Multiturn rotary encoder

Abstract

A multiturn rotary encoder includes: a single-turn unit, including a code carrier that is able to be scanned by a single-turn scanner in order to generate single-turn position signals, and a single-turn evaluation unit for processing the single-turn position signals to form at least one single-turn code word that indicates the absolute position of an input shaft within one revolution; a first multiturn unit dependent on a power supply, including at least a first multiturn code carrier that is able to be scanned by a first multiturn scanner in order to generate first multiturn position signals, and a first multiturn evaluation unit for processing the first multiturn position signals to form a first multiturn code word that indicates the number of revolutions executed by the input shaft; and a second multiturn unit independent of a power supply, including at least a second multiturn code carrier that is able to be scanned by a second multiturn scanner in order to generate second multiturn position signals, and a second multiturn evaluation unit for processing the second multiturn position signals to form a second multiturn code word which likewise indicates the number of revolutions executed by the input shaft. The value of the first multiturn code word of the first multiturn unit in an initialization phase after the power supply of the multiturn rotary encoder has been switched on is able to be referenced with the value of the second multiturn code word.