Closed-loop Control And The Simatic S7-400 Plc Technology In Tobacco Redrying Process

With the fast development of micro-electric technology , the function and characteristic of PCL product have consumedly enriched and improved , this is the base of a series of advanced-control and technology innovation . This article is based on the analyze and summation to the principle and technological character of the closed control and PCL technology , connect with the actual facts of technical parameter and machine in the tobacco_redrying, deeply analyzed the application of closed control and SIMATIC S7—400 PLC technology in the course of tobacco_redrying. It has considered that some special function model of S7—400 PLC and I/O model control each technical parameter in the tobacco_redrying machine with closed control.The competition of the tobacco re_drying market is stronger and stronger day after day , in order to meet the upriver customers' high quality demand on the re_drying manufacture , we must have been escalated and improved the key equipment of re_drying line , and the improve to the re_drying machines' automate system is imminent .The process of tobacco_redrying is a complex process with lagging ,uncertainty and being nonlinear. Punctually setting up the mathematical model of tobacco- redrying's process is very difficult. Therefore, the usual open_control system or common PID control system can't exactly control each technical parameter in the process of tobacco_redrying. In order to satisfy with the actual needs of each performance index in the process of tobacco_redrying , we should design the closed control system , choose the SIMATIC S7—400 PLC , and connect the usual PID with the fuzzy control .The main study connects of this article were as follows:1. the connected basis theories : the connected knowledge of open_control and closed control, the function and technique idiosyncrasy of PLC technology , the basic principle of PID and fuzzy PID .2. Introduced the condition of tobacco_redrying machines' control system, analyzed the disadvantages of the former control system .3. Studied the technological principle of tobacco_redrying machine , the designed principle of electrical control system , the task that the electrical control system should completed and so on, furthermore, I connected the theories with the facts, put forward a full new program about electrical control .4. Analyzed the reason of choosing SIMATIC S7—400 and the technique idiosyncrasy of SIMATIC S7 — 400 PLC, deeply studied the applied programming, monitor system designing and transducer's communication of SIMATIC S7—400 PLC in the process of tobacco_redrying .5. Setting up the mathematical model of tobacco_redrying's process, studiing the designing of fuzzy manipulator, exactly studying the control of the closed control and fuzzy PID to temperatures and moisture in the process of tobacco_redrying .Besides , this article has analyzed the effective of closed control and SIMATIC S7—400 PLC technology in the process of tobacco_redrying. It's proved that the tobacco_redrying machines' control system can work steadily ? control faithfully , each technical parameter is very good .