Which statement about decision making in a control loop is true?

• A. Control loops never make decisions.
• B. Decision making is typically involved in control loops.
• C. Decision making is optional in all control loops.
• D. Decision making happens after execution.

Answer: (B)

Decision making is central to most control loops. In a closed-loop system, sensor data are used to form an error between the desired setpoint and the actual process variable, and the controller decides what action to take based on that error using the chosen control law (like PID, model predictive control, or state feedback). That decision then drives the actuator to adjust the process, and the new state is measured again to continue the cycle. So the loop’s purpose is to select the appropriate control action to drive the process toward the target.

Saying there is never any decision is incorrect because even simple on/off or threshold-based rules require a decision to switch states. Claiming decision making is optional in all loops isn’t accurate since most loops rely on selecting an action to influence the system. And saying decision making happens after execution misrepresents the flow—the action is determined first, then executed, with the result feeding the next decision.