Fault Injection Circuit for Network Data Bus Diagnosis
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Solution Overview
Problem
Existing methods for diagnosing faults or open circuits in network data buses, such as those in vehicles, are impractical when cables are routed through conduits or structural elements, and existing solutions like voltage level detection are insufficient for all scenarios.
Innovation Solution
A system that injects a test signal with a logic level greater or lower than the normal levels into the network data bus, using a fault injection circuit and analog-to-digital converter to detect faulty connections by sensing the aggregate signal level, which exceeds the normal high or low logic levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If physical visual inspection of the transmission line is performed, then fault detection capability is improved, but accessibility and practicality deteriorate when cables are routed through conduits and structural elements
Solution Approach 1:
The patent replaces physical visual inspection with an electrical signal-based detection method. A test signal is injected into the network data bus through the fault injection circuit, and the detector monitors voltage levels to identify faults. This eliminates the need for physical access to cables routed through conduits and structural elements, as the electrical signals can traverse the same pathways used by normal network communication.
Solution Approach 2:
The patent introduces a fault injection circuit and detector as intermediary components that facilitate fault detection without requiring direct physical access to the transmission line. The fault injection circuit injects test signals into the data bus, and the detector analyzes the signal characteristics to identify faults, serving as a mediator between the diagnostic tool and the physical cable infrastructure.
2Difficulty of detecting and measuring
If voltage level detection is used to diagnose faults, then diagnostic capability is improved, but detection accuracy deteriorates in scenarios requiring access to routed cables
Solution Approach 1:
The patent employs parameter changes by injecting test signals with specific voltage levels that differ from normal network operation. The detector monitors for deviations in voltage levels caused by the injected test signals, allowing it to distinguish between normal operational variations and actual faults. This enables accurate fault detection without requiring physical access to routed cables.
Solution Approach 2:
The patent performs preliminary fault detection by injecting test signals before actual network communication occurs. The fault injection circuit introduces test signals into the data bus during a test time period, allowing the detector to identify potential faults before they interfere with normal network operation. This preliminary testing enables accurate diagnosis without disrupting ongoing communications.
3Measurement precision
If test signals with extreme logic levels are injected into the network data bus, then fault detection sensitivity is improved, but interference with normal network operation increases
Solution Approach 1:
The patent implements periodic action by injecting test signals only during designated test time periods when normal network communication is not occurring. The fault injection circuit is activated selectively to inject test signals, and the detector monitors during these specific intervals. This periodic testing allows for high-sensitivity fault detection while minimizing interference with ongoing network communications.
Solution Approach 2:
The patent performs preliminary fault detection by injecting test signals before actual network communication occurs. The fault injection circuit introduces test signals into the data bus during a test time period, allowing the detector to identify potential faults before they interfere with normal network operation. This preliminary testing enables accurate diagnosis without disrupting ongoing communications.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively diagnoses faulty connections in network data buses by identifying deviations in logic levels, enabling accurate fault detection even in inaccessible cable routes, improving diagnostic capabilities beyond traditional methods.
Implementation Method 1
The vehicle data bus communicates signals over a transmission line, such as one or more twisted pairs of wire or a coaxial cable
Implementation Method 2
a detector (e.g., voltage level detector) for sensing an aggregate level of an aggregate signal on the network data bus
Data Source
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AI summary
A fault injection circuit (34) injects a test signal into a data bus (17) with a normal high logic level and a normal low logic level. The test signal has a greater logic level greater than the normal high logic level of the data bus (17) or a lower logic level lower than the normal low logic level of the data bus (17). An analog-to- digital converter (36) is coupled to a voltage level detector (35) for sensing an aggregate level of an aggregate signal on the data bus (17). The aggregate signal is composed of the termination circuit signal and the test signal. A diagnostic tool (10) determines whether a faulty connection between the data bus (17) and a network device (44, 144, 244) exists, where the sensed aggregate level exceeds at least one of the normal high logic level and the normal low logic level.