What role do expansion modules play in a PLC system?

Expansion modules are integral components of a PLC (Programmable Logic Controller) system that play a crucial role in enhancing its capabilities. Specifically, they allow for increased input/output capacity. This means that when the base unit of a PLC reaches its limit for the number of devices it can connect to—such as sensors, switches, or actuators—expansion modules can be added to accommodate additional inputs and outputs, effectively scaling the system to meet the needs of more complex automation tasks.

The primary control unit of a PLC handles the processing and control logic, but it has a finite number of input and output connections. When the workload or the complexity of operations increases, the integration of expansion modules becomes necessary. This modular approach allows for more flexibility and customization within a PLC system, enabling it to adapt to the evolving requirements of industrial automation.

The other options do not accurately reflect the primary function of expansion modules. While programming efficiency and energy efficiency are important aspects of a PLC system as a whole, they are not directly associated with the function of expansion modules. Instead, the focus of expansion modules is predominantly on enhancing the system's capacity to interface with additional devices, thus increasing its overall functionality.