变频恒压供水控制系统地研究与设计.doc

摘要 随着社会主义市场经济的发展，人们对供水质量和供水系统可靠性的要求不断提高；再加上目前能源紧缺，利用先进的自动化技术、控制技术以及通讯技术，设计高性能、高节能、能适应不同领域的恒压供水系统成为必然的趋势 本论文根据中国城市小区的供水要求，设计了一套基于PLC的变频调速恒压供水系统。变频恒压供水系统由可编程控制器、变频器、水泵机组、压力传感器、工控机等构成。 本文设计系统包含三台水泵电机，它们组成变频循环运行方式。采用变频器实现对三相水泵电机的软启动和变频调速。压力传感器检测当前水压信号，送入PLC与设定值比较后进行PID运算，从而控制变频器的输出电压和频率，进而改变水泵电机的转速来改变供水量，最终保持管网压力稳定在设定值附近。通过工控机与PLC的连接，采用组态软件完成系统监控，实现了运行状态动态显示及数据、报警的查询。 关键字：变频调速；恒压供水；PLC Abstract Along with the development of the socialist market economy, the people of the requirement of increasing the quality of water supply and water supply system reliability;Combined with the current energy shortage, the use of advanced automation technology, control technology and communication technology, the design of high performance, high energy saving, can adapt to different areas of constant pressure water supply system become inevitable trend According to the requirements of the Chinese urban community water supply, this paper designed a set of frequency conversion velocity modulation constant pressure water supply system based on PLC.Frequency constant pressure water supply system by programmable controller, inverter, pump, pressure sensors, industrial control, etc. This system contains three water pump motor, their operation mode of frequency conversion cycle.Using frequency converter of four phase water pump motor soft start and frequency control of motor speed.The current hydraulic pressure sensor signal, into after compared with the set value of PID of PLC, frequency converter to control the output voltage and frequency, and change the water pump motor speed to change water supply, eventually maintain stability of the pipe network pressure near the set point.Through the industrial computer and PLC connection, using configuration software to complete the system monitoring, the dynamic running state display and data.