The NCL-2401 ultraviolet flue gas analyzer is an optical analysis instrument that uses ultraviolet differential absorption spectroscopy (DOAS) technology as its core to determine the concentrations of SO₂, NO, NO₂, O₂ and other components in exhaust gas from fixed pollution sources. The instrument core adopts imported optical components and has the characteristics of high measurement accuracy, high reliability, and fast response time. Measurement principle: The ultraviolet emitter emits an ultraviolet beam with a determined spectrum to the receiver; When ultraviolet light passes through the sample chamber in the optical path, it is absorbed by the measured substance. The absorbed ultraviolet light signal is transmitted to the spectral system in the spectrometer for spectral analysis, and then projected onto the CCD array. After being converted into an electrical signal by the CCD array, it is input into the computer for processing to obtain the gas concentration in the detected area.