Ice Layer Thickness Measurement System Based On The Capacitance Difference Of Air,Water,Ice

In recent years, extent of the polar glacier and the inland plateau glacier melt is comparatively big , great river , great river all exist ice run problem in north area of our country besides. Essential acquaintance glacier thawing and occurrence of icicle will be not to get away to measure thickness of ice layer. According to this ,the new method of measuring ice layer thickness has been put forward on the base of the difference of air,ice,water capacitance in this thesis. All that Capacitance values of three medium exist difference of order of magnitude were discovered by the fact that large amount of experiment result analysis, capacitance value measured can be changed into digital signal or frequency that the single chip may measure, since capacitance value exists upper difference of order of magnitude, when the sensor is measured point-by-point ,show being that the measuring medium has become another one kind from one kind if frequency sprung, As long as Change is measured out twice such springing, so (we) can resolve upper and down interface of ice layer, difference of interface is thickness of ice layer. The following will introduce entire systematic design concretely.(We) have introduced the structure of capacitance sensor of measuring the ice thickness mainly in the main body of the thesis, the adjusting circuit of frequency or digital signal changed by capacitance, data handling circuit and display and process of upper machine. Capacitance sensor structure is composed of the multiunit flat capacitance arranged according to the same gap, design selection circuit of every capacitance inside. Signal adjusted circuit has designed three kinds of adjusting way: One kind is that the reality of changing capacitance into frequency adopt special chip AD7745; adopt the different oscillating circuit to realize capacitance changing into frequency besides two kinds. It completes acquisition direction and runs to collect data in signal adjusting circuit and sends collecting data to the circuit of data process. The data handling circuit is the circuit taking single chip as core including clock,memory, communication etc. Not only clock circuit provides ' the real time for measurement, but also the interruption signal producing one time of a minute is used to be that single chip sends the collection instruction to signal adjusting circuit. Since data transfer can have a mistake or possibly be lost in sending data, also possibility upper machine does not accepting data in real time, therefore the data circuit having designed memory can be used to make up data in the future. The displaying and disposing program of upper machine is composed of data memory,data analysis and process and display of reaching the ice layer thickness according to experiment data. Communication has three kinds way mainly: The first kind of way is the communication making use of serial port and upper machine, is suitable to the close quarter data transmission; second kind of way is Be that making use of RS232 to CAN bus realizes distant transmission of data and many sensor networking control; Third kind of way is that the distant sending data is realized by the GPRS/GSM module.