Magnetic encoder for absolute length measurement

摘要

The encoder consists of two parallel tracks (1) of alternate North and South magnetised elements. A sensor, e.g. Hall probe, is connected by a lead (3) to a processor (4) and display (5). The encoder has a single-turn track with alternating North and South pole elements for fine position sensing. The second track is a multi-turn track with cyclic sequential code for coarse position sensing. The sensor has two probes for the single-turn track with half the encoder spacing and a number of probes (2N) for the multi-turn track at half the encoder spacing.