摘 要 随着我国社会经济的发展，住房制度改革的不断深入，人们生活水平的不断提高，城市中各类小区建设发展十分迅速，同时也对小区的基础设施建设提出了更高的要求。小区供水系统的建设是其中的一个重要方面，供水的经济性、可靠性、稳定性直接影响到小区住户的正常生活和工作，也直接体现了小区物业管理水平的高低。传统的恒速泵加压供水、水塔高位水箱供水、气压罐供水等供水方式普遍不同程度的存在效率低、可靠性差、自动化程度不高等缺点，难以满足当前经济生活的需要。本论文针对住宅小区的供水要求，设计了一套由PLC、变频器、远传压力表、多台水泵机组、计算机、通信模块等主要设备构成的全自动变频恒压供水及其远程监控系统，具有全自动变频恒压运行、自动工频运行、远程手动控制和现场手动控制等功能。系统有效地解决了传统供水方式中存在的问题，并具有多种辅助功能，增强了系统的可靠性。并和计算机实现了有机的结合，提升了系统的总体性能。基于水泵供水流量和水泵转速的三次方成正比，论文分析了采取变频调速方式实现恒压供水相对于传统的阀门控制恒压供水方式的节能机理。通过对变频器内置P模块参数的预置，利用远传压力表的水压反馈量，构成闭环系统，根据用水量的变化，采取PD调节方式，在全流量范围内利用变频泵的连续调节和工频泵的分级调节相结合，实现恒压供水且有效节能。论文论述了采用多泵并联供水方案的合理性，分析了多泵供水方式的各种供水状态及转换条件，分析了电机由变频转工频运行方式的切换过程及存在的问题。给出了实现有效状态循环转换控制的电气设计方案和PLC控制程序设计方案。通过对计算机和PLC之间通信协议的研究，完成了上、下位机的通信设置，给出了计算机监控程序编写方法，通过通信模块实现了对供水系统的远程监控和故障报警。关键词：恒压供水；PLC；变频调速AbstractAlong with the development of the socioeconomy of our count，the housing system is going deep into reforms，and peoples living standard is being improvedAt the same time，in the city，each kind of subdistrict constmction is developing very quickly，which puts forrward higher requirement for the infrastrucn construction of sub-districtAnd the construction of sub-district water supply system is an important aspect in whichThe reliability，stability and economy of water supply directly affects subdistrict Households nomal life and work,and also embodies the difference in the level of sub-district property managementThe traditional means of water supply such as the pump pressurization water supply at constant speed，water tower of upper cistem，the jaretc are hard to satisfy the needs of current economic life， because low efficiency，reliability and automation level are all commonly existing in these meansAccording to the requirement of water supply in a abiding place，a set of automatic system of constant pressure water supply by using variable frequency and remote monitofing and comrolling，wrhich is composed of PLC，transducer,pressure sensor,pumps and electromotors，computer and device of communication is designed to that endThis set of system has the functions like automatic constant pressure operation by using variable frequency，automatic work frequency operation，and the function of long-range conrol by hand and the on-thespot control by hand etcThe system has solved efficiently the problem existing in the traditional way of water supply,which has various supplementary functions to strengthen the reliabilityThe system has an organic combination with computer and promotes the systematic overall performanceBased on that the three side of the pump water delivery rate and the pump rotational speed become direct ratio，the paper analyses the mechanism of energy saving that the way of water supply by using the method of variable velocity variable frequency is superior to the traditional way of constant pressure water supply controlled by valve Setting up in advance the parameter of the PH modular built-in the transducer,a system of closed circuit using the feedback of hydraulic pressure of farbiograhy pressure table has formedAccording to the change of water consumption,with PID，in the sphere of whole rate of now combining the constant regulation of the pump offrequency conversion with the work frequency pump grade regulation，the system of closed circuit can realize the constant pressure water supply and save energy efficiently This paper discusses the reasonability of water supply scheme with much pump parallel connection，and analyses the conversion condition and the various states of water supply of the much pump way of water supply as well as the switch process and the problem of a generator from variable frequency operation mode to work frequency operation mode This paper has also given the electrical design scheme and PLC controlling program scheme that realizes effective state circulating conversion control By researching the communication agreement between the computer and PLC，this paper has finished setting up the communication between upper and lower computer,and also has described the method to compile computer monitoring program to realize the longrange monitoring and fault reporting for water supply system through communication modular Key words：Constant pressurewater-supply；PLC；Variable velocity variable frequency； Constant pressurewater-supplyKey words：Constant presrewater supply；PLC；Variable Velocity Variable fequency；Constant pressurewater-supply目 录摘 要1Abstract2第一章 绪 论61.1 课题背景及意义61.2 国内外变频调速技术的发展与现状71.3 可编程控制器(PLC)的特点及应用81.4 变频恒压供水系统特点及其安全性讨论131.5 本课题的主要研究内容14第2章 系统的理论分析及方案的确定152.1 变频恒压供水系统理论分析152.2.1 变频恒压供水系统节能原理152.1.2 变频恒压控制的理论模型172.1.3 变频恒压供水系统的近似数学模型1822 变频恒压供水系统控制方案的确定182.2.1 供水系统的控制流程及其控制流程图182.2.2 供水系统中水泵切换条件分析262.3 本章小结29第三章 变频恒压供水系统的硬件设计303.1 系统主要配置的选型303.1.1 水泵机组的选型303.1.2 变频器的选型313.1.3 PLC及其扩展模块的选型333.1.4 压力变送器及数显仪的选型343.1.5 继电器，软启动器