Mechanical rotary encoders, also called shaft encoders, are electro-mechanical devices that convert the angular motions (movement around fixed points) of rotary shafts into either analogue or digital signals.What are mechanical rotary encoders used for? Applications that require precision shaft rotation (movement around a specific point) make use of mechanical rotary encoders.These include industrial control machinery in factories, rotating radar platforms in satellite structures or computer input devices like trackballs and mice. Types of mechanical rotary encodersAbsolute encoders: have tracking functions to determine specific shaft positioning points in industrial equipment like CNC machines, lathes and bore machines. maintain positioning data even when power is cut from the system. When the system is switched on again it begins operating from the point where it stopped previously. Incremental (relative) encoders: record deviations in shaft position points over certain time frames. With each new time frame after power is cut and switched on again the encoder starts recording from a predetermined reference and measures the distance between the previous point and the current point.