The main function of optical encoders is to detect position change by counting scale lines with a special detector that works together with a LED light source. Then it transforms these pulses into electrical signals for further data processing. Main parts of such sensing units are the following: light source (mostly LED), sensor, movable mask or phased array. So there are two main types of such devices – mask type and phased array.
Mask type encoders are the most frequently used position feedback device as it is simple and affordable. The encoder wheel has a series of notches on it, and there is a fixed sample cliché. As the wheel rotates different notches are covered. These patterns are fixed with a sensor and relative information subsequently transferred to a main data collection unit. There are also optical mask type encoders with two sensors so you are able to collect more information, for instance speed.
A more solid model of Dynapar optical encoders is phased-array units. These apps generate multiple signals simultaneously that subsequently are consolidated into a single average signal. Such types of encoders are used in hard environments with unstable conditions such as vibrations and shocks. Another advantage of phased-array design is that you require less precision during equipment setup.