CANopen Slave Node Standby Channel Switching
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Solution Overview
Problem
In CANopen-based train networks, slave nodes fail to communicate normally when their CAN channel faults occur in different networks, leading to operational disruptions and reduced redundancy effects.
Innovation Solution
The method involves switching to a standby CAN channel and transmitting an information forwarding request to the active master node to monitor and forward heartbeat packets and data, ensuring communication between nodes even when CAN channels of slave nodes are faulty.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all nodes transmit data over two lines simultaneously in CANopen-based redundancy network design, then network redundancy is improved, but device complexity and difficulty of detecting and measuring faults increase
Solution Approach 1:
The patent segments the network into active and standby sub-networks, with each node having separate CAN channels for each sub-network. This segmentation allows simplified configuration within each sub-network while maintaining overall redundancy, as nodes only need to follow simple rules for their respective active and standby channels rather than managing complex dual-line configurations simultaneously
Solution Approach 2:
The patent inverts the traditional redundancy approach by having nodes transmit data on only one active CAN channel at a time, rather than transmitting on both lines simultaneously. The standby channel remains inactive during normal operation and is activated only when the active channel fails, simplifying the operational complexity while maintaining redundancy benefits
2Ease of operation
If nodes receive data from only an active network by default, then ease of operation is improved, but reliability deteriorates when slave nodes are offline from the active network
Solution Approach 1:
The patent introduces the master node as an intermediary that receives data from slave nodes on the active network and forwards it to other slave nodes on the standby network. This intermediary mechanism enables indirect communication paths, maintaining reliability when direct active network paths are unavailable while keeping the system easy to operate through automated master node mediation
Solution Approach 2:
The patent establishes preliminary communication paths during network initialization, where the master node is pre-configured to monitor both active and standby networks and prepare forwarding mechanisms. This preliminary setup ensures that when faults occur, communication can immediately switch to alternative paths without requiring complex real-time decision-making, maintaining both ease of operation and reliability
3Reliability
If slave nodes switch to standby network when active network fails, then reliability is improved, but loss of time occurs during network switching
Solution Approach 1:
The patent implements preliminary monitoring of heartbeat packets on both active and standby networks, allowing nodes to detect failures and initiate switching procedures immediately. The master node is pre-configured with forwarding rules and alternative communication paths, enabling rapid switching without extensive reconfiguration, thus minimizing time loss while maintaining reliability
Solution Approach 2:
The patent employs heartbeat packet feedback mechanisms where slave nodes continuously monitor communication status and automatically trigger switching to standby networks when heartbeats are lost. This feedback-driven approach enables rapid, automated response to failures, reducing switching time while ensuring communication continuity through immediate failover
Data Source
AI summary
A CANopen-based train network data transmission method includes: switching, when a first CAN channel of a first slave node is detected as faulty, to a second CAN channel of the first slave node to receive over a standby network a heartbeat packet and data transmitted by another relevant node; monitoring, if no heartbeat packet transmitted by a relevant second slave node is received from the standby network within a preset heartbeat period, by an active master node, in an active network, a heartbeat packet and data transmitted by the second slave node; receiving, through the second CAN channel, the heartbeat packet and the data of the second slave node forwarded by the active master node to the standby network when the active master node detects in the active network the heartbeat packet and the data transmitted by the second slave node through the first CAN channel.