Research And Development Of Precision Thermometer

Temperature is an important parameter in our daily life and production activities. It is ofgreat significance to obtain temperature information fastly and accurately. It can follow thetraditional standard mercury thermometer as a standard of precision measurement and valuetransfer, especially in the industrial field temperature ranges range from-60℃to300℃.Standard mercury thermometer can not achieve the real-time collection and transmission ofmeasurement data, and does not meet the requirements of intelligent temperature. All of thesedue to its material properties and other factors. Improper operation and the measurement islikely to cause mercury Spills. It is a potential hazard and pollution to human health and theenvironment. Prohibition and restriction the use of mercury has became the irreversibleconsensus and trends worldwide. Therefore, it is necessary to research and develop aprecision thermometer, which is an intelligent, high-precision and high stability temperaturemeasurement system, not using standard mercury thermometer. This topic is developed basedon this. The main contents are as follows:Firstly, each part of the design process is modular during design process in terms ofhardware and software. This paper gives a brief introduction about the main modules, such asthe hardware part of the SCM system, dual-channel A/D, and precision constant currentsource. And shows a detailed instruction about the design of the constant-currentcommutation circuit, the temperature measurement circuit by using ratio method based on keytechnologies, particular the homemade precision platinum resistance sensor, which has beengiven the describtion about the whole process from selecting the welded filter package to howto prepared. In terms of software design, several mutually independent programming anddebugging functionality of the program modules are called by the main program. This papergives the software flow of precision thermometer.The second thing is to make the precious platinum resistance thermometer indexing carryout experiment. First i adopt the ITS-90international temperature scale-fixed-point methodto dividing precision platinum resistance thermometer, and the experiments have been carried out to study the method;Then based on CVD equation method, i adopt the method of standardplatinum resistance on the score to dividing precision platinum resistance, and makeexperimental study. According to the experimental results, i determine to use the equationwhich is based on CVD method dividing precision indexing method of platinum resistancethermometer.The third is to develop high precision thermometer for stability testing and experiment oferror, and compare with standard mercury thermometer;To develop high precisiontemperature measuring instrument and the standard mercury thermometer, i analysis theuncertainty and compare the uncertainty of the two equipments. Based on the experimentsand the uncertainty of data, the resault shows high precision thermometer is superior tostandard mercury thermometer and precise temperature measurement can be performed.