The present disclosure relates to an apparatus for determining and/or monitoring a predetermined fill level of a medium in a containment, comprising a sensor unit and an electronics unit. The electronics unit includes a limiting unit embodied to limit an electrical current or an electrical voltage in at least one portion of the electronics unit, a switching unit embodied to control a process switch having at least first and second switch states, and a signal transformation unit embodied to transform a dynamic, electrical input signal into a static, electrical output signal, and wherein the static output signal flows through at least one component of the electronics unit. Furthermore, the electronics unit is embodied to supply the sensor unit with an excitation signal, to receive from the sensor unit a received signal, to determine and/or to monitor whether the predetermined fill level has been reached, and to produce at least one control signal.

An electrical device (10, 13), in particular a power transformer (13), a shunt reactor, or an on-load tap changer (10), comprises a housing (101, 131) that is filled or fillable with insulation oil (11, 11); and a sensor (12) that comprises a piezo element (16) in the housing (101, 131) on a level with a minimum fill level (19, 19) of the insulation oil (11, 11); and an evaluation device (18) that is connected to the piezo element (16); wherein the evaluation device (18) is formed such that it can induce an oscillation of the piezo element (16); and it can determine the fill level from a measurement of a characteristic of the oscillation, in particular the half-life period of the amplitude of the oscillation.

A vibronic sensor for determining and/or monitoring at least one process variable of a medium in a container. The sensor at least comprising: a unit which can oscillate mechanically; a driving/receiving unit; and an electronic unit. The driving/receiving unit is designed to excite, by an electrical excitation signal, mechanical oscillations in the unit which can oscillate mechanically and is designed to receive the mechanical oscillations of the unit which can oscillate mechanically, and to convert the mechanical oscillations into an electrical receiving signal. The electronic unit is designed to generate the excitation signal on the basis of the receiving signal and to determine that at least one process variable from the receiving unit. The electronic unit comprises at least one adaptive filter; and the electronic unit is designed to set the filter characteristic of the adaptive filter in such a way that there is a target phase shift between the excitation signal and the receiving signal.

A method to determine and/or monitor at least one process variable of a medium with at least one vibration-capable unit. The vibration-capable unit is excited to mechanical vibrations by means of an electrical excitation signal of an adjustable frequency; wherein the mechanical vibrations are transduced into a received electrical signal, which is characterized at least by a frequency and/or a phase and/or an amplitude. The excitation signal is generated based on the received signal; wherein the voltage values of the received signal are sampled at specified predetermined points in time, starting from the excitation signal. The real part and the imaginary part of the received signal are determined from the sampled voltage values of the received signal by means of a Goertzel algorithm; wherein at least one Goertzel coefficientin particular the number of the sample values and/or an operating frequency and/or a sample frequencyis provided for performing the Goertzel algorithm. At least the current phase and/or the current amplitude of the received signal are calculated from the real part and the imaginary part of the received signal; wherein the frequency of the excitation signal is adjusted such that a predeterminable phase shift is present between the excitation signal and the received signal; and wherein the at least one process variable is determined.

The present disclosure includes a method for monitoring the condition of a component of an electromechanical resonator having a piezoelectrical element which can be excited to mechanical vibration using an electrical excitation signal and the mechanical vibrations of which can be received in the form of an incoming electrical signal. The method steps performed at a first point and a second point in time, including determining an amplification factor of the electromechanical resonator, determining a mechanical quality resonator, and establishing an electromechanical efficiency resonator at least from the amplification factor and the mechanical quality. A change over time in the electromechanical efficiency is calculated from the first point to the second point in time, the change over time in the electromechanical efficiency is compared with a pre-definable threshold, and a condition indicator is determined from the comparison.

The present disclosure relates to a method and corresponding sensor for determining density and/or viscosity of a medium using a vibronic sensor. An oscillatable unit is excited using an electrical excitation signal to execute mechanical oscillations, and the mechanical oscillations of the mechanically oscillatable unit are received and transduced into an electrical, received signal. The excitation signal is produced based on the received signal such that at least one predeterminable phase shift is present between the excitation signal and the received signal, wherein a frequency of the excitation signal is determined from the received signal at the predeterminable phase shift. A damping and/or a variable dependent on the damping are/is determined from the received signal at the predeterminable phase shift. From the damping and/or the variable dependent on the damping and from the frequency of the excitation signal, the density and/or the viscosity of the medium are/is ascertained.

Apparatus for monitoring a predetermined fill level of a medium in a container, including a mechanically oscillatable unit, a driving/receiving unit for exciting the mechanically oscillatable unit to execute mechanical oscillations and for receiving the oscillations of the mechanically oscillatable unit, and an electronics unit for producing an electrical exciter signal and for evaluating an electrical, received signal. The electronics unit is embodied to excite the mechanically oscillatable unit by means of the driving/receiving unit to execute mechanical oscillations within a fixedly predetermined, narrow frequency band with discrete, sequentially following, exciter frequencies, wherein the frequency band contains the resonant frequency of the mechanically oscillatable unit in the case of an oscillation under standard conditions, and the electronics unit is embodied to detect whether, within the predetermined frequency band an oscillation of the mechanically oscillatable unit occurs, whose amplitude exceeds a predetermined threshold value.

The invention provides a method for configuring for use a vibrating fork level switch having a dry fork frequency DFF. The method involves establishing a wet fork frequency WFF and combining this with the DFF to configure the switch for use in media of differing densities.

An add-on module for a sensor, such as a fill and/or limit level sensor, comprising a coupling unit, which is arranged to be communicatively couplable to at least one predetermined sensor, and a control unit, which is configured to enable and/or disable data processing of the at least one predetermined sensor. Furthermore, the invention also relates to a sensor unit for detecting a fill level and/or limit level, comprising at least one sensor, and such an additional module, as well as a method for controlling such a sensor unit.

A system for determining and/or monitoring a process variable of a medium in a container, comprising a sensor module with an oscillatable unit, which is arranged in such a manner in the container that the oscillatable unit extends to a defined immersion depth in the medium, or that the oscillatable unit is placed at the height of the predetermined fill level, a tubular extension and/or a temperature reduction unit of a defined length, a contacting module and an electronics module, composed of an exciter/receiving unit, which excites the oscillatable unit to execute oscillations and receives the oscillations of the oscillatable unit. Two electrical coupling paths are associated with the electronics module, and a control/evaluation unit, which based on at least one oscillation variable of the oscillations or based on a change of an oscillation variable of the oscillations, provides information concerning the process variable or the reaching of the predetermined fill level. The sensor module and the electronics module are either electrically connected directly with one another, wherein one of the two electrical coupling paths is activated, or wherein the sensor module and the electronics module are indirectly electrically connected with one another via the contacting module, and wherein both coupling paths are activated.