The suspended solid sensor adopts infrared light technology for measurement. The instrument Analyse these data that are obtained by infrared light through the medium to the detector. It can know the exact concentration of suspended matter in the medium. It has the same accuracy and continuity when measuring low or high ranges. Besides, in order to effectively eliminate the deviation of data due to some changes of environment, so that it can be used in more environments. It is widely used in the monitoring of SS concentration in solution, such as Chemical, electroplating, paper making, ETP/STP/ WTP, Pharmaceutical, Food, water, etc.