Research On Arcnet Train Data Communication Network

As China's new generation of CRH (China Railway High-speed) train was put into trial run, marking the speed of the train improve to a new level, at the same time the security and comfort of the train become more and more important. As the transmission channel of train message and control instruction, train data communication network is particularly important. Therefore, it is essential to establish a train data communication network with high reliability, strong real-time and higher security.As a kind of optimal token bus technology, ARCNET (Attached Resource Computer Network) with its characteristics is so suitable for field control that also successfully applied in industrial automation. The ARCNET has such advantages as high reliability, strong real-time performance, quick transmission rate, time certainty and supporting long-haul communication and so on, so it is an ideal field bus technology. The ARCNET network is not only widely used on high-speed train in Japan, but also as the train data communication network of the introduced CRH2 Series train.First of all this thesis introduces the general framework for train data communication network based on ARCNET, train information transmission system, network transport protocol, train communication bus and train-level network structure and so on.Secondly it explicitly states the advantages of ARCNET network that suitable for train data communication network. It introduces frame format of the protocol, basic encoding unit, it mainly introduces the initialization of ARCNET network logical ring, node join and exit the network, data transmission and receiving process.In discussion of token passing method about protocol, firstly it analyzes traditional token passing method and the operation process of the method with train data communication network, simultaneously it points out that the traditional token passing method can't worked well for the application of node exit the network. Then a new token passing method that is Double Address Token Passing (DATP) is presented based on the traditional token passing method. The basic thought of this new method is simultaneously both record the address NID (Next IDentity) of subsequent logic neighbor node and NNID (Next Next IDentity) subsequent logic neighbor node successor logic neighbor node, and periodically update the NID and NNID values in the transport of message. Both ARCNET train data communication network and DATP token passing method are carried out to validate their feasibility and capability by means of OPNET Modeler, the simulation results showed that the main factors which influenced the end delay time and the BER (Bit Error Rate) to guarantee the normal running of ARNET network.While conducting theoretical research, this thesis also designed an experimental platform to verify the ARCNET network performance, and introduce the configuration of major equipment about the experimental platform. Due to time and funding constraint the experimental platform does not achieve, but the design fo the program will have play a exploratory and guiding role in the experimental platform construction.