Vibronic Sensor Adaptive Filter Phase Offset Control
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Solution Overview
Problem
Existing vibronic sensors face challenges in achieving high measurement accuracy and reliability, particularly in environments with external vibrations, due to limitations in filter selectivity and phase offset regulation.
Innovation Solution
The implementation of a vibronic sensor with an electronic unit that includes a first adaptive filter, allowing for the setting of a target phase offset between the excitation and reception signals, and a detection unit using quadrature demodulation for accurate phase offset determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an analog oscillation circuit with fixed filter characteristics is used, then the circuit is simple to implement, but the measurement precision deteriorates due to inability to adapt to different process variables and external vibrations
Solution Approach 1:
The patent implements a digital oscillation circuit where the filter characteristic can be dynamically adjusted based on the detected vibration frequency. The system automatically adapts the filter parameters to match the resonant frequency of the vibratable unit, enabling precise measurement across different process variables while maintaining circuit simplicity through software-based control.
Solution Approach 2:
The system changes the filter characteristic parameters (such as center frequency and bandwidth) according to the detected vibration frequency. By dynamically modifying these parameters, the circuit achieves high measurement precision for different process variables without requiring multiple fixed circuits, thus resolving the contradiction between simplicity and precision.
2Device complexity
If a fixed filter characteristic is used in the oscillation circuit, then the device complexity is low, but the reliability deteriorates due to sensitivity to external vibrations
Solution Approach 1:
The patent employs a dynamically adjustable filter whose characteristic automatically adapts to the vibration frequency of the vibratable unit. This dynamic adaptation allows the system to maintain reliable measurements under external vibrations by tracking the resonant frequency, while keeping the overall device complexity low through a single reconfigurable filter rather than multiple fixed filters.
Solution Approach 2:
The system uses feedback from the detected vibration frequency to automatically adjust the filter characteristic. This closed-loop control ensures that the filter remains tuned to the resonant frequency even under external vibrations, improving reliability without significantly increasing device complexity.
3Manufacturing precision
If the filter characteristic is fixed, then the manufacturing precision requirement is low, but the measurement precision deteriorates due to phase offset variations
Solution Approach 1:
The patent implements a digitally controllable filter whose characteristic parameters can be precisely adjusted in software. This allows the system to compensate for phase offset variations by dynamically changing the filter parameters to match the actual vibration frequency, achieving high measurement precision without requiring tight manufacturing tolerances on the filter components.
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 solution enhances measurement accuracy and reliability by allowing the sensor to operate robustly independent of external vibrations, and enables flexible operation across various applications and phase setting accuracies.
Implementation Method 1
an electromechanical transducer unit that can, in turn, be a piezoelectric drive or an electromagnetic drive
Implementation Method 2
an electromechanical transducer unit that can, in turn, be a piezoelectric drive or an electromagnetic drive
Implementation Method 3
set the filter characteristic of the adaptive filter such that a target phase offset is produced between the excitation signal and the reception signal
Implementation Method 4
a detection unit for determining a phase offset between the excitation signal and the reception signal and/or an amplitude of the reception signal using a quadrature demodulation
Implementation Method 5
a distinction is made between whether the vibratable unit is covered by the liquid or vibrates freely. The two states, the free state and the covered state, are thus differentiated—for example, based on different resonant frequencies
Data Source
AI summary
A vibronic sensor used to determine a process variable of a medium in a container comprises a mechanically vibratable unit, a drive/receiving unit, and an electronic unit. The drive/receiving unit excites mechanical vibrations in the mechanically vibratable unit via an electric excitation signal and receives the mechanical vibrations of the mechanically vibratable unit and convert same into an electric reception signal. The electronic unit is designed to generate the excitation signal on the basis of the reception signal and determine the process variable from the reception signal. The electronic unit includes an adaptive filter and is designed to set the filter characteristic of the adapter filter to produce a target phase offset between the excitation and reception signals. The sensor also has a detection unit to determine a phase offset between the excitation signal and the reception signal and/or the amplitude of the reception signal using a quadrature demodulation.