Weighing cell based on the principle of electromagnetic force compensation with optoelectronic position sensor

Weighing cell based on the principle of electromagnetic force compensation, comprising:

• a stationary base part;
• a load receiver constrained to the base part with guided mobility and serving to accept the weight force of a weighing load;
• a permanent magnet system with an air gap;
• a coil that is movably suspended in the air gap and, when operating in a weighing mode, conducts a flow of a compensation current;
• a force-transmitting mechanical connection between the load receiver and the coil;
• an optoelectronic position sensor, including:
• a light source and a light receiver arranged facing each other on opposite sides of a space interval located therebetween, such that center points of the light source and the light receiver define an optical axis, and
• a shutter vane that is solidly connected to the force-transmitting connection, the shutter vane movably arranged at a shutter distance on the optical axis between the light source and the light receiver, the shutter distance lying in a subsection of the space interval that extends outward from the light receiver over no more than one-third of the total space interval;
• wherein, the light receiver is adapted to generate a position sensor signal corresponding to a deflection of the shutter vane from a zero position which is caused by placing the load onto the load receiver;
• and
• a controller that functions to regulate the compensation current in response to the position sensor signal in such a way that the shutter vane and the movable parts of the weighing cell connected to the shutter vane are returned to the zero position by an electromagnetic force between the coil and the permanent magnet system.