Design And Practice Of The Bi-processor Railway Axis-counting System On The Base Of CAN Bus

With the rapid economic development of our country, it is urgent that for the computer-controlled axis-counting systems to be used in railway regions. The nationalization of it will not only improve the availability of railway regions, but also save a lot of foreign exchanges. Based on the features of Safety First in railway systems, it has profound significance to have a reliability design to axis-counting systems. There are two designing cases for reliability: they are fault avoiding and fault-tolerance. Fault-tolerance will improve reliability from system structure. It is a feasible plan of reliable systems design facing application.Therefore, to use fault-tolerance technology to design the railway, axis-counting system has become a valid means of improving the reliability of computer systems. As the subject to design fault-tolerance computer axis-counting system systematically and realized it, CAN bus is used in the system design, which is the first at home. Meanwhile the original ideas in the system structure, principle and realization has been put forward .It is an improved fault-tolerance technology.The paper makes an analysis of the needs of the fault-tolerance design, suggesting the reliability requirements in the railway axis-counting computer and positioned the fault-tolerance category. After that fault pattern and effect analysis have been applied to make an analysis to the hardware and get a conclusion that the master and A/D needs fault-tolerance design.On the design stage, an axis-counting model system has been set up. Through the comparison of the multi-redundant models, double parallel model is chosen as the designing plan with the reliability target as the standard. By combining the system developing levels with the application environment, the redundancy level was positioned in the model-level redundancy, A/D connected in series with the master as the redundant unit, the bi-processor models drive on outer model.Next, the research on the system realization has been made in both software and hardware. The hardware design mainly finishes the fault avoiding design in the master while the software design has a function of fault-tolerance, which improved the reliability and usability of the system.Finally, the theoretical analysis of the reliability of the axis-counting system has been made the reliability modeling adopts the combining and Markov model. By analyzing systematic math model, we get the reliability of the two strategies of returning maintenance as well as the increasing parameter.The paper is a fault-tolerance design facing the application of the railway axis counting. In some aspects, a realization plan of 1+1 is different for the traditional method, which not only improved the reliability of the axis-counting system but also provides the ideas of fault tolerance design of the reliability design in other bad environment.