What is control loops?

Control loops are fundamental building blocks of automation and control systems. They are used to automatically regulate a process variable (like temperature, pressure, flow, or level) to a desired setpoint. A control loop typically consists of a sensor, a controller, and an actuator. The sensor measures the process variable, the controller compares the measured value to the setpoint and calculates a control signal, and the actuator manipulates a control element (like a valve or heater) to drive the process variable towards the setpoint. Common types of control loops include proportional (P), integral (I), derivative (D), PI, PD, and PID control.