毕业设计（论文）-PLC高、低压无塔供水系统.doc

摘 要 本系统的主要内容是将PLC控制网络技术、计算机控制技术应用于工程实践中，以人们的生活用水、消防高压用水为被控对象，将PLC控制技术、计算机控制技术、自动化技术融合于系统中。该统改变了以前生活和消防两套独立供水的模式，同时克服了传统有塔有箱供水方式的缺点，是一种节能、占地少、投资小、系统安全可靠、维护和管理方便的供水控制系统。 本系统基于变频器内置Pm调节系统，以管网的压力变送器压力信号作为反馈信号，由上位机发出的当前状态作为给定输出，调节生活供水压力使其保持低恒压状态;当火灾发时，调节系统管网压力为高恒压状态。同时，系统设计考虑了夜间低流量状态下，水泵机组停运行，由气压罐进行低流量供水，保证了系统避免频繁启停，同时保证水泵的高效运行。 基于供水系统和消防系统构筑了一个DCS集散系统。2台变频器和PLC作为下位机设备，工控机作为上位机集中控制，上下位机之间通过通讯，把系统当前状态、当前给定通过上位机来综合判断，并通过上位机以汉化界面形式予以显示，而下位机的变频部分则实现管网的恒压功能，PLC实现4台水泵机组逻辑控制和定期巡检，及部分故障综合报告。 关键词：生活和消防用水；恒压；通讯 Abstract The main content of this thesis is the practice for using programmable logic controller(PLC) and computer controller. The system combines the PLC, computer controller, and automatic technology in order to control the living water supply and fire fighting water supply. The system is with the virtue of energy saving, smaller volume, lower investment, higher reliability and easier for maintenance and manage compared with the traditional water supply method with tower and bank. The system is based on the inner PID regulate function of frequency converter to regulate the living water stress with low constant stress, and the stress signal is sensed by the stress translator as feedback signal and the construction is sent by the computer as the given signal. The water stress is regulated to high constant stress when the fire happens. The system is also designed to supply the water by air pot with low flux at night when the demand of water decreases and pump is stopped. The design avoids the system working and pausing frequently and assures the system working with high efficiency A distributed control system is built based on the water supplying system and the fire fighting system. Two ABB frequency converters and a Siemens programmable logic controller(PLC) are with the lower-level computer and Industry computer are with the host computer. The communication between with the host computer and low-level computer not only translate the system condition, but also send the