dhrnubi西门子PLC四层电梯毕业论文.docVIP

^ | You have to believe, there is a way. The ancients said: the kingdom of heaven is trying to enter. Only when the reluctant step by step to go to it s time, must be managed to get one step down, only have struggled to achieve it. -- Guo Ge Tech 长沙理工大学 学生毕业设计（论文） 题 目： Along with sciences and technologys development, the recent years, our countrys elevator production technology obtained the rapidly expand. Some elevator factory unceasingly is also improving the design, the revision craft. The renewal production renewals elevator, the elevator mainly divides into the mechanical system and the control system two major parts, along with the automatic control theory and microelectronic technologys development, elevators dragging way and the control method has had the very big change, the exchange velocity modulation is the current elevator dragging main development direction. At present the lift control system mainly has three control modes: Following electric circuit control system (“early installment elevator many black-white control system), PLC control system, microcomputer control system. Because the black-white control system the failure rate is high, the reliability is bad, control mode not nimble as well as consumed power big and so on shortcomings, at present has been eliminated gradually. Although the microcomputer control system has the strong function in the intelligent control aspect, but also has the interference rejection to be bad, the system design is complex, generally the servicemen master flaws with difficulty and so on its service technology. But PLC control system, because moves the reliability to be high, the use service is convenient, anti-jamming, the design and the debugging cycle is short and so on merits, time is taken seriously the people and so on merits, have become present use most control modes in the lift control system, at present also widely use in the tradition black-white control systems technological transformations. in