In a PLC, how does it execute a control scheme?

In a programmable logic controller (PLC), the execution of a control scheme primarily involves processing input signals and managing output devices according to the programmed logic. This process allows the PLC to operate in real-time, responding to various inputs from sensors, switches, or other devices in the system. The programmed logic dictates how inputs correlate to outputs, enabling the PLC to perform tasks such as turning motors on or off, activating alarms, or adjusting control valves based on the specific conditions detected by the inputs.

The capability to process input signals allows the PLC to make decisions and trigger outputs dynamically, based on current conditions rather than relying on pre-scheduled actions or fixed instructions. This adaptability is crucial for industrial automation, as it enables efficient and responsive control over complex processes in a wide range of applications. In essence, option B encapsulates the fundamental operation of a PLC, highlighting its role in input processing and output control guided by programmed logic.