Absolute coder using coding disc - has two detectors as unit, set at preset spacing along sign pattern track on-disc

摘要

A coding disc has a first track with an absolute sign pattern, along which detectors are fitted for a relative motion w.r.t. the disc. Two detectors (4R,4L) are fitted in a preset spacing along the first track (2). An evaluator (14) recognises a relative forward or backward movement between the detectors and the disc. A series-parallel data converter (12) is supplied with data from one or the other detector in dependence of the recognised relative motion, as a response to the evaluator output signal. The series data are shifted by the converter in one of two opposite directions, after their recognition. The series data are transmitted as parallel data with a preset number of bits, after the converter shifting. USE/ADVANTAGE - For control of overshifting and position holding, with reduced number of detectors and precise coded signal for absolute position.