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The invention pertains to a level measuring by an apparatus has oscillating fork (1) that is excited to oscillate by an oscillator circuit that, for example, is realized in the form of a series circuit consisting of an input amplifier (2), a band filter (3) and an output amplifier (4). An identifyin

The invention pertains to a level measuring by an apparatus has oscillating fork (1) that is excited to oscillate by an oscillator circuit that, for example, is realized in the form of a series circuit consisting of an input amplifier (2), a band filter (3) and an output amplifier (4). An identifying element (6) is assigned to the oscillating fork (1), with the identifying element transmitting the fundamental frequency of the oscillating fork (1) to the oscillator circuit (2, 3, 4) in coded form. In addition, the identifying element (6) transmits the fundamental frequency of the oscillating fork (1) to the control input of a frequency evaluation circuit (5), the input of which is connected to the output of the oscillator circuit (2, 3, 4). Consequently, the parameters of the band filter (3), as well as of the frequency evaluation circuit (5), are optimally adjusted to the fundamental frequency of the oscillating fork (1).

대표청구항 ▼

1. Apparatus for level measuring comprising: a mechanically oscillating sensor, having an identifying element assigned thereto and containing a coded individual value of a fundamental frequency of the mechanically oscillating sensor; an oscillator circuit that excites the mechanically oscillatin

1. Apparatus for level measuring comprising: a mechanically oscillating sensor, having an identifying element assigned thereto and containing a coded individual value of a fundamental frequency of the mechanically oscillating sensor; an oscillator circuit that excites the mechanically oscillating sensor, an output of the oscillator circuit being connected to an input of a frequency evaluation circuit; and further comprising a band filter connected to the identifying element; wherein the identifying element acts upon the band filter and defines its response based on the coded value; and whereby circuit parameters of the oscillator circuit can be influenced by the identifying element and the band. 2. Apparatus according to claim 1, wherein the oscillator circuit further comprises a series circuit consisting of an input amplifier, the band filter and an output amplifier. 3. Apparatus according to claim 2, wherein an output of the identifying element is connected to a control input of the band filter. 4. Apparatus according to claim 3, wherein the identifying element comprises a resistor, terminals of which are connected to the band filter. 5. Apparatus according to claim 2, wherein the identifying element comprises a memory. 6. Apparatus according to claim 5, wherein the band filter comprises a bandpass filter having a capacitor; and further comprising: a plurality of resistors having corresponding controllable switches, whereby ones of the resistors can be switched parallel to the capacitor the respective corresponding ones of the controllable switches; wherein control outputs of a microprocessor are connected to control inputs of the controllable switches; and the microprocessor is connected to the memory in which the fundamental frequency of the mechanically oscillating sensor is stored. 7. Apparatus according to claim 5, wherein the memory comprises an EEPROM. 8. Apparatus according to claim 1, wherein the identifying element acts upon the band filter and defines its frequency response based on the coded value. 9. Apparatus according to claim 1, wherein the identifying element acts upon the band filter and defines its phase response based on the coded value. 10. Apparatus according to claim 1, wherein the identifying element acts upon the band filter and defines its amplification factor based on the coded value. 11. Apparatus according to claim 1, wherein the oscillator circuit comprises a regenerative oscillator. 12. Apparatus according to claim 1, wherein the identifying element contains data regarding several oscillation modes of the mechanically oscillating sensor for improving a targeted excitation of a desired mode or for multi-mode operation of the mechanically oscillating sensor. 13. Apparatus according to claim 1, wherein the identifying element stores general data regarding the mechanically oscillating sensor. 14. Apparatus according to claim 13, wherein the general data includes ones of coatings, sensor materials, temperature range, sensor length, process connections and serial number. 15. Apparatus according to claim 14, further comprising a field bus system connected to the identifying element whereby a type of the mechanically oscillating sensor can be precisely identified from a control room. 16. Apparatus according to claim 13, wherein all stored data of the mechanically oscillating sensor are preserved when electronics are exchanged. 17. Apparatus according to claim 16, wherein the identifying element provides redundant storage of adjustments of the mechanically oscillating sensor whereby when old electronics are exchanged new electronics automatically adjust to the old electronics by reading the data stored in the identifying element.