Analog Sensor Digital Compensation Interface

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Solution Overview

Problem

Traditional strain-gauge type analog weighing sensors have complex interfaces due to the need for specific digital ports to output compensated weight data, limiting connectivity with measuring instruments and peripherals, and struggle with accuracy in compensating for errors like creep and delay.

Innovation Solution

An analog weighing sensor with a digital compensation function that includes an analog-to-digital conversion module, a signal processing and output circuit with a compensation module, and a digital-to-analog conversion module, which simplifies interfaces while achieving high-accuracy compensation by converting analog signals to digital and back, addressing errors through operational amplification and pulse width modulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If digital compensation is implemented using specific digital ports to output compensated weight data, then measurement precision is improved, but device complexity increases and adaptability decreases

Engineering Contradiction:
Improvecompensation accuracyVSAvoidinterface complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a digital signal processing unit as an intermediary component that receives analog signals from the strain gauge bridge, performs digital compensation calculations, and outputs corrected digital signals. This mediator handles the complex compensation algorithms internally, allowing the analog sensor to maintain simple external analog interfaces while achieving high-precision digital compensation through the intermediate processing stage.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent makes the analog output port multi-functional by enabling it to output both traditional analog signals and compensated weight data through the same physical interface. The digital compensation unit processes signals internally and can output corrected data through the existing analog port or digital interfaces, eliminating the need for separate dedicated digital output ports and enhancing interface universality.

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

2Measurement precision

If digital compensation is implemented through specific digital ports, then measurement precision is improved, but adaptability to different measuring instruments and peripherals decreases

Engineering Contradiction:
Improvecompensation accuracyVSAvoidconnectivity compatibility
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent enhances adaptability by designing the signal processing unit to provide multiple output options including both analog and digital interfaces. The system can output compensated data through standard analog ports that are universally compatible with measuring instruments, while also providing digital output capabilities through common protocols like RS232/485 or CANOPEN, thereby maintaining broad connectivity compatibility while achieving high-precision compensation.

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

3Device complexity

If traditional analog compensation methods are used with resistors in series or parallel, then device complexity is kept low, but measurement precision and ability to address time-related errors deteriorates

Engineering Contradiction:
Improvecompensation circuit simplicityVSAvoidcompensation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces traditional mechanical/analog resistor-based compensation circuits with a digital signal processing approach. Instead of using physical resistors connected in series or parallel with the strain gauge bridge, the system uses a digital processing unit that receives analog signals, converts them to digital form, applies compensation algorithms, and outputs corrected signals. This substitution maintains relative simplicity while dramatically improving compensation accuracy and the ability to address time-related errors like creep and delay.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter of compensation from analog resistance adjustments to digital signal processing. By converting the compensation mechanism from physical component adjustments to digital algorithmic processing, the system achieves higher precision while maintaining manageable complexity through software-based parameter adjustment and correction.

Inventive Principle:
Principle #35Parameter changes

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

The solution provides simple interfaces for analog weighing sensors while achieving high-accuracy compensation, effectively addressing errors related to creep and delay, and enhancing connectivity with measuring instruments and peripherals.

Implementation Method 1

at least one strain gauge connected to the deformation part and generating a change in the resistance according to the deformation

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Implementation Method 2

at least one strain gauge bridge connected to the at least one strain gauge and transferring the change in the resistance of the at least one strain gauge to output a first analog signal

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3063514B1Analog sensor with digital compensation function
Publication Date: 2019.05.08 METTLER TOLEDO (CHANGZHOU) PRECISION INSTR CO LTD
  • EP3063514B1 patent drawingFigure 1
  • EP3063514B1 patent drawingFigure 2
  • EP3063514B1 patent drawingFigure 3

AI summary

An analog sensor (100, 500, 600, 700, 800, 900) with digital compensation function comprises: a deformation part (102) generating a deformation according to a pressure sensed by the analog sensor (100, 500, 600, 700, 800, 900), a strain gauge (104) connected to the deformation part (102) and generating a change in the resistance according to the deformation, a strain gauge bridge (106) connected to the strain gauge (104) and transferring the change in the resistance of the at least one strain gauge (104) to output a first analog signal, an analog-to-digital conversion module (108, 508, 708, 808, 908) connected to an output of the strain gauge bridge (106), receiving the first analog signal from the strain gauge bridge (106) and converting the first analog signal to a first digital signal, where the first analog signal is an analog signal representative of weight, an analog output port (116) for outputting a second analog signal, and a signal processing and output circuit (110, 510, 610, 710, 810, 910) connected between the output of the analog-to-digital conversion module (108) and the analog output port(116), compensating and converting the first digital signal into the second analog signal. The analog sensor (100, 500, 600, 700, 800, 900) may achieve high-accuracy compensation while keeping the interfaces of the analog weighing sensor to be simple.