Study Of Methane Measuring Apparatus Of Interference Type Based On Linear Array CCD And FPGA

In recent years, the percentage of gas accidents in the total number of accidents which have happened is increasing , they have invoked the disaster for miner's lives. It should be strengthen the control of gas to prevent the danger of high-density gas and gas explosion ahead. So the fast and real-time monitoring of gas is of particularly significance for safety production of mine and environment protection.Portable Methane Detection Alarm is the most common first countries of a concentration of methane detection instruments, you may at any time testing the concentration of methane workplace, you also can use the methane concentrations of methane sensor for continuous real-time monitoring. Application of the current large portable methane detection apparatus, the principle of detection of methane into optical detector, the thermal conductivity of methane detector, thermal-catalytic methane Detection Alarm, methane-gas-sensing semiconductor detector, and so on.Ordinary optic interferometer methane monitoring device has good performance, long life span and high accuracy,so it is the most popular and convenient methane monitoring device in our country's mine. But it still has low automation level,fussy measuring methods, big artificial error,indirect reading and cannot store the date. In order to solve the problem, an automatic measuring method based on Linear Charge Coupled Device (CCD) and the interference of methane detector on the realization of the principle was presented. The displacement of interference fringes was measured accurately by using CCD drive,high-speed analog-digital conversion, data acquisition, and other key technologies. The concentration of methane was displayed by processing signals from linear CCD with a single chip computer.Detecting the position of the white base line and black base line in the interferometer stripe is the key. We use linear CCD imaging to obtain the position of stripe. CCD is a particular photo-electricity semiconductor,which is abroad used in camera,industry detection and other areas. The technology of CCD can realize high precise and non-contact detection requirement,especially in the accurate position detection. The system uses FPGA as RAM address generator and CCD Chip's driver. Use of FPGA makes the implementation of the CCD chips driving faster, and more stability.The data after analog-digital conversion is not used memory chips for storage and the use of FPGA hardware development platform and Verilog HDL hardware description language to write code modules for data acquisition systems, At the same time they increase the precision of improving data collection function, both reducing cost and improving the efficiency.The system has excellence of using convenience,high precision,and can store the data. Via solve the disadvantages of ordinary optic interferometer methane monitoring device, the new system we design improves the technical index and function greatly.