Question:
What is a final control element in a control loop?
Options:
A) Sensor
B) Control valve
C) Transmitter
D) Element
View Answer
Correct Answer: B) Control valve
Detailed Explanation
A final control element (FCE) is the device that physically acts on the process to change the manipulated variable.
The most common example is a:
Control valve
It receives the controller output signal (e.g., 4–20 mA) and adjusts flow, pressure, level, or temperature accordingly.
Control Loop Structure
Sensor → Transmitter → Controller → Final Control Element → Process → PV
The final control element executes the controller’s command.
Why Other Options Are Incorrect
A) Sensor → Measures the process variable.
C) Transmitter → Converts sensor signal into standard signal.
D) Element → Too generic; not specific.
Other Examples of Final Control Elements
- Control valve
- Variable Frequency Drive (VFD)
- Damper actuator
- Heater element
- Motor starter