The absolute type encoder

The biggest drawback of the incremental encoder is power system (such as temporary power outage) it cannot track any changes by incremental encoder output.

Therefore, in order to provide accurate position data, the incremental encoder must return to the initial position at startup. For conveyor shut down every night, every morning, then restart the application, the incremental encoder to return to the initial position will not affect the application. But in automotive applications, such as the assembly of mechanical arm if welding power as the seat stent, incremental encoder to return to the initial position will be seriously damaged products and mechanical arm. Absolute encoder are ideal for high reliability.

Unlike incremental encoder, absolute encoder will not output pulse, but output digital signals to indicate the encoder position, and the encoder position as a static reference point in the absolute coordinate system. Therefore, when power is absolute type encoder can still keep its absolute position record. After the restart the system can immediately restore movement, do not need to return to the initial position.

Absolute rotary encoder has a connection on the shaft encoder and a fixed grating, the every trip point allows the system to generate a unique binary identifier (linear sensor principle of work similarly, for the sake of simplicity, this article focuses on the rotary encoder). As code rotating to the fixed grating, the system will read regularly identifier, as several digital signal output. Relevant controller or inverter can poll the encoder to capture the location data, and can be directly used to the data or the processing for the speed of information.