Position Encoder Signal Switching for ADC Fault Tolerance

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Solution Overview

Problem

Existing devices for determining relative position are prone to errors due to issues like stuck-at-fault errors or bit flips in analog-to-digital converters, especially in configurations requiring fine resolution, leading to significant inaccuracies.

Innovation Solution

Incorporating a signal exchanger that varies the distribution of measurement signals to different outputs, allowing errors to be minimized, identified, and compensated for, and providing an evaluation unit to detect and correct faults.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed assignment of sensors to analog-to-digital converters is used, then the device structure is simple, but errors in ADCs cause significant and permanent measurement inaccuracies

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidsignal distribution structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic signal distribution by repeatedly varying the assignment of measurement signals from sensors to analog-to-digital converters. Instead of a fixed connection, the system dynamically changes which ADC processes which sensor signal over time, allowing error detection and compensation while maintaining system functionality.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The evaluation and control unit acts as an intermediary that coordinates the signal exchanger and manages the dynamic reassignment of signals. This intermediary component orchestrates the variation in signal distribution and handles the complexity of tracking and compensating for ADC errors, separating the complexity from the core measurement function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If signal distribution is repeatedly varied, then errors can be detected and compensated, but the processing complexity increases

Engineering Contradiction:
Improvefault detection capabilityVSAvoidsignal exchanger control
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system employs feedback mechanisms where the evaluation and control unit monitors the measurement signals and uses this information to control the signal exchanger's reassignment pattern. The feedback loop enables the system to adaptively manage signal distribution based on detected errors, improving fault detection while managing processing complexity through intelligent control.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-diagnosis and self-correction by automatically detecting ADC errors through the varied signal distribution and compensating for them without external intervention. The evaluation unit autonomously manages the error detection and compensation processes, reducing the need for external error handling mechanisms.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4597040B1Device and method for determining position, length or angle
Publication Date: 2026.03.04 SICK AG
  • EP4597040B1 patent drawingFigure 1
  • EP4597040B1 patent drawingFigure 2A
  • EP4597040B1 patent drawingFigure 2B

AI summary

The present invention relates to a device for determining position, length, or angle, comprising a first and a second part which are movable relative to one another. A code with a plurality of code sections of a first and second type is attached to the first part. A readout device for detecting at least part of the code is attached to the second part, wherein the readout device comprises at least two sensors, each designed to detect the individual code sections and to output a corresponding analog measurement signal. Furthermore, at least two analog-to-digital converters are provided, which are at least indirectly connected to the provided sensors and designed to digitize and output the measurement signals. A further evaluation and control unit is designed to determine a relative position between the first and second parts from the digitized measurement signals.At least one signal exchanger is provided between the sensors and the analog-to-digital converters. This signal exchanger is designed to repeatedly vary the distribution of the incoming measurement signals from the individual sensors to different outputs of the signal exchanger. Furthermore, the present invention relates to a corresponding method.