Development Of The Infrared Forward Scattering Visibility Meter

Visibility is one of the important meteorological factors,which has a great impact on human life,production,transportation,etc.,in the process of economic development,the impact is more obvious.In recent years,due to the low visibility leads to many traffic accidents.With the development of science and technology,in some developed countries,various forms of visibility automatic measuring equipment has been widely used.With the improvement of economic level in our country,the demand for visibility measurement equipment also increased year by year.In many ways visibility measurement equipment,the forward scattering type visibility meter with its good cost performance,flexible installation,the advantages of reliable performance,more and more favored by customers.In this paper,a forward scattering visibility meter is studied in detail.A forward scattering visibility meter is developed,which is based on the forward scattering visibility meter.The transmitter and receiver probe are installed in the same shell side,and the 22 degree angle and the scattering angle of the probe are 45 degrees.Small instrument overall appearance design,installation convenient and flexible.Launch unit part of the instrument adopts the automatic optical power control circuit design,through the collection and the change of the emission light source,optical power,to adjust the current of the light source,has reached the purpose of the light source output stability.At the same time on the emission light source modulation,as to reduce the interference of background light signal.Receiving unit through the signal conditioning circuit for signal filtering,at the same time,the application of phase sensitive detection method for small signal is extracted.Through the design of pneumatic system effectively reduce the dust pollution to launch receiving probe problem,at the same time with the corresponding filter to ensure the cleanliness of the air in the gas path.To avoid the secondary pollution problem of launch receiving probe.In order to effectively prevent strong light interference,designed the corresponding hood,through the hood shape design and processing of the hood lining to reduce stray light interference problem.Instruments have both communication and analog output interface.For the compensation of temperature influence through the fitting formula.Write the single chip microcomputer and PC debugging software program.Made a principle prototype,and for a long time in the field of prototype test,work stability.Instrument has the transition at present,the small batch production and formed sales.