What distinguishes open-loop control from closed-loop control?

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Multiple Choice

What distinguishes open-loop control from closed-loop control?

The key idea is feedback. In open-loop control, the system sends a command to the actuator based on the input alone and does not check what the output actually is. If something in the process changes—like a load variation or a disturbance—the system won’t automatically correct itself because there’s no feedback to guide adjustments. In closed-loop control, sensors measure the actual output, compare it to the desired setpoint, and use that feedback to adjust the actuator so the output moves toward the setpoint. This ongoing comparison and adjustment keeps the process on target even in the face of disturbances. Think of it this way: a toaster with a fixed timer operates open-loop—no measurement of the toast level, just a set duration. A room thermostat controlling heat is closed-loop—it measures the room temperature and ramps heating up or down to maintain the setpoint. That’s why closed-loop uses feedback to steer toward the setpoint, while open-loop does not.

The key idea is feedback. In open-loop control, the system sends a command to the actuator based on the input alone and does not check what the output actually is. If something in the process changes—like a load variation or a disturbance—the system won’t automatically correct itself because there’s no feedback to guide adjustments. In closed-loop control, sensors measure the actual output, compare it to the desired setpoint, and use that feedback to adjust the actuator so the output moves toward the setpoint. This ongoing comparison and adjustment keeps the process on target even in the face of disturbances.

Think of it this way: a toaster with a fixed timer operates open-loop—no measurement of the toast level, just a set duration. A room thermostat controlling heat is closed-loop—it measures the room temperature and ramps heating up or down to maintain the setpoint. That’s why closed-loop uses feedback to steer toward the setpoint, while open-loop does not.

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