Magnetic incremental coder module for theodolite, has sensors arranged on magnetic drums such that phase difference of signals output by sensors satisfy preset relations

摘要

Magnetic incremental coders (41,51) measure the azimuth and elevation angles of the vertical and horizontal axes (19,23) of a collimator telescope (25), relative to a leveling plate (17) and a socket (21). Magnetic sensors (44,54) of the coders are arranged on the magnetic drums (43,53). The phase difference between the signals output by the sensors, satisfy a predetermined relation. The phase difference between the signals from the magnetic sensors (44,54) of the coders arranged on the magnetic drums (43,53), satisfy a relation 2 pi P+ pi /j, where P is an integer, j denotes one of the k orders, and k is the number of orders of harmonic interference to be corrected.