Design Of Plastic Extruder Master-slave Control System

Plastics extrusion line is a mechanical equipment to produce plastic sheet based on the vinyl chloride, polypropylene as raw material, plastic sheet can be made into folders, plastic cups, lunch boxes and other plastic products through further processing. The production unit mainly consists of feeding system, heating extrusion system, cooling system and traction winding system. Now the integration of industrial automation and informationize technology has become the mainstream of current industrial control technology development trend. In this paper, plastics extrusion line control system has been researched in order to design a satisfactory plastic extruder control system for the future demand. The main research content is as follows:(1) Design a plastic extruder control system based on touch screen and PLC through analysis technological process and control requirements, build the hardware platform and write the system software. The hardware platform of the system is built based on the Profibus communication, and the touch screen act as master controller, PLC as slave controller. Software in the touch screen was developed through MCGS, and control program in PLC was written by Setp7. The resultant performance of the developed controller has shown it to be a satisfactory alternative. In order to facilitate the expansion control function to control layer, the system reserved remote monitoring interface.(2) Due to the high requirements of the temperature and pressure control during the production, in this paper, the relationship between temperature and pressure under the circumstance of certain main motor speed has been figured out through analysis the extruder structure. The traditional PID temperature controller is characteristic of time lag, and a nonlinear, a new multi-loop temperature controller is designed. Experimental simulation is carried out in this paper, the result show that the new type of PID controller responses quickly and accurately.Site commissioning and trial operation results show that the design of plastic extruder control system can satisfy the demand of plastic sheet production process, the desired design target.