Which component in a closed-loop system converts a control signal into mechanical movement to adjust the process?

Which component in a closed-loop system converts a control signal into mechanical movement to adjust the process?

• A. Sensor/Transmitter
• B. Actuator/Valve
• C. Power supply
• D. Controller

Answer: (B)

In closed-loop control, the component that converts a control signal into mechanical movement is the actuator. After the controller processes the sensor feedback and determines the necessary correction, the actuator receives that electrical or pneumatic signal and translates it into physical motion—such as opening a valve, moving a valve stem, or driving a motor—to adjust the process variable. The sensor/transmitter only provides real-time measurements of the process, feeding the loop. The power supply simply provides energy to the system, not the actual conversion. The controller generates the control signal but does not directly enact the change; that role belongs to the actuator, which can take forms like electric motors, hydraulic cylinders, pneumatic pistons, or control valves depending on the application.

In closed-loop control, the component that converts a control signal into mechanical movement is the actuator. After the controller processes the sensor feedback and determines the necessary correction, the actuator receives that electrical or pneumatic signal and translates it into physical motion—such as opening a valve, moving a valve stem, or driving a motor—to adjust the process variable. The sensor/transmitter only provides real-time measurements of the process, feeding the loop. The power supply simply provides energy to the system, not the actual conversion. The controller generates the control signal but does not directly enact the change; that role belongs to the actuator, which can take forms like electric motors, hydraulic cylinders, pneumatic pistons, or control valves depending on the application.