Configurable Safety I/O Interface With Switch Fault Readback
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Solution Overview
Problem
Safety systems in safety technology face challenges in achieving fail-safe configurations, particularly at interfaces with external units, where short circuits can lead to malfunctions, necessitating a robust solution for reliable operation.
Innovation Solution
A safety system with a control and evaluation unit that includes a switching element, decoupling element, and level converters for functional testing, allowing for detection of defects like short circuits with minimal components and low design effort, ensuring flexible input/output configuration and continuous functional testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible interface with configurable input/output is implemented, then adaptability is improved, but reliability deteriorates due to potential short circuits and malfunctions
Solution Approach 1:
The patent implements preliminary functional testing of the switching element before it is put into operation. The control and evaluation unit performs self-tests by sending test signals through the switching element and evaluating the responses, detecting potential short circuits or malfunctions before they affect normal operation. This advance detection ensures reliable operation while maintaining interface flexibility.
2Reliability
If extensive functional testing components are added to detect defects, then reliability is improved, but device complexity increases
Solution Approach 1:
The control and evaluation unit serves multiple functions: it controls the switching element during normal operation, generates test signals for functional testing, evaluates the responses from the switching element, and detects defects. By making the control and evaluation unit multi-functional, the patent achieves comprehensive defect detection without adding separate dedicated testing components, thus avoiding increased device complexity.
Solution Approach 2:
The control and evaluation unit performs self-testing by internally generating test signals and evaluating its own switching element's response. The system tests itself without requiring external testing equipment or additional complex testing infrastructure, achieving reliable defect detection while maintaining simple device architecture.
3Reliability
If continuous functional testing is performed, then reliability is improved, but use of energy increases
Solution Approach 1:
The control and evaluation unit performs functional testing of the switching element at predetermined time intervals rather than continuously. This periodic testing approach maintains reliable defect detection capability while significantly reducing energy consumption compared to continuous monitoring, as the system alternates between normal operation and testing phases.
Data Source
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AI summary
The invention relates to a safety system (1) with at least one input/output (4), which is configurable as an input or output, and a control and evaluation unit (2) designed for evaluating and/or specifying signal states of the input/output (4). A switching element (8) controlled by the control and evaluation unit (2) is provided for specifying the configuration of the input/output (4). Furthermore, means for functional testing of the switching element (8) are provided, comprising a decoupling element (11) and a level converter (12) downstream of the decoupling element (11). When the switching element (8) is decoupled from the input/output (4) by the decoupling element (11), a defect in the switching element (8) can be detected by the fact that the output signal of the switching element (8) is read back into the control and evaluation unit (2) via the level converter (12) and evaluated there.