Traction vehicle distributed control computer system architecture with auto reconfiguration features and extended DMA support

The system design principles and hardware and software architecture of the distributed network control computer (DNCC) of a traction vehicle are presented. The system design is based on such criteria as functionality, reliability and maintainability. The number of computer network node types is minimized. Network node scans its physical position inside the network and automatically reconfigures itself to the required function using correct software to configure FPGA based hardware parts and to run correct control algorithms on the host processors. To get these properties special emphasis is placed on correct and optimal system function partition among distributed computer nodes to minimize the overall communication overhead and to minimize the hardware parts of the system and to move maximum of functions into the software. As an example of such design task the DNCC of an electric locomotive is presented. The vehicle DNCC is organized as a local computer network with master-slave node access method with the dual serial bus. The network communication services are uniformly used in all nodes to support reliable transfer of the process data. The communication overhead is minimized using exclusively DMA transfer method. DMA support is utilized to be the time information captured precisely (averaging ADCs) too. User task in the DNCC nodes are scheduled by the preemptive real time operation system with dynamic planning or by the simple static executive in the nodes with extra high requirements on the fast interrupt response.