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

摘要

A weighing cell based on the principle of electromagnetic force compensation. A permanent magnet system is mounted on a base part and includes an air gap within which is suspended a coil that is connected to a load receiver through a force-transmitting mechanism. The coil carries an electrical compensation current when the weighing cell is in operation. An optoelectronic position sensor is also included, and its signal corresponds to the deflection of the coil from a zero position which occurs as a result of placing a load on the load receiver. A closed-loop controller regulates the compensation current in response to the sensor signal in such a way that the coil and the load receiver that is connected to it are returned to their zero position by the electromagnetic force that is acting between the coil and the permanent magnet.