What function do input modules serve within a PLC?

Input modules within a PLC (Programmable Logic Controller) serve the critical function of converting various types of electrical signals from input devices, like sensors and switches, into a format that can be processed by the PLC's CPU. These input devices might generate analog signals (such as temperature readings), digital signals (like push button presses), or other forms of data related to the physical state of a machine or process.

When an input module receives a signal, it translates that signal into a binary format (0s and 1s) that the PLC can understand and utilize for decision-making processes. This conversion is essential because the PLC operates on digital information, and the input module serves as the intermediary that bridges the gap between the real-world conditions sensed by equipment and the programmable logic implemented in the PLC.

In this capacity, input modules play a foundational role in the entire automation system, as they supply real-time data that the PLC uses to execute control logic, affecting the outputs and overall system behavior. This functional clarity underlines why converting electrical signals into usable data is pivotal within the PLC architecture.