What are the three basic elements of a control loop?

What are the three basic elements of a control loop?

• A. Transmitter, Processor, and Valve
• B. Sensor, Controller, and Actuator
• C. Input, Processing, Output
• D. Sensor, Indicator, and Damper

Answer: (B)

The essential idea in a control loop is sensing the current condition, deciding what to do, and then making the system do it. The three basic elements are the sensor, the controller, and the actuator. The sensor measures the process variable (like room temperature) and feeds that information back. The controller compares that measurement to the desired setpoint and computes the necessary action, producing a control signal. The actuator takes that signal and changes the process accordingly, such as opening or closing a valve, adjusting a damper, or altering heating output. This creates a continuous feedback loop where sensing, decision-making, and action keep the system close to the target. Other components described in various systems, like transmitters, indicators, or specific valves or dampers, may appear in particular setups, but they aren’t the universal trio that defines a control loop.

The essential idea in a control loop is sensing the current condition, deciding what to do, and then making the system do it. The three basic elements are the sensor, the controller, and the actuator. The sensor measures the process variable (like room temperature) and feeds that information back. The controller compares that measurement to the desired setpoint and computes the necessary action, producing a control signal. The actuator takes that signal and changes the process accordingly, such as opening or closing a valve, adjusting a damper, or altering heating output. This creates a continuous feedback loop where sensing, decision-making, and action keep the system close to the target.

Other components described in various systems, like transmitters, indicators, or specific valves or dampers, may appear in particular setups, but they aren’t the universal trio that defines a control loop.