Patent ID: 6653620
Filing Date: 2003-11-25
Classification: B62D,G01D

Abstract:
A method for evaluating a position signal generated by a position measuring system having an encoder with at least one code track bordered by at least one non-code track, wherein the encoder is interposed between a light source and a light sensor and moves relative to the light source and the light sensor, wherein the at least one code track transmits light from the light source onto the light sensor when the encoder is in a given position relative to the light source, wherein the at least one non-code track prevents light from the light source onto the light sensor when the encoder is in any position relative to the light source, wherein the light sensor generates the position signal as a function of the transmitted light received by transducers of the light sensor, the method comprising the steps of:(A) determining brightness of a code track signal contained in the position signal, the code track signal being generated by light sensor transducers assigned to a code track of the encoder; (B) determining brightness of a non-code track signal contained in the position signal, the non-code track signal being generated by light sensor transducers assigned to a non-code track of the encoder; (C) determining relative brightness between the code and non-code track signals; and (D) determining whether the light sensor transducers assigned to the code track of the encoder are exposed to the light source as a function of the relative brightness between the code and non-code track signals.