The Design Of Infrared Methane Concentration Monitoring System In Coal Mine Based On ZigBee

Prevention of coal mine accidents has always been the top priority of China's safety supervision and management.At present,most coal mine safety monitoring systems adopt the form of wired network,which have problems of difficult wiring,high maintenance cost and poor scalability.The environment of underground coal mine is complicated,which may cause monitoring blind spots.The main component of gas is methane.Therefore,it is significant to design a coal mine safety monitoring system with convenient networking,good flexibility,safety and stability.Based on the study of existing methane detection technology and short-range wireless communication technology,a solution for the infrared absorption methane concentration monitoring system of mine based on Zig Bee wireless communication technology is presented in this thesis.After analysing the main functions and technical requirements of system design,the hardware of each Zig Bee node and its peripheral circuits is designed.Through the software programming and debugging the system function is completed.This system is composed of downhole data acquisition system and uphole monitoring center to realize the collection and processing of the methane concentration data in the mine,and finally transmits it to the monitoring center for display and operation.Downhole data acquisition system consists of three types of Zig Bee nodes,including terminal,router and coordinator.The CC2530 chip is selected as the processor.The terminal node's infrared methane sensor is responsible for detecting the methane gas in the mine environment,and the collected concentration voltage signals are transmitted to the control chip.After processing,the signals are transmitted to the router node by Zig Bee wireless communication.The main role of the router node is to expand the transmission distance.On the one hand,the router node judges the received methane concentration information,if the alarm threshold is exceeded,the system will send an audible and visual alarm;on the other hand,the data will be forwarded to the coordinator node to extend the transmission distance.Coordinator node is mainly responsible for the construction and maintenance of Zig Bee wireless network,and packs all the terminal information to the computer of the monitoring center through the corresponding serial port,which will facilitate staff to view and operate.PC software program is developed to display real-time methane concentration information,view the historical concentration curve,and set the alarm threshold.The system was tested to achieve the acquisition of methane concentration data.While methane gas concentration below 2%,the detection error is no more than 0.01%.Through the test and analysis of the function of each part,the system has been proved to be highly feasible.