Patent ID: 7839140

Claim:
A position detector arrangement for detecting a position of a packaging material with magnetic marking, comprising a sensor assembly comprising a plurality of magnetic sensor units each comprising an output providing an output signal, wherein said magnetic sensor units are arranged in at least two sensor unit pairs, the sensor units of each pair are arranged with opposite sensitivity directions, and said sensor units are arranged to sense magnetic markings of said packaging material; a signal processing assembly connected to said outputs of said magnetic sensors comprising a combiner arranged to aggregate said output signals of said sensors to an aggregated signal; a detector arranged to determine said position of said packaging material from said aggregated signal; a first magnetic compensation sensor unit arranged with its sensitivity direction perpendicular to said sensitivity directions of said plurality of magnetic sensor units; and a second magnetic compensation sensor unit arranged with its sensitivity direction perpendicular to said sensitivity directions of said plurality of magnetic sensor units and said first magnetic compensation sensor unit.