Y09-SS type/5102 online laser dust particle counter is used to measure the size and number of dust particles per unit volume of air in a clean environment, and transmit the corresponding particle number to the host computer through MODBUS485 communication. It can control the clean environment with cleanliness level of 100,000 to 100. This instrument uses imported semiconductor laser light source, small size, light weight, high detection accuracy, computer control, as long as the instrument is powered