In a PLC program, what is the term used to describe the continuous sequence of steps performed by the PLC processor?

The term that describes the continuous sequence of steps performed by the PLC processor is scanning. In a PLC, the scanning process involves the following steps: reading the inputs, executing the control program, and updating the outputs.

During scanning, the PLC continuously monitors the status of inputs to ensure it has the latest information about the process being controlled. After reading the input states, the PLC moves to the execution phase, where it processes the logic defined in the control program based on the current input states. This program execution determines the necessary actions, which then leads to updating the outputs to achieve the desired control strategy.

Scanning is crucial for real-time control since it allows the PLC to react to changes in the process environment and maintain proper control over the system. This cycle happens repeatedly, making it a foundational concept in PLC operation and programming. Other terms, while related to PLC functions, do not accurately define this integral process.