Electronic Interlocking FPGA Logic Circuit Replacement
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Solution Overview
Problem
Existing relay interlockings for railway traffic are costly to maintain and replace due to their complex software-based electronic interlocking systems, which require significant certification efforts and investments, and are prone to errors that can compromise safety.
Innovation Solution
Replacing relay interlockings with a functionally equivalent electronic circuit using semiconductor modules, such as Field Programmable Gate Arrays (FPGAs), which configures hardware logic structures to replicate the switching logic of relay circuits, reducing the need for software implementation and minimizing changes to outdoor systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If relay interlockings are replaced by software-based electronic interlockings, then modern technology and automation are achieved, but certification effort and project costs increase significantly
Solution Approach 1:
The patent replaces the software-based control system with a hardware-based field programmable gate array (FPGA) that implements the interlocking logic through configurable logic circuits. This substitution eliminates the need for complex software certification while maintaining automation, as the FPGA's hardware implementation provides deterministic and verifiable behavior without the complexities of software execution paths and state management.
Solution Approach 2:
The patent changes the fundamental parameter of implementation from software to hardware (FPGA). By configuring the FPGA with the interlocking logic during manufacturing or deployment, the system achieves automation with simplified certification, as hardware logic can be verified through circuit analysis and testing rather than software code review and validation.
2Extent of automation
If relay interlockings are replaced by software-based electronic interlockings, then modern technology is achieved, but maintenance and operating costs increase
Solution Approach 1:
The patent replaces software-based control with hardware-based FPGA implementation. This substitution improves ease of repair and reduces maintenance costs because FPGA devices are inherently more reliable than software systems, with no moving parts, no software bugs, and deterministic behavior. The hardware implementation eliminates the need for software updates, patches, and complex debugging procedures.
3Extent of automation
If relay interlockings are replaced by software-based electronic interlockings, then automation is achieved, but integration with remote control systems becomes costly
Solution Approach 1:
The patent implements the interlocking logic in an FPGA, which provides universal interfaces and communication capabilities that can integrate with various remote control and automation systems. The FPGA can be configured to support multiple communication protocols and interface types, reducing integration costs and simplifying connectivity with external systems compared to proprietary software solutions.
4Extent of automation
If central computer systems with complex software are used for electronic interlocking, then automation is achieved, but errors can compromise safety
Solution Approach 1:
The patent replaces software-based control with hardware-based FPGA implementation to improve safety and reliability. The hardware logic provides deterministic behavior without software bugs, race conditions, or execution errors. The configurable logic circuits in the FPGA ensure that safety-critical interlocking functions are implemented with high reliability, eliminating the risk of software-induced safety compromises.
Data Source
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AI summary
According to one aspect of the invention, the circuit logic of an existing relay interlocking system is mapped onto a functionally equivalent circuit of electronic components. Semiconductor components that are functionally identical to the components of the relay circuit are thus preferably used. The circuit logic is created, for example, by transforming an interlocking table or track diagram into a logic circuit by means of an automatic compiler according to predefined rules.