Encoder Signal Monitoring via Peak-Hold Vector Length
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Solution Overview
Problem
Existing encoder systems face limitations in reliability and cost-effectiveness, particularly in safety-critical applications where redundancy and diversity are required, leading to complex and expensive systems, and conventional monitoring methods struggle with detecting temporary signal deviations due to high digitization and evaluation rate demands.
Innovation Solution
The use of a peak value holding device to monitor and store extreme values of sine and cosine signals, allowing for reliable monitoring without the need for additional redundancy and independent signal paths, enabling cost-effective production and flexible application beyond motor feedback systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundancy and diversity are used to meet safety requirements, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines the safety monitoring function with the existing encoder system by using the same signal lines for both position feedback and safety monitoring. The sine and cosine signals are evaluated for safety purposes directly from the encoder output without requiring separate redundant sensor systems, thereby merging multiple functions into a single integrated system.
Solution Approach 2:
The encoder signal lines serve dual purposes: providing position feedback to the drive system and enabling safety monitoring through vector length evaluation. This multi-functional use of existing components eliminates the need for dedicated redundant safety systems while maintaining safety integrity.
2Measurement precision
If digitization and evaluation rate are increased to detect temporary signal deviations, then measurement precision is improved, but use of energy and processing requirements increase
Solution Approach 1:
The patent replaces complex high-speed digitization and processing systems with an analog evaluation method. The vector length is calculated directly from the analog sine and cosine signals using simple arithmetic operations (squaring, adding, square root), avoiding the need for high-speed analog-to-digital conversion and intensive digital processing while maintaining detection precision.
Data Source
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AI summary
The device (10) has measuring unit (22) that is connected with first object and a sampling unit (24) which is connected to second object for generating a first signal and a second signal in dependence on the position of a scanning of the measuring unit. A monitoring unit (30) detects malfunction of the device based on the first signal and the second signal. The monitoring unit has peak-hold unit (32) for storing an extreme value of the first signal and/or the second signal. An independent claim is included for method for determining position of first object relative to movable second object.