Actuators in measurement and control In mechatronics and industrial control, an actuator is usually a device that:

Introduction / Context:
Sensing and actuation are complementary functions in automation. Sensors measure the physical world, while actuators impose change upon it. Correctly identifying actuator roles helps in system partitioning and component selection for robotics, HVAC, automotive, and process control.

Given Data / Assumptions:

• We are discussing typical actuator behavior (motors, valves, solenoids, heaters).
• System includes sensors, controllers, and actuators.
• Data conversion tasks are handled by ADCs/DACs and controllers, not actuators.

Concept / Approach:

An actuator accepts a command (often electrical) and produces a change in a physical variable such as position, flow, torque, or temperature. In contrast, a transducer like a sensor converts a physical variable into an electrical signal. Data processing/storage is the job of controllers or computers.

Step-by-Step Solution:

Verification / Alternative check:

Review standard block diagrams: Sensor → ADC → Controller → DAC/Driver → Actuator → Plant; the actuator is clearly the element applying force or change to the plant.

Why Other Options Are Wrong:

• Converts analog to digital: that is an ADC task.
• Stores/processes digital data: that is a controller/computer function.
• Converts physical to electrical: that is a sensor/transducer role.

Common Pitfalls:

• Labeling motor drivers or DACs themselves as actuators; they are part of the actuation chain but not the mechanical/physical output device.

Final Answer:

controls a physical variable.