Which component of a PLC is responsible for executing the ladder logic program?

The processor is the central component of a Programmable Logic Controller (PLC) that is responsible for executing the ladder logic program. It interprets the instructions written in ladder logic, which is a graphical programming language used to develop control programs for industrial automation. The processor continuously scans the input signals, executes the logic based on the defined program, and then updates the output states accordingly.

In a typical operation cycle, the processor first reads the status of all input devices via the input module, processes the ladder logic program according to those inputs, and finally sends commands to the output devices through the output module. This cycle occurs rapidly, allowing the PLC to respond effectively to changing conditions in real-time.

The other components, such as the input module, output module, and power supply, play supporting roles. The input module gathers information from sensors and switches, while the output module controls actuators or other devices in response to the processor's decisions. The power supply provides the necessary electrical power to all components of the PLC system, but none of these will execute the program, thus underscoring the critical function of the processor in the PLC architecture.