초록 ▼

Described is a method for detecting and/or for monitoring the level of a medium stored in a vessel and in particular to a method for diagnosing the functionality of the electromechanical oscillation unit of a vibration level gauge. An electromechanical transducer of the electromechanical oscillation

Described is a method for detecting and/or for monitoring the level of a medium stored in a vessel and in particular to a method for diagnosing the functionality of the electromechanical oscillation unit of a vibration level gauge. An electromechanical transducer of the electromechanical oscillation unit of a vibration level gauge is supplied with an electric wave signal. The frequency of which is beyond the resonance frequency range of the electromechanical oscillation unit and is thus not adapted to actuate the oscillatory portion as for example an oscillating rod probe or tuning fork, so that the electric wave signal is converted into mechanical oscillations without actuating the oscillatory portion. Subsequently, the converted mechanical oscillations will be recorded using the at least one electromechanical transducer of the electromechanical oscillation unit, which reconverts the mechanical oscillations into an electric wave signal. These recorded electric wave signals will then be analyzed to derive therefrom any transmission characteristics of the electromechanical transducer by comparing at least one of the signal characteristics of the reconverted electric wave signal with typical signal characteristics determined before. Finally, a status information will be edited subject to the analysis of the transmission characteristics.

대표청구항 ▼

The invention claimed is: 1. A method for diagnosing a functionality of an electromechanical oscillation unit of a vibrating level gauge, comprising the steps of: supplying at least one electromechanical transducer of the electromechanical oscillation unit with an electric wave signal, a frequency

The invention claimed is: 1. A method for diagnosing a functionality of an electromechanical oscillation unit of a vibrating level gauge, comprising the steps of: supplying at least one electromechanical transducer of the electromechanical oscillation unit with an electric wave signal, a frequency of which is beyond a resonance frequency range of the electromechanical oscillation unit and is not adapted to cause resonance of an oscillatory portion of the electromechanical oscillation unit so that the electric wave signal is converted into mechanical oscillations; recording the converted mechanical oscillations using the at least one electromechanical transducer of the electromechanical oscillation unit, which reconverts the mechanical oscillations into the electric wave signal; analyzing transmission characteristics of the electromechanical transducer by comparing at least one of signal characteristics of the reconverted electric wave signal with predetermined signal characteristics; and adjusting a status information subject to an analysis of the transmission characteristics. 2. The diagnostic method according to claim 1, wherein a plurality of shunted electromechanical transducers are supplied with an electric wave signal. 3. The diagnostic method according to claim 1, wherein diagnosis is continuously performed during an operation of the vibrating level gauge. 4. The diagnostic method according to claim 1, wherein diagnosis is performed after initiating a testing interval. 5. The diagnostic method according to claim 1, wherein the analysis of the reconverted electric wave signal is accomplished by a control unit of the vibrating level gauge. 6. The diagnostic method according to claim 5, wherein the analysis of the transmission characteristics is performed by (i) supplying the electromechanical transducer of the electromechanical oscillation unit with a plurality of electric wave signals having different frequencies respectively, all of which are beyond the resonance frequency range of the electromechanical oscillation unit and are not adapted to excite the oscillatory portion of the electromechanical oscillation unit, and (ii) processing the received signal characteristics of these electric wave signals to form one common signal characteristic being representative for the plurality of electric wave signals. 7. The diagnostic method according to claim 1, wherein, in the analyzing step, at least an amplitude of the electric wave signal is compared with a predetermined value. 8. The diagnostic method according to claim 7, wherein, in the analyzing step, a phase shift of the electric wave signal is compared with a further predetermined value. 9. The diagnostic method according to claim 1, wherein the conversion of the electric wave signal into mechanical oscillations is accomplished using at least one piezoelectric transmit-transducer of the electromechanical transducer. 10. The diagnostic method according to claim 9, wherein the reconversion of the mechanical oscillations into the electric wave signal is accomplished using at least one piezoelectric receive-transducer of the electromechanical transducer. 11. The diagnostic method according to claim 10, wherein the piezoelectric transmit-transducer and the piezoelectric receive-transducer are stacked and mechanically coupled to one another to form the electromechanical transducer. 12. The diagnostic method according to claim 10, wherein the piezoelectric transmit-transducer and the piezoelectric receive-transducer are one common component. 13. The diagnostic method according to claim 1, wherein at least one sensor characteristic of the vibrating level gauge is recorded, which is not necessary for the switching function. 14. The diagnostic method according to claim 13, wherein at least one type of the recorded characteristics is stored. 15. The diagnostic method according to claim 13, wherein at least one of (i) the recorded characteristics and (ii) the global diagnostic value is analyzed with respect to overstepping of predetermined thresholds. 16. The diagnostic method according to claim 13, wherein at least the signal characteristics of at least one of (i) the reconverted electric wave signals and (ii) the global diagnostic value are digitally read out via a two-wire loop. 17. The diagnostic method according to claim 13, wherein at least one of (i) extreme signal and (ii) sensor characteristics and the predetermined values are stored in a non-volatile memory. 18. The diagnostic method according to claim 13, wherein the at least one sensor characteristic is a characteristic of a group of sensor characteristics consisting of temperature, capacity, impedance, inductance, pressure, operating time and humidity. 19. The diagnostic method according to claim 18, wherein at least one recorded signal characteristic and at least one sensor characteristic are combined and processed to form one global diagnostic value, which is representative of a qualitative status of the vibrating level gauge. 20. The diagnostic method according to claim 19, wherein the at least one recorded signal characteristic and the at least one sensor characteristic are processed to derive one global diagnostic value using at least one processing arrangement of a group of processing arrangements consisting of mathematical methods, statistical methods, tables, Fuzzy-algorithms and neural networks. 21. A self-diagnosing vibrating level gauge comprising: an electromechanical oscillation unit having an oscillatory portion and a first transducer receiving a first electric wave signal having a frequency beyond a resonance frequency range of the electromechanical oscillation unit, the first transducer converting the electric wave signal into mechanical oscillations, wherein the first transducer is one of an electromechanical transmit transducer and an electromechanical transmit-receive-transducer; a second transducer reconverting the mechanical oscillations into a second electric wave signal, the second transducer being one of a receive-transducer and a transmit-receive-transducer; and a control unit analyzing transmission characteristics of the first transducer by comparing at least one characteristic of the second electric wave signal to predetermined typical characteristics.