The Research And Application Of Fieldbus Technology In Protein Fibre Spinning Control

Nowadays the industrial control technology has been a fieldbus-based control system. Fieldbus, integrating digital communication technology, computer technology, network technology, intelligent meter technology, forms a fully-decentralized, intelligent and digital control and communication system characterized by bidirection, interlink, more-variable and more-node. Thus it gives a radical change to the framework of the industrial control so it is in the leading position in the development of Automatic Control.The control system for the protein fieber spinning adoptes an industrial control computer to link all the interters and temperature control instruments, and the signal is 4~20mA stimulant variable and 24VDC on-off variable. The present equipments are loaded down with trivial details. There is no interchange and commutative operation between the equipments among different companies. The stability and the maintenance of the system is not good enough, so if one of the equipments fails to function, the product line may stop. This thesis, armed with fieldbus technology, gives an improvement on the control system of protein fiber spinning product line.Based on the knowledge of the spinning technics of protein fiber, this thesis analyses the control objects and the control demands during each procedure, especially the two important parameters------spinning speed and temperature.This thesis deals with the spinning speed control in two parts: one is harmony synchronization, the other winding. This thesis gives a control project based on two-closed loop for longitudinal synchronization and winding, one-closed loop for transverse synchronization. PID control arithmetic is adopted for two-closed loop to ensure the control precision. According to the control project, this thesis suggests the buildup of the system, the choice of equipments, the design of the software.The equipments, ranging from the drying machine to the finalizing-two machine, aresimilar in terms of the oven structure and the mode of temperature control. In this way, this thesis introduces the control system to one oven of one machine. According to the oven temperature control, this thesis analyses the math model, introduces the fuzzy-PID mixed control to meet the control precision. The Fuzzy control adjusts big errors and PID control for small ones. Accordingly, this thesis introduces the buildup of the system, the choice of equipments, the design of software.Monitoring and controlling system is very important for the industrial control. This thesis designs the monitoring and controlling system with Kingview 6.5 and EasyBuilder 500 to monitor running state, to change technics parameter, to display real-time trendline and history trendline, to save product data, to output and print profile and so on.The progress of intelligent meters is indispensable to the development and application of fieldbus. This thesis has carried out a research on the designs of hardware and software for PROFIBUS-PA interface of intelligent sensors and demonstrates the application of intelligent temperature sensors in the temperature control of the protein fiber oven.The protein fiber spinning control system based on fieldbus has reached the leading level of the international control system. The application of fieldbus has improved the reliability and control precision, so has the quality of the protein thread, and then the rate of failure is reduced, the cost for setting is decreased and the system is easily-maintained, flexiblely-integrated.