Rh Vacuum Refining The Control System Of Plc Program Design

The process of RH and the electro-mechanic characteristics of the main process devices are described first. Then the control requirements of the process are analyzed in detail. The thesis gives deep studies on how to apply modern control technologies, computer network technologies, field bus technologies, electrical drive technologies, etc. in the control system design in order to make the RH control system come up to the advanced world level. And RH control system structure, based on high speed Ethernet, field bus, programmable logic controllers and industrial PCs, is proposed.In this thesis, the theory of"air bubble pumps"in circulation of liquid steel, the theory of vacuum degassing, the theory of vacuum deoxidization, the theory of vacuum decarburization, the foundation of thermodynamics and dynamics in vacuum degassing are analyzed. These basic theories are the foundation of function implementation in the control system.The simatic S7-400 PLC is the controller in this basic automation control system. The PLC's program for ladle car transferring control , ladle lifting control, lifting gas control, top lance lifting and heating control, vacuum pressure and vacuum pumps control, alloy addition control, wire feeding control are designed in detail. The operator can operate and monitor the process devices on HMI in the central control room.After this control system puts into operation, its function inspection approval has been examined and confirmed by SMS MEVAC GmbH and Panzhihua Iron and Steel Co. The performance indexes of control system have achieved the design requirements. The control system runs so far, it is reliable and steady.