Encoders

Encoders are devices or circuits that convert information from one format or code to another. In engineering and manufacturing, encoders provide feedback about the position, direction, or speed of a moving element, typically a shaft or linear slide. They are widely used in robotics, CNC machines, elevators, and motor-control systems to enable precise control and monitoring.

Rotary encoders come in incremental and absolute varieties. Incremental encoders generate a stream of pulses as the output rotates; two output channels in quadrature allow direction detection and, with an index pulse, reference position. Absolute encoders encode the position on a code track and provide a unique digital value for each angle or position, even after power loss. Linear encoders measure position along a line. Common sensing methods include optical (code wheel with a light source and detector), magnetic (magnetized scale with Hall or magnetoresistive sensors), and capacitive or inductive approaches. Resolution and accuracy depend on the code pattern, sensor quality, and signal processing.

Output formats vary: incremental encoders produce pulses or quadrature signals, sometimes with an index; absolute encoders output binary or gray code words corresponding to position, with multi-turn variants tracking multiple revolutions. Applications include motor control, robotics, CNC machinery, actuation feedback, and precision positioning systems.

Beyond motion sensing, encoders also refer to devices or algorithms that convert data from one representation to another for transmission or storage. Data encoders compress or format information, such as audio/video encoders, text encoders, or error-correcting codes. They may be lossless or lossy and are chosen based on bandwidth, latency, and quality requirements, with interfaces ranging from serial buses to parallel signaling.