OSSD Signal Evaluation for Cabling Fault Detection
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Solution Overview
Problem
Current safety technologies face challenges in effectively monitoring OSSD output switching elements for errors in cabling, particularly when inputs of safe input devices are connected to OSSD outputs, as they cannot check wiring via their own test outputs and rely solely on OSSD output diagnostics, which is insufficient in cases like cross-circuits to 24V, leading to increased costs and security risks.
Innovation Solution
A method and device that separately record and evaluate static and dynamic signal components from OSSD output switching elements, using filter devices to distinguish between these components, allowing for cabling monitoring without special test pulses, and enabling cross-circuit detection through dynamic signal component analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If OSSD outputs are connected to input devices, then signal transmission is enabled, but cabling monitoring capability is lost
Solution Approach 1:
The patent introduces an intermediary evaluation device that mediates between the OSSD output switching element and the input device. This evaluation device receives signals from the OSSD output, separates static and dynamic components, and generates evaluation signals that enable cabling monitoring without requiring the input device to have its own test outputs connected to the OSSD outputs.
Solution Approach 2:
The patent implements a feedback mechanism where the evaluation device continuously monitors the signals from OSSD outputs, separates static and dynamic components, and provides evaluation information back to the system. This feedback enables ongoing cabling monitoring and fault detection, maintaining reliability while avoiding the complexity of direct test output connections.
2Device complexity
If OSSD outputs are used without separate test outputs, then device simplicity is maintained, but fault detection capability is insufficient
Solution Approach 1:
The patent segments the signal evaluation function into separate static component evaluation and dynamic component evaluation. The evaluation device separates the static signal components (representing the actual OSSD output state) from the dynamic signal components (representing test pulses and shutdown signals), allowing comprehensive fault detection without adding physical test outputs to the OSSD device.
Solution Approach 2:
The evaluation device acts as an intermediary that performs the fault detection function externally. Instead of embedding test output circuits within the OSSD device, the evaluation device provides the diagnostic capability through signal separation and evaluation, maintaining device simplicity while enhancing fault detection capability.
3Reliability
If shutdown pulses are filtered out at input devices, then safe operation is ensured, but cabling diagnostics are lost
Solution Approach 1:
The patent applies preliminary action by separating static and dynamic signal components at the evaluation device before the signals reach the input device. The dynamic components (including shutdown pulses used for diagnostics) are extracted and evaluated separately, allowing the input device to filter them out for safe operation while the evaluation device retains the diagnostic information for cabling monitoring.
Solution Approach 2:
The evaluation device provides feedback about the dynamic signal components that are being filtered out by the input device. This feedback mechanism ensures that while shutdown pulses are removed for safe operation, diagnostic information about cabling status is preserved and evaluated, preventing loss of diagnostic information.
Data Source
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AI summary
The method involves separating detection of static and dynamic signal components from signals coming from an output signal switching device-output switching element (100). The static signal components and the dynamic signal components are evaluated. An independent claim is included for a device for evaluating signals coming from an output signal switching device-output switching element.