The ultraviolet light weatherproof test box light source uses a fluorescent ultraviolet lamp. The fluorescent ultraviolet lamp will age itself during use, and the irradiance will decrease. The old ultraviolet light weathering test box has no irradiance monitoring system, and the UV lamp and position rotation are periodically replaced. To achieve a relatively stable irradiance within a certain period of time. With the development of technology, the new UV weathering test chamber is generally equipped with an irradiance monitoring system to ensure the stability of the irradiance. Correspondingly, new standards or standards for fluorescent UV lamp exposure tests generally have irradiance regulations. The irradiance specified in the test standard determines one aspect of the amount of light source (on the other hand, the duration of the irradiation). Irradiance is the radiant energy received per unit area of ​​the surface of the sample, generally in W/m2. At present, there are two main monitoring spectral bands used in the ultraviolet weathering test chamber: 1, 340nm, for the monitoring of fluorescent UV lamps UVA-340 and UVA-351; 2, 310nm, for the monitoring of fluorescent UV lamp UVB-313; The irradiance monitoring system monitors the irradiance through the optical probe to adjust the power of the lamp and keep the irradiance stable. The irradiance monitoring system requires regular calibration. Small Tape Measure,Snap On Tape Measure,Fiberglass Measuring Tape,Construction Tape Measure HENAN 95 MEASURING TOOLS CO.,LTD. , https://www.95tools.com