Developmet Of Leakage Communication System Based On Coal Mine Local Network

Leakage communication system is one of the most frequently used communication tools in underground mines. Coupled with the telephone lines in mines, it can effectively carry out the telecommunication tasks for people working underground and those working on the ground. A major drawback of such system is that the communication process is rather complex and there would be a time delay in the communication. Following the fast advanced in information technology and the rapid expansion of the communication industry, mining companies nowadays are demanding better and more reliable communication systems which can convey information instantaneously and in secure manners. The existing communication tools fail to meet this requirement which motivates the development of an alternative system as presented in this study.This study presents a modified leakage communication system based on the local telecommunication network of a mining administration bureau to overcome the problems of traditional communication tools, and to meet the demands of mining companies. Besides an overall system design, this study focuses on the design of the most critical connecting device in the communication system including both hardware and software design. The hardware design includes the selection of electronic components and the relevant circuit design. The software design consists of the embedded μ C/OS-Ⅱsystem design, Serial Peripheral Interface(SPI) communication protocol development, network programming and the program design for the audio signal acquisition process.The connecting device serves as the link between the leakage communication system below ground and the control room above the well. It uses the combined Advanced RISC Machines(ARM) and Digital Signal Processing(DSP) as the control chip in which ARM serves as the core processor to handle the data transmission, command analysis and execution while DSP encodes, decodes and passes on the audio signal. The execution of data and command transmission between ARM and DSP is carried out using the SPI communication protocol. Data and command transmission between the hardware system and the upper computer is accomplished by network programming to realize a seamless connection between the leakage communication system and the network.Experimental testing result shows that the performance of the embedded communication system presented in this study is rather stable. The ARM chip can effectively control the DSP using the SPI protocol and the network communication works well in transferring data and command between the hardware system and the upper computer. The modified communication system can successfully meet the requirements of mining companies in terms of audio quality, operability and security, and can be employed in mining communication.