Train Communication Architecture Segregating SIL 0 and SIL 1-2 Data Processing
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Solution Overview
Problem
The existing train communication network architectures face significant challenges in reducing the time and cost associated with validation and certification of safety functions, particularly for higher Safety Integrity Levels (SIL) due to complex and costly processes.
Innovation Solution
A communication network architecture that segregates data processing using a central processing unit for SIL 0 data and a coprocessor for SIL 1 and SIL 2 data, employing a 'black channel' technique to transmit safety-level data, where the coprocessor handles validation and encoding, reducing the complexity and cost of development and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate processors are used for SIL 0 and SIL 1-2 data with separate communication channels, then safety validation and certification are improved, but device complexity and cost increase
Solution Approach 1:
The patent divides the communication network into two distinct segments: a first network for transmitting SIL 0 data and a second network for transmitting SIL 1-2 data. This segmentation allows each network to be validated and certified according to its specific safety requirements, with the second network requiring higher safety standards. By separating the networks at the protocol and transmission levels rather than requiring separate processors, the patent achieves safety segmentation while reducing overall system complexity.
2Reliability
If separate processors are used for SIL 0 and SIL 1-2 data with separate communication channels, then safety validation and certification are improved, but development and maintenance costs increase
Solution Approach 1:
The patent merges the processing functions into a single processor that handles both SIL 0 and SIL 1-2 data, while maintaining separate communication networks for transmission. This merging approach reduces the number of processors required, thereby lowering development, validation, and maintenance costs associated with multiple processors. The single processor can be validated once, and the safety-critical aspect is shifted to the network transmission layer, which can be independently validated.
3Device complexity
If a single processor handles both SIL 0 and SIL 1-2 data, then device complexity and cost are reduced, but safety validation and certification become more difficult
Solution Approach 1:
The patent applies different quality standards to different parts of the system. The communication network for SIL 1-2 data is designed with higher safety requirements (separate network, protocol validation, error checking) while the SIL 0 network uses standard protocols. This local differentiation of quality standards allows the system to meet high safety requirements for critical data without requiring the entire system to be validated to the same level, thus reducing overall validation complexity.
Data Source
AI summary
A communication architecture of a train in which at least one central processing unit arranged in a train carriage is interconnected through a communication network of the train with a plurality of peripheral processing units. The central processing unit is provided on a single board with: a processor designed to process data associated with an SIL 0 safety level; a coprocessor designed to process data associated with an SIL 1-SIL 2 safety level; an internal bus built on the board and configured to allow a two-way data communication between the processor and the coprocessor; an interface for the communication network of the train. The coprocessor is designed to be programmed in a reconfigurable manner with a software that allows the validation and encoding of data coming from the processor according to a safety protocol.