Which statement best describes the purpose of a discrete input module in a PLC system?

The purpose of a discrete input module in a PLC (Programmable Logic Controller) system is to read the status of discrete inputs from various field devices such as switches, sensors, and buttons. These inputs are typically in binary form, representing either a high (on) or low (off) state. When a discrete input is activated, the module registers this change and sends the corresponding signal to the PLC’s processor for further processing. This is essential for the PLC to respond accurately to user commands and environmental conditions, allowing it to make decisions based on real-time data.

The discrete input module acts as an interface between the physical world and the PLC, interpreting the signals from field devices so that the controller can manage outputs and automate processes effectively. This functionality is a foundational element in automated control systems, making it possible for the PLC to implement logic based on the state of various input devices.