Which component in a servo system typically provides the feedback signal used by the drive for closed-loop control?

Which component in a servo system typically provides the feedback signal used by the drive for closed-loop control?

• A. Proximity sensor
• B. Thermocouple
• C. Encoder
• D. Pressure sensor

Answer: (C)

In a servo system, the drive relies on feedback to know the actual motion and compare it to the command. An encoder is the component that provides this feedback signal, converting shaft position (and often speed) into electrical pulses the drive can count and interpret. With high-resolution position data from the encoder, the control loop can continuously correct motor output to reach the desired position or speed. Proximity sensors detect presence or distance to a target but don’t give precise, continuous position information needed for tight closed-loop control. Thermocouples measure temperature, and pressure sensors measure fluid or gas pressure—neither provides the angular or rotational feedback needed for precise motor control.

In a servo system, the drive relies on feedback to know the actual motion and compare it to the command. An encoder is the component that provides this feedback signal, converting shaft position (and often speed) into electrical pulses the drive can count and interpret. With high-resolution position data from the encoder, the control loop can continuously correct motor output to reach the desired position or speed.

Proximity sensors detect presence or distance to a target but don’t give precise, continuous position information needed for tight closed-loop control. Thermocouples measure temperature, and pressure sensors measure fluid or gas pressure—neither provides the angular or rotational feedback needed for precise motor control.