Asymmetric Echo Search Window for Fill Level Monitoring
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Solution Overview
Problem
Existing fill level measurement methods using travel time measurement face challenges in accurately identifying the wanted echo signal, especially with installed objects and during changes in process conditions, leading to potential overfilling or incorrect fill level readings.
Innovation Solution
A method that involves transmitting signals towards a medium, registering echo signals, and using an echo search algorithm to track changes in position and amplitude within a defined search window to ascertain the wanted echo signal, while maintaining its position and amplitude for accurate fill level measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If static echo search algorithms are used to identify the wanted echo signal, then the measurement process is simple and fast, but the accuracy deteriorates when installed objects or process conditions change
Solution Approach 1:
The patent applies dynamics by transitioning from static echo search algorithms to dynamic echo search algorithms that adapt to changing process conditions. The system continuously adjusts the search criteria based on real-time echo signal characteristics, allowing accurate identification of the wanted echo even when installed objects or medium properties change during operation.
Solution Approach 2:
The patent implements feedback mechanisms where the system monitors echo signal characteristics and uses this information to refine subsequent search algorithms. By analyzing the feedback from echo signals, the system can identify patterns and adjust its search strategy, improving accuracy while maintaining measurement speed through iterative optimization.
2Measurement precision
If dynamic echo search algorithms with historical information are applied, then the echo signal identification accuracy improves, but the device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-processing echo signals and storing characteristic data in a database before actual measurement occurs. This pre-prepared information serves as a reference for rapid identification during operation, reducing the computational burden during real-time measurement while maintaining high accuracy through historical pattern recognition.
Solution Approach 2:
The patent segments the echo search process into distinct phases: signal acquisition, feature extraction, pattern matching, and identification. By dividing the complex algorithm into modular segments, the system manages computational complexity more effectively while maintaining the benefits of dynamic adaptation and historical data utilization.
3Ease of operation
If the first echo with largest amplitude is selected as wanted echo, then the measurement process is simple, but measurement errors occur when installed objects create stronger reflections
Solution Approach 1:
The patent applies local quality by analyzing different characteristics of echo signals at different positions and times. Instead of uniformly selecting the largest amplitude echo, the system evaluates local features such as echo shape, timing relative to expected fill level, and consistency with historical data, allowing it to distinguish between desired reflections from the fill surface and spurious reflections from installed objects.
Solution Approach 2:
The patent introduces intermediary evaluation criteria that mediate between the raw echo signals and the final identification decision. These intermediary parameters act as filters and validators, comparing echo characteristics against expected patterns and historical data to determine whether a reflection corresponds to the actual fill level or is an artifact from installed objects, thereby improving reliability without sacrificing ease of operation.
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 provides a more stable and reliable method for identifying the wanted echo signal, reducing errors and maintaining accurate fill level measurements even under changing conditions, thus preventing overfilling or incorrect readings.
Implementation Method 1
microwaves sent by means of an antenna in the direction of the fill substance are reflected at the surface of the fill substance and then received back after a distance dependent, travel time
Implementation Method 2
From the travel time of the wanted echo, there results, in the case of a known propagation velocity of the transmission signals, directly the distance between the surface of the fill substance and the transmission element
Data Source
AI summary
A method for ascertaining and monitoring fill level of a medium in a container by means of a field device by a travel time measuring method, wherein transmission signals are transmitted in the direction of the medium and reflection signals are received, wherein received reflection signals are registered as echo signals in an echo function dependent on travel time or travel distance, wherein position and/or amplitude at least of a wanted echo signal in the echo function are/is ascertained by means of an echo search algorithm and a continuous echo tracking of changes of position and/or of changes of amplitude of the wanted echo signal in the echo function is performed in a defined search window, wherein position and/or amplitude at least of a wanted echo signal is maintained, in case no wanted echo signal is ascertained in the search window, wherein from position and/or amplitude at least of a wanted echo signal, fill level is ascertained, and wherein a measured value of fill level is output. For this, an asymmetric search window is used for ascertaining the wanted echo signal.