Weighing Cell Self-Diagnosis via Coil Deflection and Current
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Solution Overview
Problem
Force-measuring devices, particularly those using electromagnetic force compensation, face challenges in detecting damage to flexure pivots or position changes within the coil and magnet system, leading to inaccurate weighing results without visible impairment, requiring periodic manufacturer-led inspections for verification.
Innovation Solution
A method involving a processor unit that compares system-characterizing means with stored system reference means, utilizing the magnitude of electric current and coil deflection to verify functionality, allowing for self-diagnosis and maintenance scheduling at the device's location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If periodic manufacturer-led inspections are conducted to verify device functionality, then measurement accuracy is maintained, but device downtime and operational costs increase
Solution Approach 1:
The weighing device performs self-diagnosis by automatically comparing current system-characterizing means (coil deflection, electric current magnitude) with stored reference means to detect damage to flexure pivots or position changes, eliminating the need for periodic manufacturer inspections and reducing device downtime while maintaining measurement accuracy
2Measurement precision
If flexure pivots are made thinner to achieve high resolution, then measurement precision improves, but susceptibility to damage increases
Solution Approach 1:
The system continuously monitors system-characterizing means including coil deflection and electric current magnitude, providing feedback to detect when thin flexure pivots become damaged due to excessive stress, allowing early intervention before complete failure occurs and maintaining both high resolution and reliability
3Productivity
If on-site self-diagnosis is implemented, then verification costs and downtime are reduced, but device complexity increases
Solution Approach 1:
The processor unit performs multiple functions including normal weighing operations and self-diagnosis by comparing system-characterizing means with reference means, allowing the same hardware to serve dual purposes without significantly increasing device complexity while improving operational efficiency
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 on-site verification of force-measuring device functionality, reducing downtime and costs by detecting potential damage and maintaining accuracy through self-diagnosis and proactive maintenance.
Implementation Method 1
the weight force of the weighing object is transmitted to an electromechanical measurement transducer... The measurement transducer produces a compensating force corresponding to the weight force of the weighing object
Implementation Method 2
an electric current flows through the coil, whereby a compensating force is generated which counteracts the load place on the balance
Data Source
AI summary
A force-measuring device (1) with a parallelogram linkage has a measurement transducer coupled to it. A coil (25) of the transducer has guided mobility in a magnet system (27) and can carry an electric current (24). A position sensor (21) detects the deflection of the coil (25) from a balanced position relative to the magnet system when a load is placed on the force-measuring device. The electric current (24) flowing through the coil (25), by way of the interaction between the coil and the magnet system, returns the coil and the movable parallel leg to the balanced position. A system-characterizing means (29) is established in a processor unit (26). The system-characterizing means and an unchangeable system reference means (30) are compared to determine the functionality of the device. The functionality is verified by the magnitudes of the electric current and the deflection of the coil from its balanced position.