.), processing input signals from sensors and devices, performing calculations and data handling, and generating output signals to control actuators, motors, valves, and other industrial equipment. It manages the scan cycle, communication with other modules (I/O, communication, special function), and system diagnostics. The module typically includes a microprocessor, memory for the operating system and user program, and communication interfaces. It operates on a cyclic scan principle: reading input states, executing the program, updating outputs, and performing housekeeping tasks. Key parameters include processing speed (0.01–0.1 ms/step), program memory (64–512 KB), data memory (32–256 KB), digital I/O points (16–1024), analog I/O channels (4–64), supply voltage (24 V DC ±10%), power consumption (5–20 W), operating temperature (-40 to 85 °C), storage temperature (-40 to 85 °C), relative humidity (5–95% non-condensing), ingress protection (IP20–IP65), communication ports (1–4), dimensions (100–200 x 100–150 x 50–100 mm), and weight (0.5–2.0 kg). These values are reference ranges; verify the actual model's specifications with the manufacturer. The module is typically housed in a plastic/composite enclosure with a printed circuit board and electronic components. It is designed for industrial environments and may comply with standards such as IEC 61131-3 for programming languages, IEC 61131-2 for supply voltage, and IEC 60068-2-1/2 for temperature testing, and IEC 60529 for ingress protection. Always confirm compliance with the supplier.
The processor module operates on a cyclic scan principle. Each scan cycle consists of: 1) Reading the status of all input modules and storing the data in an input image table. 2) Executing the user program logic sequentially, using the input image data and internal memory to solve the control logic and update an output image table. 3) Writing the output image table states to the physical output modules. 4) Performing housekeeping tasks like communication, self-diagnostics, and updating system status. It contains a microprocessor, memory (for operating system, user program, and data), and communication interfaces.
