The Design Of Mirror Dew Point Instrument With Double Light Path

Humidity is very important with our industrial,agricultural production and daily life.dew point hygrometer is used to measure the vapor of the gas.In this paper, Designed a dew point hygrometer with double optical path,based on the principle of cold mirror and photoelectric detection technology, mainly used to detect the gas of the industrial production.This paper designed a high-precision dual optical mirror dew point.uses the ARM core of the STM32 microcontroller, high-precision measurement circuit and control algorithms. Through the beam spilter, one of the measuring light road was directly by the photoelectric tube received, as the reference signal, and can automatic temperature compensation of the light intensity; the other path in the mirror was received by photoelectric cell after specular reflection and refraction.that all light can be focused on the measurement, no waste. The light signal was conversed by the photoelectric circuit.then controlled the refrigerator after enlarged. When water vapor in the gas is condensed on the mirror surface and reach the phase equilibrium state, measured by high-accuracy temperature measurement circuit. Therefore, achieve the accurate measurement of gas humidity.Because humidity measurement system is a pure delay system, a control method for time delay system is studied and simulation,used the improved control methods of smith algorithms,consequently,the measurement speed is greatly improved.The experimental results show that the design of the measuring instrument with high precision, high speed, low air consumption, good stability.