Research And Design Of Tunnel Traffic Controller Based On The Linux And ARM

The construction is in a rapid development period at present, tunnel has become an important part in highway construction. But highway tunnel is seal and complex, it is also a black spot. Therefore, highway tunnel supervisory system has become an important part in saving the people's life and property safety in traffic industry.And the selection of controller in the tunnel monitoring system is related to its stability, safety and cost.With the development of computer technology and chip technology, more and more embedded chips and tiny operating system has into our life. How use advanced chip make into products, to improve our automation level, has become a research direction for embedded stylist.In this paper, a controller was designed, which was used in highway tunnel according to the monitoring system requirements. The embedded controller was designed based on the Linux operating system, and used structured and modular design.In order to adapt the terrible conditions of tunnel and improve controller's stability, signal of controller's I/O was isolated. The I/O could read digital signal and analog signal, and realize switch control. The controller has a RS232 communication interface, which is often used for debugging system and procedure download. In order to connect serial device, two RS485 interface support Modbus RTU protocol, and one is Modbus RTU host, another is Modbus RTU slave. Controller's Ethernet interface support concurrent server based on TCP/IP framework, it can also support multiple clients visiting the controller through Modbus/TCP protocol at the same time. We can improve store in system and IO upgrades easily by USB interface, SD interface, and expand bus interface.Different from traditional controller, controller which design in the paper use S3C2440 processor base on ARM9 structure, it can make the frequency reach 532M. Because system uses big Flash memory and SQLite3 relational database, it stores data and searchs historical data conveniently. In order to adapt to this situation which equipment widely distributed and interference is strong, the paper designed a photoelectric Ethernet module that support the SC fiber interface directly, in the end, its communications capabilities was improved greatly.The controller's program updates and function expansion is very convenient, because it uses the Linux operating system. The controller support C/C++ language and its program can download and run easily by RS232 port, USB port or Ethernet.