Weighing cell operating on the principle of magnetic power compensation with optoelectronic position sensor

Abstract

A weighing cell has a fixed base portion, a load receiver constrained to the base portion, a permanent magnet with air gaps, a coil hanged in the air gaps and guiding flowing of a compensation current, and a force transmission connection located between the load receiver and the coil. An optoelectronic position sensor includes a light source, a light receiver, and a shutter vane, wherein the shutter vane is connected to the connection, midpoints of the light source and the light receiver limit a light axis, the light source and the light receiver are arranged to be face to face opposite the gap, and the shutter vane is movably arranged at a shutter vane distance between the light source and the light receiver. The light receiver functions to generate a position sensor signal corresponding to a deflection of the shutter vane from a zero position which occurs as a result of placing a load onto a load receiver. A controller functions to regulate compensation current, the shutter vane and the movable parts of the weighing cell connected to the shutter vane are returned to the zero position by the electromagnetic force between a coil and permanent magnet system. The shutter vane distance is located at a sub-segment of the gap, and the sub-segment is adjacent to the light receiver and extends along the gap being not more than 1 / 3.

Description

technical field [0001] The invention relates to a scale or weighing unit which is based on the principle of magnetic compensation and which comprises an optoelectronic position sensor. Background technique [0002] The principle of electromagnetic force compensation is widely used in various weighing instruments used in commerce, industry and laboratories. This principle has the particular advantage that a weighing instrument of excellent measurement accuracy can be realized with it. Analytical scales based on the principle of electromagnetic force compensation have the ability, for example, to determine a weighing load of 100 grams with a measurement resolution of 0.01 milligrams, ie with an accuracy of one in ten million. [0003] The scale or weighing unit to which the present invention relates has: a fixed base part; a load receiver which is movably constrained to the base part and which is used to receive a weighing load; a permanent magnet system which is preferably m...

AI Technical Summary

Problems solved by technology

Therefore it requires a certain product to adjust each unit individually during the manufacturing process of weighing cells, which increases the manufacturing cost

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