Research And Design Of Mine-used Broadcast Talkback System Based On CAN Bus

The broadcast talkback system is one of the critical infrastructures that stateregulations of coal mining enterprises must build, it mainly used for voicecommunications between ground dispatch center and miners, and it is a effective toolthat to achieve coal mine disaster emergency rescue and production commanddispatch, important to protect the lives and safety of miners, to improve the level ofcoal mining enterprises management, to improve production efficiency.In order to solve problems of poor communication real-time performance andpoor anti-interference ability exists in current coal mine scheduling telephone andlocal broadcast telephone, a broadcast talkback system based on CAN bus is designed.Entire system is mainly composed of industrial PC located in ground dispatch centerand communication master, communication sub-station located in underground, takeshield twisted pair as transmission cable, the voice signal after compression encodingto perform long-distance transmission through the CAN bus. The industrial PCthrough the operation of the communication master, achieve multi-mode broadcasttalkback with communication sub-station. Communication sub-station as anunderground broadcast talkback terminal, with voice signal acquisition and play, CANbus transceiver function.According to intrinsically safe design requirements and principles of mine-usedelectrical equipment to design communication master and communication sub-station,they are based on the ARM9embedded hardware platform, take embeddedmicroprocessor S3C2440and voice codec chip AMBE-1000as the core, to extend theCAN interface through the CAN controller MCP2515and CAN transceiver chipCTM8251T, S3C2440as the main controller of communication master/sub-station,AMBE-1000is used to implement the AMBE voice compression coding algorithm, toachieve2.4kb/s encoding rate, so that the voice signal suitable for transmission on theCAN bus. Hardware design of communication master/sub-station, it mainly includesthe main controller module, voice processing module, CAN bus interface module,LCD display control module and other peripheral circuits, meanwhile, in the design and chip selection of CAN bus interface, especially considering the EMI/ESDperformance enhancing interface, to adapt to the coal mine complex and harshenvironment.The communication master/sub-station through the WinCE operating system toachieve the task scheduling management of the program, it has good image interface.The main work of software design for: porting of the WinCE operating system,preparation of CAN interface driver, communication master/sub-station design ofeach functional software etc. and the design of industrial PC monitoring software.Tests show that, the system has good real-time performance and anti-interferenceability.