CAN Bus Node Diagnosis Module for Real-Time Signal Analysis
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Solution Overview
Problem
Current methods for analyzing the health of the CAN bus physical layer are not economically viable or reliable for real-time monitoring, especially in operational environments, and fail to detect issues like open, shorted, or unbalanced lines effectively.
Innovation Solution
A node and transceiver system with a diagnosis module that performs measurements and signal analyses on a CAN bus using a carrier sense multiple access/collision detection mechanism, allowing for real-time monitoring by asserting an enable signal during exclusive access phases to ensure accurate signal analysis without interference from multiple nodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard equipment such as voltmeters and standard oscilloscopes is used to analyze the signaling on a CAN bus, then measurement capability is provided, but the system is not economically viable or reliable for real-time monitoring in operational environments
Solution Approach 1:
The node performs self-diagnosis by using its own transceiver and protocol engine to monitor the CAN bus signals. The diagnosis module within the node itself conducts measurements and signal analyses, eliminating the need for external standard equipment and enabling reliable real-time monitoring in operational environments.
Solution Approach 2:
The transceiver is configured to perform multiple functions: normal CAN bus communication and simultaneous diagnosis/monitoring of the bus signals. This multi-functionality allows the same hardware to serve both communication and measurement purposes, making the system economically viable and reliable for real-time monitoring.
2Productivity
If measurements are conducted on a multi-master bus where multiple nodes can access simultaneously, then continuous monitoring is possible, but signal analysis accuracy is compromised due to interference from multiple nodes
Solution Approach 1:
The protocol engine is configured to transition to a specific state indicative of an exclusive access phase before measurements are conducted. This preliminary state transition ensures that only one node is active on the bus when the diagnosis module performs its measurements, guaranteeing signal analysis accuracy while maintaining continuous monitoring capability through the multi-master protocol.
3Reliability
If the node continuously monitors the CAN bus signals, then real-time detection of issues is achieved, but the complexity of the node increases
Solution Approach 1:
The diagnosis module is integrated within the existing node structure, merging the monitoring function with the node's existing transceiver and protocol engine. This integration allows real-time issue detection without significantly increasing node complexity, as the same hardware components are reused for both communication and diagnosis purposes.
Data Source
AI summary
The present application relates to a node for conducting measurements and signal analyses on a bus supporting multi-master access of a plurality of nodes or a transceiver of the node. The transceiver is configured to detect bus signals and to convert the detected bus signals into a bit stream. A protocol engine is arranged to receive the bit stream. The protocol engine transitions between states, which are indicative of at least an exclusive access phase, during which only one of the plurality of nodes is allowed to assert signals on the bus. A detector is configured to assert an enable indication for a period of time on detecting that the protocol engine is in a state indicative of the exclusive access phase. A diagnosis module is configured to conduct measurements in response to the asserted enable indication.