The four points of the background image are the fixed points of the substrate. The back end of the background image is the storage position of the substrate, and the front end is the dry detection position. The electronic camera under the cotton roller is stripped off by the carding machine to photograph the net of the array muffler. The camera moves along the working width of the carding machine on the closed track. The optical principle is very consistent with people's visual observation, which is more advanced than the method of sampling and testing which depends on human factors in the laboratory. The neps, impurities and cottonseed fragments were analyzed for each meter of sliver. Compatible with all major PLL systems, it receives signals to control the valve, outputs feedback signals to PLC, shows when and where the valve is, controls and monitors the operation of the valve, and is installed on the upper part of the valve and controlled by internal J6 muffler button (or remote control). At present, the main products are imported from abroad, and the target is to replace the imported products. The market prospect is good and the potential is huge. It is estimated that the project will be completed before 2007 and can be applied to the main customer units of the enterprise, with an annual sales volume of 5-10 million yuan.