Design And Realization Of Central Control Unit In Diagnosis System For Metro Train

As the process of urbanization being accelerated in China, many cities speed up the construction of urban metro in order to relieve the traffic jam and respond to the call of the government to develop clear energy transportation tools. However, most of the metros are imported from foreign and depend most on the technology of these countries because of being backward in techniques early, especially the train diagnosis system. After years'operation, many equipments of the train diagnosis system have been ageing failure and some of them went out of production, which makes the fee of train maintenance very expensive. Thus, it is the time that we should localize those train diagnosis systems.Based on the topic named the localization of Line 4 train diagnosis system of Guangzhou Metro, this paper fundamentally finished the localization design of the CCU (Central Control Unit) of the train diagnosis system. After the deep analysis of its network structure and bus protocols, this paper retains the bus types of original diagnosis system, mainly conducts the software and hardware design of CCU.The Core of this localization diagnosis system is the CCU, whose functions mainly include train level ARCNET bus module, vehicle level RS485 bus module which be combined with HDLC protocol and the communication module with ATO and Vehicle Display. This paper adopts the ARCNET communication controller COM20022I to construct the loop network of train level ARNCET bus to implement train level communication; Choosing a HDLC communication controller SAB82538 with 8 channels to establish the vehicle level communication network between CCU and sub-system equipments; Adopting UART and RS422 communication chip to implement the physical level connetction between CCU and ATO and Vehicle Display, and the data link level protocol of them are BISYNC protocol and self-defined protocol repectively. Deeply analizing the bus communication real time of the diagnosis system, and conducting optimal design for the communication real time of CCU.In the final, through the test for CCU, the communication functions of CCU designed by this paper are certificated to fulfill the localization request.