Data Acquisition Platform On Fully Mechanized Coal Mining Face Based On Power Line Carrier

Coal, mine safety monitoring system plays an important role in protecting the safety production in mine. With our country's increasing requirement for the safety production in mine and the development of communication technology, new demands have been brought to the digitization, intellectualization, and automation in coal mine safety monitoring system.Coal mine safety monitoring system is made of ground primary station and downhole data collecting secondary station. The data collecting secondary station is used to collect and preprocess the data from the sensors.The ground primary station is used to process the data. As a transmission media, the data collecting secondary station is placed between the sensors and the ground primary station. Data collecting secondary station in coal mine safety monitoring system is focused by this dissertation.Three main parts are include in the design of data collecting: secondary station the first part is the design of power line carrier module in the fully mechanized coal working face. The power line carrier module in the fully mechanized coal working face uses power line carrier communication technology and uses downhole 127V power line as the communication channel between the primary station and data collecting secondary station.Existing power line is adapted to transmit data without setting up new transmission circuit, which reduces the great trouble of arranging the communication data line and saves lots of money. The design of carrier communication module mainly includes design or carrier signal coupling circuit, carrier signal filter circuit, carrier signal transmission circuit, carrier communication demodulator circuit with MC3361BP as the core. It uses C8051F330 and timer interruption method to produce FSK that is needed by carrier transmission, and then sample judge the post- demodulation baseband signal through digital sampling.The second part is the design of flameproof and intrinsically safe UPS module. The flameproof and intrinsically safe UPS module is a power supply with intrinsic safety character designed to prevent the downhole flame and explosion. Design of the flameproof and intrinsically safe UPS module mainly includes design of three parts:battery power supply circuit, 127V power grid power supply circuit, and input over-voltage detection circuit and output over-current detection circuit. Through the 12V direct-current output produced by intrinsically safe power supply module, the intrinsically safe power supply module supplies power safely for power line carrier communication module in the fully mechanized coal working face and data collecting module.The third part is the design of data collecting module in the folly mechanized coal working face. The data collecting module in the fully mechanized coal working face is used to collect data from the downhole sensors. It uses STM32 as CPU to control the core circuit.This paper designs acquisition circuit to collect data of underpit sensor current signal, frequency signal and on-off signal. Then it finishes the designs of the CAN bus interface circuit and the RS485 interface circuit and to transmit data of smart sensor containing RS485 interface and CAN bus interface. The data collecting module and power line carrier communication model use UART to communicate.The design of three modules in data collecting secondary station is finished and the material object is made. Then each module and the whole system are debugged,the reliable operation of data collecting secondary station in the fully mechanized coal working face based on power line carrier communication is achieved.