Design Of Wireless Monitoring System For Train Operation

Security is the core in the process of rapid development of China’s railway construction.However, the method of traditional inspection, subject to the constraints of the distance andconditions, can’t guarantee the results on-site were transported to the terminal timely, so itbrings feedback of the result and pressure to safety of train operations.With the developmentof networking and intelligent system in the field of industry, monitoring systems of industryneed to be designed in the level of distribution network, to change the question of channelexpandability and mechanism of data security and parallelism with the traditional distributionmonitoring system. A topological structure with distribution network based on C/S moduleis presented in this paper to solve the problem of multi-point on-line monitoring in the field oftrack monitoring system. The wireless data transmission network is connected through GPRSbetween remote data service center and on-site unit. The on-site monitoring unit is built tohandle network management, simultaneous collection of data from each station and real-timemonitoring for state of every data collection.The unit of the data acquisition uses the parallel multi-channel collection station basedon Ethernet interface. Network management is based on multi-thread technology of VC++,and the signal processing is completed by using instrument control integrated inLabWindows/CVI. It realizes online multi-point remote monitoring of dual-track parameters.Specific studies mainly contain the following aspects: First,the Altera’s FPGA chip(EP1K30QC208) of low-cost and high density is used to control8-channel parallel A/D(MAX1320), and the collector can realize multi-channel data acquisition synchronously, thesampling rate attains20Hz-200KHz.The mechanism of cache based on double SRAM is usedto achieve real-time sampling infinitely under the condition of continuous acquisition.The unitof FPGA logic control and embedded PC module analysis user commands and data throughPC104bus interface, and the control unit is able to complete implementation and backing ofuser commands and data. Secondly, the writer of the paper write the software platform of theservice center with the mechanism of network management based on multi-thread technologyof VC++, so the data overflow of the site cache data caused by reading sequentially based onsingle-thread is avoided. The highest sampling rate of system is substantial increase by40%.The system assigns time slices to each thread, so that it will not lead to collapse of the systemdue to the failure of single acquisition unit. Finally, the program of waveform display andsignal processing is used by LabWindows/CVI on VC++platform. CVI control can supportus to achieve the seamless link from the data acquisition and signal processing to waveformdisplay, it greatly shorten the development cycle of the test software Developed in VC++. Thepanel of virtual instrument is designed with the function of channel signal eigenvalues (the most value, peak-to-peak, RMS, frequency, etc.) and cursor and scrolling timeline andwaveform stretching or zoom button, and the panel of power spectrum is designed to provideuser an opportunity to observe local characterized of the signal.We have built system to carry on simulation of single-site and multi-site, platform oftesting sets up two sites with each site has two collection terminal to meet requirements of therailway simultaneous monitoring about double track. We use Agilent20MHz Function SignalGenerator as a signal input device to carry on signal example simulation with differentfrequency or different waveforms or different amplitude on different acquisition mode. Theparameters of virtual instrument panel is the same to the signal input, and waveform operationis normal, the system proposed is capable of remote online monitoring with two sites for dataacquisition.