Sensor Amplifier Gain Switching for Multi-Detector Material Testing

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Solution Overview

Problem

Existing material testing machines face challenges in using amplifiers optimally across different displacement meter types and sensitivity levels, leading to insufficient resolution and calibration issues, particularly when switching between displacement meters and load cells.

Innovation Solution

A measuring device with a cable unit containing a nonvolatile memory and a resistor that adjusts the gain of the instrumentation amplifier based on detector information, along with an electrical calibration circuit, allows for automatic gain adjustment and calibration regardless of detector type or sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single amplifier device is used for multiple detector types, then device complexity is reduced, but measurement precision deteriorates due to sensitivity differences

Engineering Contradiction:
Improveamplifier device complexityVSAvoidmeasurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by automatically adjusting the gain parameter of the amplifier based on the connected detector type. The system detects whether a load cell or displacement meter is connected and dynamically changes the amplifier gain to optimize measurement precision for each detector type, resolving the contradiction between using a single amplifier device and maintaining measurement precision.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If gain is adjusted with digital circuit after ADC, then ease of operation is improved, but measurement precision deteriorates due to insufficient resolution

Engineering Contradiction:
Improvegain adjustment easeVSAvoidresolution
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent implements preliminary action by adjusting the amplifier gain before the ADC conversion process. The gain is automatically set according to the detector type prior to signal conversion, ensuring that the full scale of the ADC converter is sufficiently utilized and resolution is maximized, while still maintaining ease of operation through automated control.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If amplifier gain is optimized for high-sensitivity detectors, then measurement precision is improved, but productivity deteriorates due to calibration requirements

Engineering Contradiction:
Improvemeasurement precisionVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent applies self-service by implementing automatic gain adjustment that eliminates the need for manual calibration operations. The system automatically detects the detector type and configures the appropriate gain setting without requiring user intervention or calibration procedures, thereby maintaining measurement precision while significantly improving productivity by eliminating calibration time.

Inventive Principle:
Principle #25Self-service

4Adaptability or versatility

If a universal amplifier device is designed, then adaptability is improved, but measurement precision deteriorates for specific detector types

Engineering Contradiction:
Improvedetector compatibilityVSAvoiddetector-specific precision
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent implements dynamics by making the amplifier gain adjustable and adaptive based on the connected detector type. Rather than designing separate amplifiers for each detector type, the system dynamically changes the gain parameter to match the specific detector characteristics, achieving both universal adaptability and detector-specific measurement precision through a single flexible device.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3421966B1Measurement device and material tester
Publication Date: 2020.11.25 SHIMADZU CORP
  • EP3421966B1 patent drawingFigure 1
  • EP3421966B1 patent drawingFigure 2
  • EP3421966B1 patent drawingFigure 3(a)~3(c)

AI summary

Once a sensor amplifier side connector of a cable unit 24 for interconnecting a detector and a sensor amplifier 42 is connected to the sensor amplifier 42, a gain resistor 26 on the cable unit 24 side and an instrumentation amplifier 56 of the sensor amplifier 42 are interconnected and the gain of the instrumentation amplifier 56 is determined. As a result, the gain of the instrumentation amplifier 56 is determined such that the magnitude of a signal that the sensor amplifier 42 receives from the detector becomes a magnitude optimal for an analog circuit in the sensor amplifier 42.