Short-Circuit Signaling Element State Detection via Alternating Logic Signals
Solution Overview
Problem
Existing methods for detecting the actuation of short-circuit-forming signaling elements are limited by the frequency of blanking intervals, leading to potential undetection of brief actuations and requiring precise knowledge of signal timing, which compromises detection accuracy and safety.
Innovation Solution
Applying opposite logic signals to the current paths of a short-circuit-forming signaling element, allowing for an either/or evaluation that is independent of wiring and timing, enabling immediate detection of actuation and cross-circuit errors through a simple and reliable method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If blanking intervals are used to detect actuation of short-circuit-forming signaling elements, then the detection method is simple and can identify cross-circuits, but the detection accuracy is limited by the frequency of blanking intervals and brief actuations may be missed
Solution Approach 1:
The patent applies periodic action by using alternating logic signals (0 and 1) that are continuously switched at a high frequency to the two current paths. This periodic signal application enables the detection system to capture even very brief actuations, as the high-frequency alternation ensures that the actuation state will be sampled during its duration. The periodic nature of the signal also allows for continuous monitoring without missing transient events.
Solution Approach 2:
The patent changes the parameter of logic signal assignment by periodically swapping which current path receives logic 0 and which receives logic 1. This parameter change approach allows the system to detect actuations regardless of which specific path is actuated, and the high-frequency parameter switching enables detection of brief actuations that would occur between slower blanking intervals. The evaluation logic detects when both paths show the same logic value, indicating actuation.
2Reliability
If blanking intervals with offset timing are used to detect short-circuit-forming elements, then cross-circuits can be detected, but the system requires precise knowledge of signal timing positions
Solution Approach 1:
The patent inverts the traditional blanking interval approach by instead applying continuous alternating logic signals to both current paths. Rather than using periods of no signal (blanking) to detect actuation, the system uses the presence of alternating signals and detects when both paths simultaneously show the same logic value. This inversion eliminates the need for precise timing synchronization while maintaining cross-circuit detection capability, as the high-frequency alternation ensures sampling occurs during any actuation event.
Solution Approach 2:
The patent implements continuity of useful action by continuously applying logic signals to both current paths without interruption or blanking intervals. The signals alternate continuously between logic 0 and logic 1, ensuring that the detection function operates without gaps. This continuous action eliminates the timing synchronization requirements of blanking interval methods, as there are no discrete timing events that need to be precisely coordinated between different signal paths.
3Measurement precision
If high-frequency blanking intervals are used to improve detection accuracy, then brief actuations can be detected, but the system complexity and timing precision requirements increase
Solution Approach 1:
The patent merges the detection of both current paths into a single evaluation logic that simultaneously monitors the logic states of both paths. By combining the monitoring function and using an either/or evaluation (detecting when both paths show the same logic value), the system achieves high detection accuracy for brief actuations without requiring separate timing synchronization systems for each path. The merged evaluation approach simplifies the overall system architecture while maintaining high precision.
Data Source
Figure 1~2
Figure 3
AI summary
A method for determining the switching state of a short-circuit-detecting signaling element (20) with a first current path (22) and a second current path (24), wherein a safety controller (1) injects a first logic signal into an input (26) of the first current path (22) and a second logic signal into an input (26) of the second current path (24), and the logic signals at the outputs (28) of the current paths (22, 24) are read by the safety controller (1). For this purpose, at a given time, the first injected logic signal corresponds to a 0 and the second injected logic signal to a 1, and the state of the signaling element (20) is determined by the safety controller (1) by means of an either/or evaluation of the read logic signals.