Weighing cell based on the principle of magnetic compensation with photoelectric position sensor

Abstract

A weighing cell, with a fixed base part; a load receiver, constrained to the base part; a permanent magnet, with an air gap; a coil, suspended in the air gap, and directing the compensating current flow; and a force-transmitting connection, between the load receiver and the coil between. A photoelectric position sensor, comprising: a light source, a light receiver and a shutter plate, the plate being connected to the joint, the midpoint of the light source and the light receiver defining the optical axis, they are arranged opposite to each other at a distance, and the shutter plate can be moved between them Mobile arranged at the shutter distance. The optical receiver generates a position sensor signal corresponding to the offset of the optical shutter from the zero position. The offset is generated by the load in the load receiving chamber. The controller works to adjust the compensation current in response to the signal. The optical shutter is connected to the optical The movable part of the weighing unit of the paddle is returned to the zero position by means of the electromagnetic force between the coil and the permanent magnet system. The shutter distance is in spaced sub-sections that adjoin the light receivers and that sub-sections extend over no more than 1 / 3 of the spacing.

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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