Dual Hall Sensor Feedback for Magnet Failure Diagnosis

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Solution Overview

Problem

Existing digital level controllers with single Hall-effect sensors face challenges in diagnosing malfunctions, as it is difficult to determine whether the sensor, magnet, or other components have failed, especially in inaccessible locations, leading to unclear failure modes and practical difficulties in visual inspection.

Innovation Solution

A system utilizing two magnetic field sensors and a processor to generate diagnostic information by comparing their output signals, allowing for the determination of specific failure modes, such as magnet or sensor failures, through monitoring the relationship between the signals, and providing feedback for process control devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single Hall-effect sensor is used to detect magnet movement, then the device complexity is reduced, but the ability to diagnose sensor or magnet failures is lost

Engineering Contradiction:
Improvenumber of sensorsVSAvoidfailure diagnosis capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements feedback by having multiple magnetic field sensors continuously monitor the magnetic field and compare their readings. The system expects a specific relationship between sensor outputs and can detect when this relationship deviates, indicating a failure in the magnet, sensor, or feedback mechanism. This feedback loop enables real-time diagnosis without increasing overall system complexity significantly.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent uses the magnetic field itself as an intermediary to transfer information between the magnet and multiple sensors. By monitoring changes in this intermediary (the magnetic field) from multiple sensing points, the system can diagnose failures in either the magnet or the sensors themselves, resolving the contradiction between simplicity and diagnostic capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple magnetic field sensors are used to enable failure diagnosis, then the reliability is improved, but the device complexity increases

Engineering Contradiction:
Improvefailure diagnosis capabilityVSAvoidnumber of sensors
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The multiple magnetic field sensors serve multiple functions: they simultaneously provide position feedback for process control and enable failure diagnosis through comparative analysis. This multi-functionality justifies the increased device complexity by extracting maximum utility from each additional sensor, addressing both control and reliability needs.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses feedback from multiple sensors to continuously monitor the relationship between their outputs. When this relationship deviates from expected patterns, the system can diagnose specific failure modes (magnet failure, sensor failure, feedback failure). This feedback mechanism enables reliable failure diagnosis while keeping the complexity manageable through intelligent signal processing.

Inventive Principle:
Principle #23Feedback

3Device complexity

If visual inspection is used to diagnose sensor or magnet failures, then the device complexity is low, but the ease of operation deteriorates due to inaccessible locations

Engineering Contradiction:
Improvediagnosis method simplicityVSAvoidinspection accessibility
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The system performs self-diagnosis by automatically monitoring its own components through multiple magnetic field sensors. The sensors continuously assess the health of the magnet and each other, eliminating the need for manual visual inspection. This self-service capability allows the system to diagnose failures remotely and automatically, resolving the contradiction between simple diagnosis methods and accessibility to inaccessible components.

Inventive Principle:
Principle #25Self-service

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

Enables effective failure detection and diagnosis, including mechanical or electrical failures, by analyzing the relationship between output signals from multiple sensors, thereby improving the reliability and maintenance of digital level controllers.

Implementation Method 1

Movement of one or more of the magnets alters a magnetic field measured at a Hall-effect sensor, which causes the Hall-effect sensor to provide an output signal

Methodology Applied
Scientific EffectHall effect: Hall Effect

Data Source

PatentEP3172531B1Magnetic field sensor feedback for diagnostics
Publication Date: 2020.11.04 FISHER CONTROLS INT LLC
  • EP3172531B1 patent drawingFigure 1
  • EP3172531B1 patent drawingFigure 2
  • EP3172531B1 patent drawingFigure 3~4

AI summary

Magnetic field sensor feedback for diagnostics is disclosed herein. A disclosed example apparatus includes a first magnetic field sensor to provide a first output signal in response to a magnetic field generated by a magnet coupled to a movable portion of a process control device, and a second magnetic field sensor to provide a second output signal in response to the magnetic field. The disclosed example apparatus also includes a processor to use the first and second output signals to generate diagnostic information associated with a feedback of the process control device.