Patent ID: 7164120
Filing Date: 2007-01-16
Classification: G01D

Abstract:
1. A position measuring instrument, comprising: a periodic incremental graduation comprising a plurality of graduation periods within one measurement range; a reference marking disposed within said measurement range and integrated with said incremental graduation; an arrangement of detector elements positioned over at least a length of said measurement range and used for scanning said periodic incremental graduation over at least said length of said measurement range for generating a plurality of periodic scanning signals of which at least one is modified locally by said reference marking and is associated with one of said detector elements; and an evaluation device that receives said periodic scanning signals, determines a first absolute position within one of said plurality of graduation periods and detects said at least one scanning signal, modified by said reference marking, from said plurality of periodic scanning signals and determines a second absolute position of said reference marking within said length of said measurement range while said at least one scanning signal modified by said reference marking defines one specific location of said one of said detector elements.