Red Seal Instrumentation and Control Technician Practice Exam

What is the role of a sensor in a control system?

1. To convert signals into electrical energy

2. To regulate the flow of chemicals

3. To detect changes and provide data for control

4. To lock out malfunctioning devices

The correct answer is: To detect changes and provide data for control

In a control system, the role of a sensor is fundamentally to detect changes in the environment or the system itself and to provide relevant data that can be used for monitoring and control purposes. Sensors measure various physical properties like temperature, pressure, flow, and level, among others. This data is critical because it allows the control system to understand the current state of the process and make informed decisions, such as adjusting controls or activating alarms based on the detected conditions. By providing real-time data, sensors enable control systems to respond dynamically to changes, ensuring optimal operation and safety. While converting signals into electrical energy, regulating the flow of chemicals, and locking out malfunctioning devices are important functions in their own right, they do not encompass the primary purpose of a sensor in a control system. The essential function lies in the detection and data provision, which is the backbone of effective control and automation processes.