Which feedback device uses light to track the rotation of the ballscrew?

Which feedback device uses light to track the rotation of the ballscrew?

• A. Proximity Sensor
• B. Magnetic Sensor
• C. Tachometer
• D. Optical Encoder

Answer: (D)

Light-based position feedback uses a coded pattern that is read by sensors to determine rotation. An optical encoder does this by mounting a disk with transparent/opaque or reflective segments on the ballscrew shaft. A light source, such as an LED, shines on the disk as it rotates, and photodetectors read the pattern. As the pattern passes, the light is alternately blocked or reflected, creating pulses. Each pulse represents a small angular increment, so counting the pulses provides both rotation position and speed. This method is non-contact, so there’s minimal wear and high resolution, which is ideal for precise CNC feedback. Proximity sensors detect presence of nearby objects, magnetic sensors sense magnetic fields, and tachometers measure speed but do not provide the light-based encoded position information that an optical encoder does.

Light-based position feedback uses a coded pattern that is read by sensors to determine rotation. An optical encoder does this by mounting a disk with transparent/opaque or reflective segments on the ballscrew shaft. A light source, such as an LED, shines on the disk as it rotates, and photodetectors read the pattern. As the pattern passes, the light is alternately blocked or reflected, creating pulses. Each pulse represents a small angular increment, so counting the pulses provides both rotation position and speed. This method is non-contact, so there’s minimal wear and high resolution, which is ideal for precise CNC feedback. Proximity sensors detect presence of nearby objects, magnetic sensors sense magnetic fields, and tachometers measure speed but do not provide the light-based encoded position information that an optical encoder does.