Inductive Sensor Signal Compensation for Factor 1 Metal Detection
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Solution Overview
Problem
Conventional inductive proximity detectors operating in 'factor 1' mode face challenges with complex, expensive, and bulky designs, as well as limited performance and temperature drift issues, particularly when detecting various metallic materials.
Innovation Solution
The implementation of an LC resonant circuit with an excitation pulse generator, analog filtering and amplification of the response signal, and digital signal processing, along with a temperature compensation mechanism using a temperature sensor to enhance detection range and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple coils are used to achieve factor 1 detection, then detection performance is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges the functions of multiple coils into a single detection coil by combining it with a compensation coil. The compensation coil is wound in the opposite direction and positioned to compensate for temperature-induced changes in the detection coil's characteristics, achieving factor 1 detection with a unified structure rather than separate components.
Solution Approach 2:
The compensation coil serves multiple functions: it compensates for temperature drift, maintains the resonant frequency, and enables factor 1 detection across different metallic materials. This multi-functionality eliminates the need for separate temperature compensation devices or multiple independent coils.
2Reliability
If frequency measurement systems are used, then factor 1 detection is achieved, but cost increases and performance is limited
Solution Approach 1:
The patent replaces complex frequency measurement systems with a simpler amplitude-based detection method. By using a compensation coil to maintain stable resonant frequency, the system can rely on amplitude measurements alone, eliminating the need for expensive and complex frequency measurement circuitry while maintaining factor 1 detection accuracy.
3Reliability
If temperature compensation is implemented, then detection reliability is improved, but device complexity increases
Solution Approach 1:
Temperature compensation functionality is merged into the detection coil assembly itself through the compensation coil. The compensation coil is integrated with the detection coil in terms of spatial arrangement and electrical connection, eliminating the need for separate temperature compensation devices or additional sensing elements.
Solution Approach 2:
The compensation coil automatically compensates for temperature drift through its opposing winding configuration. As temperature changes affect both coils similarly, the compensation coil inherently counteracts the frequency shifts in the detection coil without requiring external control or additional compensation mechanisms.
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 configuration improves the detector's performance by stabilizing the signal, increasing the detection range, and reducing temperature-related variations, ensuring reliable and reproducible detection across different metallic materials.
Implementation Method 1
an LC resonant circuit supplied by an excitation pulse generator defining successive and repetitive phases of detection, means for acquiring and processing the response signal in the form of free oscillations delivered by said LC detection circuit
Implementation Method 2
a means for compensating the temperature drift of the response signal by correcting the sampled signal after its digital conversion, associated with or comprising a temperature sensor providing information on the temperature of at least a part of the detection device
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
The invention relates to a "factor 1" and inductive sensor device (1) comprising an LC resonant circuit (2) powered by a suitable generator (3), an operational chain of means (4, 5, 6) of acquisition by sampling and processing of the response signal, and a functional set of means (7, 8) of evaluating at least one temporarily set value of the processed signal and supplying detection or non-detection information. Said sensor device (1) is characterised in that the acquisition and processing means comprise analog means (5) for filtering and/or amplifying the sampled response signal, and a means (10) for compensating the temperature drift of the response signal by correcting the sampled signal following the digital conversion thereof, associated with or comprising a temperature sensor (10').