Proportioning scale and feeding scale use proportional integral differential (PID) control algorithm in the control system. The control system with PLC as the core, continuous control of multiple control loops, using frequency converter to control the speed of the spiral Feeder motor, incremental PID control algorithm. The whole production process of mixing is mainly divided into loading section, dosing section, mixing section and storage section. According to the process characteristics of the Batching system, the lower machine program includes the following parts: system initialization subroutine: System initialization, read the PVC production process control parameters, first check the status of the silo, detect that the silo is not empty, then check the current value of the batching scale and feeding scale, in the case of the scale value is relatively "zero", the batching process is carried out, the batching is finished, then the mixing process is implemented, and finally, the material is discharged and the finished material enters the storage bin.

Feeding system control procedures: The control program of the feeding system mainly completes the function of feeding the material in the distributing bin. The system detects the position switch of the unloading level of the distributing bin in real time. When it is effective, the system gives the indication of the material shortage and automatically starts the feeding fan, and sends the ingredients to the distributing bin by means of air power from the pouring station of the proportioning. Turn on the pulse spray for 5 minutes to clean up the dust caused by loading.

Feeding system control procedures: The feeding system control program mainly completes the feeding function of the auxiliary material bin. When the system detects that the level meter switch of any auxiliary material bin is effective, the system will give an indication of material shortage, inform the feeding of auxiliary material, open the feeding fan, close the feeding door after the feeding of auxiliary material, cut off the corresponding position switch, close the feeding fan and dust removal fan in sequence, open the pulse spraying for 5 minutes, and clean up the dust caused by the feeding. Batching system control subroutine: In the batching process, according to the characteristics of PVC batching equipment, the method of dynamic control is adopted, and the actual value of the batching scale must be compared with the raw material weighing value set by the formula in real time during the batching process.

Mixer control program: The mixing system control program realizes the material mixing after the auxiliary material warehouse is finished, and the control parameters used must be configured before the system mixing.

The control subroutine of the material storage system: the control subroutine of the material storage system realizes the function of the final material storage. When the system detects that the loading level of the storage bin is effective, the loading level of the transition bin is invalid; when the loading level of the transition bin is effective, the corresponding feeding fan is started. When the loading level of the transition bin is effective, the fan is shut down and the pulse injection is started to remove dust after a delay of two minutes.

Weighing instrument value reading program: It is mainly used for reading weighing instruments and completing simple data processing functions. Alarm subroutine: When any of the following situations occur, give an alarm and stop the relevant equipment: the hot cooling machine cover is not closed, the motor protection switch is effective, and the storage bin loading level meter is effective. Sound and light prompt when any bin is empty or full. Manual control subroutine: When the system fails, the program is used, at this time, the upper and lower machine only plays the monitoring function of the system, can not operate the system, the system is equipped with manual and automatic control buttons.