Absolute magnetic position encoder

An absolute magnetic position encoder for the measurement of linear or rotary motions of a body, characterized in that it includes the following:

• a magnet carrier (2) which is fixedly connected to the body and has a plurality of magnetic pole pairs which are formed by permanent magnets (5) and which are arranged in the direction of motion and whose alternately successive North and South poles form magnet segments, by the counting and resolution of which the position of the body is determined,
• a stationary sensor element arrangement (6) which for fine resolution of the magnet segments and for recognition of the direction of motion of the magnet carrier (2) includes at least two magnetosensitive sensor elements (7, 8) which use various magnetic field regions and of which at least one can be supplied at least at times with a low minimum current,
• a stationarily arranged Wiegand element (9) which is triggered at least by each second magnetic pole pair for the delivery of an electrical pulse, and
• an electronic arrangement (12) which includes a control logic and energy management circuit (20) and a counting unit (29) with a non-volatile storage means and which having regard to a signal delivered by the sensor element arrangement (6) and characterizing the direction of motion of the magnet carrier (2), adds the electrical pulses of the Wiegand element (9) to a count value stored in the non-volatile storage means or subtracts them therefrom, and
• a logic circuit (26) which is in data exchange relationship with the electronic arrangement (12) and which from the acquired count value and having regard to the signals delivered by the sensor element arrangement (6) calculates the instantaneous absolute position of the body,
• wherein a substantial part of the electrical power which is contained in the pulses delivered by the Wiegand element (9) serves at least in those periods of time in which an external power supply is absent for the power supply for the electronic arrangement (12) and for supplying the at least one magnetosensitive sensor (7, 8, 17) with the low minimum current so that the pulses of the Wiegand element (9) can also be counted and processed in that operating condition.