Vibronic Sensor Adaptive Filter Phase Shift Control
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Solution Overview
Problem
Vibronic sensors face challenges in robustness, particularly with regards to external vibrations, due to the dependency on the selectivity of filters used in signal processing and evaluation, which can lead to loss of resonance and instability in control loops.
Innovation Solution
The implementation of an adaptive filter in the electronics unit allows for the adjustment of filter characteristics to set a target phase shift between the excitation and received signals, enhancing robustness and adaptability to different applications, including digital and analog oscillating circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed filter characteristics are used in the electronics unit, then the device complexity is reduced, but the robustness against external vibrations deteriorates due to loss of resonance and control loop instability
Solution Approach 1:
The patent applies the dynamics principle by implementing an adaptive filter whose characteristics (center frequency and bandwidth) are dynamically adjusted during operation. The filter transitions from a fixed configuration to a dynamic one where parameters are continuously adapted based on the detected oscillation frequency of the mechanically oscillatable unit. This allows the filter to maintain optimal performance and robustness against external vibrations while tracking the resonant frequency changes.
Solution Approach 2:
The patent implements parameter changes by modifying the filter characteristics (center frequency and bandwidth) based on the detected oscillation frequency. The electronics unit automatically adjusts these parameters to maintain the target phase shift between excitation and received signals, thereby preserving measurement accuracy and control loop stability under varying operating conditions and external vibrations.
2Reliability
If the filter selectivity is increased to improve robustness, then the robustness against external vibrations is improved, but the measurement precision deteriorates due to phase shift variations affecting resonance detection
Solution Approach 1:
The patent resolves this contradiction by dynamically adjusting the filter's center frequency to match the detected oscillation frequency of the mechanically oscillatable unit. This frequency tracking ensures that the filter remains tuned to the resonant signal even when external vibrations cause frequency shifts, thereby maintaining both robustness and measurement precision simultaneously.
Solution Approach 2:
The patent employs feedback by using the detected oscillation frequency information to continuously adjust the adaptive filter parameters. The electronics unit monitors the received signal, determines the actual oscillation frequency, and feeds this information back to the filter configuration, creating a closed-loop system that maintains optimal filter settings for accurate resonance detection despite external disturbances.
3Adaptability or versatility
If adaptive filter characteristics are implemented, then the adaptability to different applications is improved, but the device complexity increases due to additional control mechanisms
Solution Approach 1:
The patent applies universality by designing the adaptive filter to serve multiple functions: it acts as a bandpass filter for signal selection, a frequency tracker for resonance detection, and a phase shift controller for excitation synchronization. This multi-functionality is achieved through a unified adaptive filtering approach that handles various measurement tasks (fill level, density, viscosity) without requiring application-specific filter configurations, thereby reducing overall system complexity despite the adaptive capabilities.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in a more robust vibronic sensor capable of maintaining stability and accuracy under external vibrations, with the ability to set phase shifts independently of disruptive influences and adapt to various applications, ensuring reliable operation across a range of conditions.
Implementation Method 1
a piezoelectric drive or an electromagnetic drive
Implementation Method 2
an electromagnetic drive
Implementation Method 3
resonance frequencies, ie a frequency shift
Data Source
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Figure 2
AI summary
Disclosed is a vibronic sensor (1) for determining and/or monitoring at least one process variable of a medium (2) in a container (3), said sensor at least comprising: a unit (4) which can oscillate mechanically; a driving/receiving unit (5); and an electronic unit (6), wherein: the driving/receiving unit (5) is designed to excite, by means of an electrical excitation signal (UA), mechanical oscillations in the unit (4) which can oscillate mechanically and is designed to receive the mechanical oscillations of the unit (4) which can oscillate mechanically and to convert them into an electrical receiving signal (UE); the electronic unit (6) is designed to generate the excitation signal (UA) on the basis of the receiving signal (UE) and to determine the at least one process variable from the receiving signal (UE); the electronic unit (6) comprises at least one adaptive filter (7); and wherein the electronic unit (6) is designed to set the filter characteristic of the adaptive filter (7) in such a way that there is a target phase shift (Φsoll) between the excitation signal (UA) and the receiving signal (UE).