انکودر SICK مدل DFS60

An incremental encoder is a linear or rotary electromechanical device that has two output signals, A and B, which issue pulses when the device is moved.[1] Together, the A and B signals indicate both the occurrence of and direction of movement. Many incremental encoders have an additional output signal, typically designated index[2] or Z,[3] which indicates the encoder is located at a particular reference position. Also, some encoders provide a status output (typically designated alarm)[4] that indicates internal fault conditions such as a bearing failure or sensor malfunction.

Unlike an absolute encoder, an incremental encoder does not indicate absolute position;[note 1] it only reports changes in position[3] and, for each reported position change, the direction of movement. Consequently, to determine absolute position at any particular moment, it is necessary to send the encoder signals to an incremental encoder interface, which in turn will "track" and report the encoder's absolute position.