Research And Design Of The Third Generation Of MOCVD Control System Based On PLC

GaN and its alloys have a wide application in phtotoelectricity and power devices due to their special capability.MOCVD has become a high-guality technique of GaN and its alloys.So far,productive model MOCVD system equipment is in the blanks at home,mostly are entirely imported abroad.Developing productive MOCVD system equipment with independent intellectual property righting has very important strategic meanings. The project of this paper is supported by Chinese 863 semiconductor illuminating engineerings,according to the characteristics and requirements of xidian Univ.third productive MOCVD system,research and design of MOCVD control system are carried out.MOCVD control system selects Simens S7-300 programmable controller for use as the key controller and Simens WinCC for use as SCADA system. According to the control system'characteristic and the requirment of the material growth,PLC hardware configuration and software program have been completed.The manual and auto programs are designed separately,there are many subprograms of auto program,such as initial,main,step,loop,alarm,multi-channeltime-sharing analog input,analog ramp,analog output,digital output etc.The man-machine location machine controls interfaces has been designed,the new control interface is intuitionistic and visualize,it is easy to operate.MOCVD equipment has already been put into production,the system has been working well and the material grows normally. Practice shows that the control system is strong in anti-interference,dependability is high,have the better precision of control, which meets the MOCVD equipment control system requirements,has guaranteed the material growth. The work launched of this text,have very important meanings to the design and studying of MOCVD control system.The paper pvovides the foundation for the further research and design of productive MOCVD system.