Displacement sensor for contactlessly measuring a position by means of a plurality of magnetic field sensors arranged in series

Abstract

The present invention relates to a displacement sensor for contactlessly measuring a position of a magnet relative to a reference point. The displacement sensor comprises the magnet which can be displaced along a movement axis, a plurality of magnetic field sensors which are arranged in series and which are arranged parallel with the movement axis of the magnet and a calculation unit for forming a position signal which indicates the position of the magnet relative to the reference point. The plurality of magnetic field sensors which are arranged in series are arranged in such a manner that the displacement measurement ranges of adjacent magnetic field sensors overlap in an overlap range. The calculation unit is constructed in such a manner that, if the position of the magnet is contained in an overlap range, it forms the position signal on the basis of output signals which are output by the magnetic field sensors whose displacement measurement ranges overlap in the overlap range; and, if the position of the magnet is not contained in an overlap range, it forms the position signal on the basis of the output signal which is output by the magnetic field sensor, in the displacement measurement range of which the magnet is located. The overlap range between two displacement measurement ranges of adjacent magnetic field sensors is selected in such a manner that the total error of the position signal formed by the calculation unit in that overlap range is smaller than a maximum tolerable error.

Description

technical field [0001] The present invention relates to a displacement sensor for contactless measurement of the position of a magnet based on a plurality of magnetic field sensors arranged in series, in particular to a displacement sensor with a displacement range several times greater than an individual magnetic field sensor. [0002] In the displacement sensor according to the invention, the accuracy of the position signal output by the displacement sensor and indicating the position of the magnet relative to the reference point is intended to be below a maximum permissible error over the entire displacement range. [0003] A typical example of a magnetic field sensor is a Hall sensor. As an example of a magnetic field sensor, the present invention is described with reference to a Hall sensor, but is not limited thereto. Background technique [0004] Hall sensors are used in many cases for controlling machine tools, in automation technology, robotics and in automatic par...

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Problems solved by technology

At the two ends 103 and 104 of the displacement measurement range, the variation of the measurement signal and thus the measurement error becomes larger; the linear relationship between the output signal 102 of the sensor and the position of the magnet disappears because the output signal 102 indicates the position of the magnet the precision of the

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