| With the development of control theory, communication technology and electronic technology, the traditional batching control system also has to face the revolution of informatization and automatization. Some key techniques of automatic control for glass batching control system are studied in this paper and have been used in the project of the 400 T/D glass batching of the Shandong Linyi Glass Group Company Limited.Firstly, this paper introduced the glass batching process flow and the characteristics of existing batching control system. Aiming at the precision requirement of weighing system, weighing sensor and weighing terminal were analyzed and chosen in the passage.Secondly, because the traditional PLC systems connect I/O devices to the I/O blocks of PLC, control and monitor the local equipments by the analog signals of 4-20 mA and 24 V DC, so the signals are easily disturbed in the local environment. To solve the problems, the Fieldbus Control System is introduced and a distributed PLC control system based on the protocol of PROFIBU-DP is constructed. The transmission signals are digitized. The characteristics of full-distributed, full-digital, and full-open of the FCS covered the shortages which existed in the distributed control system (DCS).Again, with the development of industry, process objective becomes more and more complicated, no-linear, large-delay, and hard to build models. So it is difficult to fulfill the request only by PID control. However, advanced control strategies show strong advantages for resolving these problems in the control system. So the research of advanced control based on PLC is to be a current focus.Finally, the system error was analyzed and the software was designed, includingPLC configuration, PLC program and the system monitoring program. |
