The weighing mixing system takes the industrial computer as the upper host and Siemens PLC, frequency converter and weighing instrument as the lower slave. The host is in the dominant position to realize the communication management and control of each slave computer. The RS-232 asynchronous communication interface of the industrial computer is connected to the PLC after the level conversion to form a physical channel for the communication between the upper and lower computers. In the production process, all kinds of raw materials must be evenly mixed in strict proportion, it must be completed by ingredients, in order to ensure product quality, the raw materials are evenly mixed together in a certain proportion to form a new material.

Pneumatic conveying is a conveying technology that uses the energy of compressed air to carry out continuous conveying of bulk materials. One main conveying pipeline is used to transport powder to four mixing machines, that is, there are four branch conveying lines, with a total conveying length of about 150m. Each branch line delivers to 8 storage tanks, for a total of 32 storage tanks. In the process of powder conveying, the key to achieve the best ratio of powder material to gas is the control of the inlet of the pressure feeding tank, including the pressurized inlet inside the pressure feeding, the fluidized inlet, the main conveying inlet and the auxiliary pipe inlet. The pneumatic conveying system adopts the external bypass intelligent double-pipe conveying technology. After the conveying system is started, the target tank is selected and the corresponding pipeline fork valve is operated, and the powder enters the pressure feeding tank from the unpacking device, and is pressurized and fluidized in the pressure feeding tank. During the conveying process, the powder flows in the conveying pipe in the state of dune flow and plug flow. According to the pressure change of the weighing module and the pre-set pressure value, the auxiliary pipe determines whether to replenish compressed air into the main conveying pipe. Aeration makes the material cut into sections of the material bolt move forward in the pipeline, and can prevent the pipeline blockage, and finally enter the storage tank. The material in the tank is separated from the gas by its own weight, and the gas is filtered by the dust collector and discharged by the fan.