There is provided a method for continual preparation of granular polycrystalline silicon using a fluidized bed reactor, enabling a stable, long-term operation of the reactor by effective removal of silicon deposit accumulated on the inner wall of the reactor tube. Each of the rest positions corresponds to one element selected from N elements, wherein the device is adapted to electrically and optically transmit data regarding trajectory of its movement and rest positions, including indications of an accelerometer connected to a position analysis and identification module. The data storage unit functions in combination with calibration information from the data carrier and is used by the processor to determine whether the consumables of the inserted cartridge renders a reliable measurement of analyte concentration. The piezoelectric layer is formed on the first main surface of the first layer.