Which sequence best describes a typical control loop operation?

• A. Randomly turning motors
• B. Directly powering actuators without sensing
• C. Storing data only
• D. Input from sensors, processing/deciding, output to actuator

Answer: (D)

A control loop operates by using feedback to adjust the system. It starts with sensing—the sensors measure the current state of the environment or the system. That sensed information is then processed by a controller or decision logic to determine what action is needed to reach the desired state. Finally, the determined action is sent to an actuator, which drives the system toward the target state. This sensing–processing–actuating cycle repeats continuously, forming a closed-loop control.

Why this sequence fits best: sensing provides real-time data about how things are, processing turns that data into a decision, and the actuator implements that decision to change the system. Other options skip essential parts of this loop—random motor action ignores feedback, powering actuators without sensing bypasses the decision step, and storing data alone doesn’t affect the system’s behavior.