Research And Realization Of Remote Terminal Unit For Railway Electric Power Based On ARM-Linux

Railway power telecontrol system plays an important monitoring role for railway10KVpower distribution station and self-closing or run-through power line and the signal powersupply, however remote terminal unit as one of main component part in the system, it mainlyused for data acquisition and monitoring load switches. In this paper it applied theARM-Linux technology and developed the remote terminal device for railway electric power,which has high performance, large capacity of data acquisition, strong communication abilityand easy maintenance.Through the research of the structure of railway power telecontrol system and analysis ofthe functional requirements of the remote terminal unit, it puts forward the overall designscheme of the hardware and software system. The device used "ARM+DSP+MCU" multipleprocessors working together for hardware architecture, and it choosed ARM11microprocessor chips S3C6410as the core control processor. According to the distributeddesign patterns requirement, each module of the remote terminal unit in the form of boardplug-ins installed in the case, also each module communicates with others by CAN bus. Tothe hardware realization, this paper focused on the layout structure of the main board anddesign of peripheral expansion circuit. For the design of the software system, based on theanalysis of the overall process of software system structure, it realized the bottom devicedrivers and upper application software programs running independently and interoperableaccess, through transplanted embedded Linux real-time operating system.In the process of transplanting embedded Linux operating system, designed theBootLoader console functional menu, also research and realized online upgrade Linux kernel.Designed of CAN device drivers of the main board part, it used frame structure of networkdevice driver. Communication of CAN data frame realized that SocketCAN communicationmode based on embedded Linux2.6kernel. Designed of the application software multitaskingprocess with the method of multi-threaded programming, and used thread locking mechanismto avoid the conflict phenomenon of reading and writing data, because the threads shareddata.In this paper in order to achieve strong communication compatible ability, remote terminal unit supports more communication protocols. Primarily designed of powertelecontrol standard communication protocols IEC-60870-5-101and IEC-60870-5-104whichused in the communication between remote terminal unit and scheduling master station. Andcustomized the communication message format of CAN application layer in the inside ofremote terminal unit, also research and realized data processing of CAN received. In additionto solve the problem of maintenance difficult and complication as result of using a serial portdebug maintenance, designd of the remote maintenance system for remote terminal unit byintroducing embedded Web server and used CGI technology principle, realized the remotemaintenance function for remote terminal unit. After running tests in power for remoteterminal prototype, the device met all aspects of the design requirements, and it wascompletely capable of the task for data collection and monitoring in the railway powertelecontrol system.