Home > News > Content

About Optical Encoder

Apr 06, 2017

Optical Measurement Principles

A key component of optical rotary encoders is a code disk  mounted on the encoder shaft  . This disk is made of unbreakable plastic that has a concentric pattn of photoreceptors are illuminated or blocked from light by the pattern on the disk. For mern of transparent and opaque areas. Infrared light from an LED  shines through the code disk, onto an array of photoreceptors  . As the shaft turns, a unique combinatioultiturn models, there is an additional set of code discs arranged in a gear train  . As the main encoder shaft rotates, these discs are geared together to turn like the wheels of an odometer. The rotational position of each disc is monitored optically and the output is a count of the net number of rotations of the encoder shaft.


POSITAL's IXARC optical absolute rotary encoders use highly integrated Opto-aSICs, providing a resolution up to 16 bits (65,536 steps) per turn. For multiturn models, the measuring range is extended by the mechanically geared code disks to as many as 16,384 revolutions.

Advanatages of Optical  Encoders 

  • High resolution and accuracy along with excellent dynamic response

  • For use in areas with high magnetic fields

  • No risk of these devices losing track of their absolute position

  • No backup batteries required