Measuring Device for Determining and/or Monitoring at Least One Process Variable

1 - 10 . (canceled)

11 . A measuring device for determining and/or monitoring at least one process variable, comprising:

a sensor unit having at least one sensor sensitive for the process variable;

a first electronics unit, which is associated with an energy supply unit and which has a first microcontroller; and

a second electronics unit, which is associated with said sensor unit and has a second microcontroller, and which is connected with said first electronics unit via a galvanically isolated transmission unit for energy- and data transmission, wherein:

first microcontroller produces at least one signal, which can vary in at least one characteristic, and supplies the signal to said transmission unit, said at least one signal controls energy- and data transmission; and

said the first microcontroller and/or said second microcontroller determines at least one current operating parameter, and

the first microcontroller sets at least one characteristic of the signal as a function of the operating parameter.

12 . The measuring device as claimed in claim 11 , wherein:

said first microcontroller adapts at least one characteristic of said at least one signal to a current operating state of the measuring device and/or sets the characteristic in such a manner that the efficiency of energy transmission is optimized.

13 . The measuring device as claimed in claim 11 , wherein:

the characteristic of said at least one signal set by said first microcontroller is the frequency of said at least one signal and/or the pulse duration to pause duration ratio.

14 . The measuring device as claimed in claim 11 , wherein:

said transmission unit includes at least one transformer.

15 . The measuring device as claimed in claim 14 , wherein:

said transmission unit is a push pull converter.

16 . The measuring device as claimed in claim 11 , wherein:

said first microcontroller registers a present input power of said transmission unit;

said second microcontroller registers a current output power of said transmission unit; and

said first microcontroller and/or said second microcontroller ascertains from the registered input power and the registered output power the present efficiency of the energy transmission.

17 . The measuring device as claimed in claims 14 , wherein:

said first microcontroller and/or said second microcontroller determines from the ascertained efficiency whether a coil break is present in said at least one transformer and produces in the case of a coil break a corresponding defect report.

18 . The measuring device as claimed in claim 11 , wherein:

said first microcontroller has different operating modes, which are characterized by certain values of at least one characteristic of said at least one signal;

an operating mode is associated with each operating state of the measuring device; and

said first microcontroller sets the operating mode as a function of the current operating state.

19 . The measuring device as claimed in claim 11 , wherein:

said first microcontroller registers an identification of said sensor unit, and sets, as a function of said sensor unit present, the at least one characteristic of said at least one signal in such a manner that the energy transmission is matched to the energy requirement of said respective sensor unit.

20 . The method for operating a measuring device for determining and/or monitoring at least one process variable, which comprises at least one sensor unit having at least one sensor sensitive for the process variable, a first electronics unit, which is associated with an energy supply unit and which has a first microcontroller, and a second electronics unit, which is associated with the sensor unit and has a second microcontroller, and which is connected with the first electronics unit via a galvanically isolated transmission unit for energy- and data transmission, comprising the steps of:

producing at least one signal having at least one variable characteristic;

feeding said at least one signal to the transmission unit; and

determining at least one current operating parameter by controlling energy- and data transmission by the signal, and at least one characteristic of the signal is set as a function of the operating parameter.