Measurement of a multi-pole encoder with a magnetic and coordinate measuring machine

Abstract

In this work, the magnetic field and the geometry of a multi-pole encoder (pole wheel) are measured with a magnetic and coordinate measuring machine. First, the geometry of the pole wheel is scanned optically, and mechanical manufacturing tolerances are determined. Then, the magnetic field is measured relative to the geometry of the pole wheel. These results show the characteristic of the magnetic field of regular marks and of the reference mark (missing mark). This information is used to determine magnetic parameters of the pole wheel such as the remanence of the magnetized layer, or the angle between two regular marks. Moreover, the symmetry of the magnetic field is compared with the symmetry of the geometry of the pole wheel.