What best describes process control?

• A. A one-time calibration of sensors to optimize energy use.
• B. A continuous monitoring and regulation of process variables by comparing to a setpoint.
• C. A method to design piping layouts for a plant.
• D. A technique for manual data logging only.

Answer: (B)

Process control is about continuously monitoring a process variable and using feedback to keep it at a desired value. In a closed-loop system, a sensor measures the variable and a controller compares it to a setpoint. The resulting error drives an actuator to adjust the process output, so the variable stays near the target even when disturbances occur. This ongoing regulation distinguishes true process control from static actions like a one-time calibration, which doesn’t continuously regulate; from designing piping layouts, which is about physical arrangement; or from manual data logging, which records information without automatic control.