Selecting the Appropriate Servo Position Feedback Device

This white paper discusses the selection of servo position feedback devices and their importance in closed-loop servo systems. It defines a position feedback device and explains its role in measuring the position of a motor's mechanical output. The document outlines various types of position feedback devices, including optical, inductive, and capacitive sensors, detailing their advantages and disadvantages based on factors such as cost, size, and performance. It emphasizes the necessity of these devices for applications requiring precise motion control, highlighting potential issues when motors operate without them. The paper further explains how position feedback is utilized in servo control loops, aiming to minimize error values between the commanded and actual positions. Additionally, it describes the significance of electronic commutation in brushless permanent magnet servo motors and the benefits of multi-turn absolute position feedback devices. Key specifications that define the performance of feedback devices, such as resolution, accuracy, and noise, are also discussed, providing a comprehensive understanding of their functionality.