Which component directly influences the process variable in a control system?

In a control system, the actuator serves as the component that directly influences the process variable. Its primary function is to convert the control signals received from the controller into physical action within the system. For example, an actuator may be responsible for adjusting a valve position, changing the speed of a motor, or altering a flow rate, thus affecting the process variable being monitored and controlled.

The actuator plays a crucial role in implementing the control strategy determined by the controller. When the controller interprets data from the sensor (which measures the current state of the process variable), it determines the necessary adjustments to be made. The actuator then executes these adjustments, thereby directly affecting the process variable and ensuring that it remains within desired parameters.

Understanding this relationship is vital for anyone working in control systems, as it highlights how different components interact within the system to maintain stability and achieve desired outcomes.