DEVICE FOR DETERMINING AND/OR MONITORING A PREDETERMINED MATERIAL LEVEL IN A CONTAINER

摘要

The determination and/or monitoring of a predetermined material level in a container is effected with the help of a material level sensor which contains a mechanical oscillatory structure, an electromechanical excitation transducer and two electromechanical reception transducers. The mechanical oscillatory structure is secured at the height of the predetermined material level in such a way that it comes into contact with the material when said material reaches the predetermined material level. Each reception transducer is connected to the input of an assigned circuit channel, which contains an amplifier circuit, the output of which is connected to the excitation transducer and which is so constructed that the mechanical oscillatory structure is excited to produce oscillations with its natural resonance frequency. The two circuit channels are activated alternately by means of a control circuit. Furthermore, each circuit channel contains a measuring signal transducer which produces a measuring signal which on the one hand contains the information about the frequency of the output signal of the amplifier circuit, and to which on the other hand an identifier assigned to the circuit channel has been added, said identifier being different from the identifier assigned to the other circuit channel.