Monitoring And Measurement System Of The Ponded Water Level In Mine Based On CAN Field Bus

The safe production in the coal mine is affected by hydro-geological disasters. Currently, the domestic coal mine monitoring system mainly adopts the distributed control system, which consists of master-slave architecture, takes time-division communication as the mainstream technology. And the underlying monitoring equipments could not exchange information mutually. Besides, because of the limitations of sensor technology, the mine water level monitoring system can not cover the whole working environment, and is arranged only in water warehouse with better working environment. Therefore, the water level information of tunnel can not be gathered, which reflects the change of hydrologic information. This results in low detection accuracy and slow response of the system, and could not alarm in time and forecast the hydrology information.Aiming at the existing problems of mine water level monitoring system, a new monitoring system is designed to cover the entire coal mine working environment. The core technology is a new water level sensor, which is based on the principle of variable dielectric capacitor, transforms the water level to corresponding capacitance value by Teflon coaxial cable, and then transforms the capacitance value to the standard voltage by the special circuit. Finally the average filter and interpolation method are synthetically used to fit the system characteristic curve, and eliminate interference errors, thus the nonlinear correction was implemented at last. The mine substation is designed with the core processor of microcontroller MSP430F169, which aim at the compatibility with existed mine sensors and the lower cost of the monitoring system. A data interface for variety of sensors is designed, which not only read the sensor data, but also could read the traditional analog and switch level sensor data. After reading the sensor data, the analysis by the core processor and the automatic exclusion of underground water by the way of one by one, the data is transmitted through the CAN bus to the monitoring center, displaying real-time water level. When the water level is above the warning level, it can warn in time. In order to realize the data exchange between the bottom devices to break the limit from "information island", the CAN bus is used for the communication among equipments. Compared with the existed CAN controller and transceiver,the MCP2515is selected as CAN controller, and the TJA1040as CAN transceiver, the two parts constitute the CAN bus communication module, achieve the function of sending and receiving by application of CAN bus. The man-machine interface based on configuration software is designed to remote monitoring of the underlying device.The result of test shows that the designed sensor has higher detection accuracy, and its non-linearity error is reduced to0.3205%, meeting the requirements in a complex environment. Mine substation can acquire the data signal which is sent from various types of sensor, can timely control the water pump, and finally achieve the compatibility of various types of sensors and the purpose of reducing the cost. CAN bus communication greatly improves the rate of data transmission, and makes the information transmission accessibility between monitoring systems by linking up the bottom equipment. Mine water level monitoring system can complete all established functions timely, accurately, and efficiently, meet the working requirement. Man-machine interface realizes a remote view of the historical data of the water level monitoring sites and alarm data.