Data Transmission Research Of Train Air Brake Testing System

Train air brake testing system is an integrated system, involving wind execution equipment, rear air pressure detection equipment, communication system and industrial computer etc.The labor intensity and density of train air brake testing operation is continuously strengthened. These have put forward higher requirement for system’s real-time and reliability. Now, system of train air brake testing is composed of ISM (Industrial, Science, Medical) band wireless network and RS485bus as its internal communication. Communication efficiency has a significant impact on the system performance.This paper focuses on the method to improve the efficiency and reliability of the communication system. The main achievements of this paper are as follows:(1) In this paper, the overall structure of the existing system is optimized. For the management of testing process and wireless communication, network manager and gateway are added respectively. These reduce the operating load of industrial computer and bring a significant promotion of communication system’s reliability, flexibility and maintainability.(2) The hardware optimizations are carried out. First, instead of the existing RS485bus, a complex bus with RS422bus and alarm line is introduced. Second, the interface of gateway and bus connection are redesigned for hardware anti-jamming of power supply and data exchange. These improvements bring beneficial results in communication efficiency and system capacity of emergency response.(3) The software optimizations are as follows. By reducing the DTMF code length and redesigning the communication protocols of bus and wireless, data amount of communication is decreasing. Especially an adaptive packet size setting method and selective retransmission mechanism are brought in to improve the reliability and adaptability of the network environment for wireless communication.(4) With the above optimizations, a new train air brake testing system is present. The experimental results show that good effects have achieved in improving the efficiency and reliability of data transmission in the system.