The Construction Technology Research Of Karl Fischer Two-Channel Instrument For Measuring Trace Water

With the development of production technology and scientific research,the water content of industrial products will affect the control of the production and the quality of the produc. The instrument for measuring trace water is widely used in the petroleum chemical industry,the national defense industry and quality and technology supervision,etc.Karl Fischer method is still the most accurate and reliable in the methods of measuring trace water. At present ,the two most popular Karl Fischer methods are Coulomb method and Volumetric method.Two kinds of measurement methods measure are in different ways and each has advantages an disadvantages.So,they are suitable for different field.At present, the domestic Karl Fischer instruments are all single channel designed, namely the system can achieve only one method of measurement.This paper proposes a new project for two channel Karl Fischer instruments ,using the MSP430F2617 processor of TI as the core.The new instrument can use two methods for measuring in the same time.This paper firstly introduces the background of subject, analysis the technology of trace water measurement in country and abroad, expounds the principle of Karl Fischer method, makes a new project of Coulomb method, Volumetric method two-channel design and introduces the design of hardware circuit, including the Coulomb method channel titration end-point indication circuit, electrolytic current occurs and control circuit, blank current compensation circuit and Volumetric method channel the precision injection pump drive circuit and polarization voltage detection circuit, etc,according to the characteristics of the instrument designs the system software, expounds the function of each module program and design the related experiments to test the accuracy and stability of the instrument,makes a analysis of the measurement error, and finally summarizes the research content.The designed Karl Fischer Two-Channel Instrument for Measuring Trace Water in this paper has come intoexperiment stage,had good effectiveness and fulfilled the design demand.