What role does a sensor play in a control system?

In a control system, a sensor plays a critical role by measuring a process variable—such as temperature, pressure, flow, or level—and providing this information as feedback to the controller. This feedback is essential for the controller to make informed decisions about how to adjust system outputs in order to maintain the desired setpoint or operating conditions.

The function of the sensor is foundational to the control loop; it provides real-time data that allows the control system to respond dynamically to changes in the process. Without accurate measurement and feedback from the sensors, the controller would lack the necessary information to effectively manage and regulate the process.

Sensors are not directly responsible for executing commands—that function is typically performed by actuators or other components in the control system. While maintaining system security and signaling alarms are important aspects of a control system, those tasks are usually managed by other system components and are not the primary responsibility of the sensor. Thus, the sensor's main purpose is to measure the process variable and relay that information back to the controller to facilitate effective control actions.