CLD-200, CLD-500, CLD-1000 digital dust measuring instruments are light scattering fast dust measuring instruments with laser as light source, using 90-degree laser scattering technology, can accurately find the "cut point" for each particle . The instrument is designed according to the enterprise standards of MT/T163-1997 "General Technical Conditions for Direct Reading Dust Concentration Measuring Instruments" and Q/320581ESD005-2014 "CLD Series Dust Concentration Measuring Instruments". The instrument uses the principle of light scattering to detect dust, and calculates the detection data through the microprocessor. The dust mass concentration obtained by the calculation will be directly displayed on the large-screen liquid crystal display, and converted into data signal output. The instrument can also randomly record the first 100 historical detection data, and can be connected with a computer to centrally process and print the measured data. The instrument is equipped with a grading dust collector, which can collect respiratory dust and total dust and PM1, PM2.5, PM5, PM10. The technical indicators of CLD-200, CLD-500, CLD-1000 digital dust measuring instruments have reached or exceeded the international advanced level, and can be widely used in the monitoring of dust concentration in public health, environmental protection, labor hygiene, occupational hygiene and other departments .