CPC G01F 23/2967 (2013.01) [G01H 11/06 (2013.01); G01N 9/002 (2013.01); G01N 11/16 (2013.01); G01N 29/42 (2013.01); G01N 29/022 (2013.01); G01N 2009/006 (2013.01); G01N 2291/014 (2013.01); G01N 2291/02818 (2013.01); G01N 2291/02836 (2013.01)] | 18 Claims |
1. A vibronic sensor for determining a process variable of a medium, comprising:
a mechanically oscillatable unit;
a driving/receiving unit embodied to excite the mechanically oscillatable unit with an electrical excitation signal to cause the mechanically oscillatable unit to mechanically oscillate and further embodied to receive mechanical oscillations of the mechanically oscillatable unit and transduce the mechanical oscillations into an electrical, received signal; and
an electronics unit including:
an adaptive filter having an input signal and an output signal, the adaptive filter further having a filter characteristic suitable to set a phase shift between the input signal and the output signal; and
a phase control unit configured to control the filter characteristic of the adaptive filter such that a predetermined phase shift is present between the input signal and the output signal of the adaptive filter,
wherein the vibronic sensor is embodied to operate in a first operating mode during which:
the driving/receiving unit excites the mechanically oscillatable unit with an electrical excitation signal to cause the mechanically oscillatable unit to mechanically oscillate;
the phase control unit is paused; and
the filter characteristic of the adaptive filter is held constant,
wherein the vibronic sensor is further embodied to operate in a second operating mode during which:
the driving/receiving unit interrupts the exciting of the mechanically oscillatable unit;
the driving/receiving unit to receives mechanical oscillations of the mechanically oscillatable unit and transduces the mechanical oscillations into the electrical, received signal;
to the phase control units sets a value of the filter characteristic of the adaptive filter such that the predeterminable phase shift is present between the excitation signal and the received signal; and
the electronics unit determines from the received signal the process variable, and
wherein the electronics unit is further embodied to execute alternately and successively the first operating mode and the second operating mode.
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