Development And Realization Of Wireless Date Terminal In Digital Mine

In order to improve the efficiency of mine production,reduce labor intensity of underground workers,and enhance the safety of these workers,there is a strong need to develop a data terminal communications systems based on mine.According to the actual needs of the current mine production and current situation of wireless communication based on mine home and abroad,this paper propose a WLAN date terminal system based on mine.And adopting ARM9 processor chip EP9302 as the systematic core of hardware core,transplanting embedded Linux as the operating system,we developed and realized an embedded system based wireless data terminal.Throughing remote control of the wireless data terminals,the system main control center is capable of sending dispatching instructions and inspection messages to the works underground;controlling underground equipments;monitoring of environmental parameters collected by sensor network witch connected to the terminal serial port.When abnormal event occurs,works can press emergency call button to send alarming signal to monitoring center on the ground,in order to get the related staff taking effective measures.This paper first build the hardware platform of the terminal board,and then set up the software platform based on embedded Linux operating system,including the establishment of cross-compiler environment,configuration and compilation of embedded Linux kernel,making a ramdisk.Finally,we add a wireless module for this terminal board,transplanting the IEEE 802.11b wireless adapter driver to this board.In this paper,we mainly design and develop an application program under the embedded Linux environment.First of all,the network communication based on TCP protocol is established between terminal board and control interface by using sockets. Then multi-tasking system is achieved by using multi-threaded technology.This system is an integration of several terminal function modules,such as short message transmission,devices controlling,monitoring of environmental parameters,emergency calling.In data transmission,an application layer data message format is designed in order to carry different types of information structure.The process of sending and receiving this message format is also designed.In the message sending threads of different functions,a kind of message queue is designed to keep in information structure temporarily.The input and output of message queue is designed by using mutex and semaphore so as to realize thread exclusion and synchronization.After designing and debugging of this date terminal system,we make a real test in the coal mine tunnel underground.Firstly,functional tests are carried out to verify the feasibility of this system.And then we make an analysis of packets captured through the communication of the wireless date terminal,to receive the process of communication and the scope in which this date terminal can by well used.