| Considering the problems like low level,single variety and supply-demand contradiction existing in domestic plate products, the plate enterprises plan to improve quality, expand high-performance and strengthen international competition ability of their products with quenching treatment process.As the important equipment of heat treatment process, roller quenching machine has the advantages of fast cooling rate, uniform surface hardening, and it has become the first choice of quenching equipment in plate plant at present.Based on plate roller quenching machine project of Shanxi TISCO Linfen Iron & Steel Co.Ltd, the automation system of the first roller quenching machine whose total intellectual property belongs to China is developed in spite of the difficulties such as complex process, cooling control proceeding and so on.In this paper, the quench control cooling of plate is two-grade computer control system which includes basic automatic control system and process computer control system. The automatic control system is realized by SIEMENS S7-400 PLC.At the same time, PROFIBUS-DP technique is applied to process communication between PLC and MM440.It simples system structure, strengthens system reliability and stability, improves control precision. Whole automatic control includes valve on/off, plate tracking, water flow and water pressure control with PID, interlock control, data acquisition, data communication of process computers.An on-line monitoring and control platform completed by using WINCC software can realize fault alarming and table printing, dynamic process parameters displaying of the whole heat-treatment line in real time.It supplies good conditions for process optimization. In the other hand, process automation/HMI and basic automation are communicated by the Ethernet and all operator and monitoring interfaces are realized by WINCC.In the process automation part, the process control policy and module functions of the quenching machine process control system are narrated.During debugging processing, it is very difficult to expect disturbance by kinds of noise source in spot. Some input signal can cause fault operation, system disorder and even great loss.Therefore, it seems important to eliminate interference signal and sharpen system anti-interference ability with signal filtering programme.In addition, the controlled variables are too many, especially water control requires high precision,in addition,the domestic production equipment is mostly imported,there is no information to refer. The Simulink software package which MATLAB provides is selected to simulate the PID control and fuzzy control.The simulation result shows the fuzzy control is superior to PID control.The roller quenching machine developed by us has been running for about one year in spot and brings remarkable economic benefit for TISCO Linfen Iron & Steel Co.Ltd. The overall system has high cost-preferment, so the application value of roller quenching machine has much bigger extension space. |
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