Position Encoder Readout with Limited-Range ADC Digitization

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Solution Overview

Problem

Conventional devices for determining position, length, or angle are time-consuming and limited in resolution due to the comprehensive comparison of measurement signals with a full set of reference values across their entire amplitude range.

Innovation Solution

A specification unit generates a specification signal that defines a range of reference values for subsequent digitization, allowing the analog-to-digital converter to digitize the measurement signal within this limited range, thereby reducing the number of comparisons needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If comprehensive comparison of measurement signal with full set of reference values is performed, then measurement precision is improved, but time required for digitization increases

Engineering Contradiction:
Improveresolution of relative positionVSAvoidtime required for digitization
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The specification unit performs preliminary determination of the range of reference values based on the previous measurement value before the actual digitization process. This preliminary action identifies which reference values are relevant for the current measurement, allowing the analog-to-digital converter to focus only on those specific reference values rather than comparing against the entire set, thus reducing digitization time while maintaining precision

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of using a uniform set of reference values across the entire amplitude range, the invention applies local quality by selecting only the specific subset of reference values that are relevant for the current measurement range. The specification unit determines the appropriate range based on the previous measurement, and the analog-to-digital converter uses only those local reference values, making the digitization process more efficient and targeted

Inventive Principle:
Principle #3Local quality

2Measurement precision

If comprehensive comparison of measurement signal with full set of reference values is performed, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveresolution of relative positionVSAvoidcomplexity of digitization process
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The digitization process is segmented into two functional parts: the specification unit that determines the range of reference values based on previous measurements, and the analog-to-digital converter that performs digitization using only the specified subset of reference values. This segmentation divides the complex task of comprehensive comparison into a simpler process of range determination followed by targeted digitization, reducing overall device complexity

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4597041B1Device and method for determining position, length or angle
Publication Date: 2025.12.31 SICK AG
  • EP4597041B1 patent drawingFigure 1
  • EP4597041B1 patent drawingFigure 2

AI summary

The present invention relates to a device for determining position, length, or angle, comprising a first part with a coding and a second part with a readout device, as well as at least one analog-to-digital converter and an evaluation unit for determining the relative position between the first and second parts. Furthermore, a specification unit is provided and configured to generate a specification signal, based on a previously measured output value of the measurement signal to be digitized, which indicates a range of reference values to be used for the subsequent digitization of the measurement signal, and to output it to the analog-to-digital converter.The analog-to-digital converter is designed to digitize the at least one measurement signal, at least in a first step, in particular completely, solely based on reference values that lie between a lower limit and an upper limit of the range for reference values to be used for the subsequent digitization of the measurement signal. The present invention also relates to a corresponding method.