An emitter on one side of the disc emits light through the slots to a receiver on the other. A 1000 PPR encoder has 1000 slots cut into the disc. The number of slots in the disc varies depending on the resolution of the encoder. Optical encoders contain a disc within the case with “slots” or “lines” cut into it. Optical EncodersĪll of the Koyo encoders sold by AutomationDirect are optical rotary encoders. All the encoders sold by AutomationDirect are rotary encoders. A 2000 PPR encoder has twice the resolution of a 1000 PPR encoder. Rotary encoder resolution is measured in pulses per revolution (PPR), also known as “line count”. The scale (coded strip) has a set resolution embedded into it or on it that the head reads. A linear encoder’s resolution is measured in pulses per distance (pulses per inch, pulses per mm, etc.). Rotary and linear encoders both define their accuracies in similar ways. A linear encoder is very similar to a tape measure, while a rotary encoder is more like a measuring wheel. A rotary encoder typically consists of an internal coded disc and a sensing head to determine rotary position. A linear encoder typically consists of a scale (a coded strip) and a sensing “head” that reads the spacing between the scales’ coding to determine position. There are two basic geometries for encoders: linear and rotary. The position information can be read in many ways (optically, magnetically, capacitively, etc.).

An encoder (for industrial controls) is a special sensor that captures position information and relays that data to other devices.

Encoder totem pole output