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毕业设计课题名称可编程的中央空调控制系统的设计姓名孙成彩学号201003110736所在系电子电气工程系专业年级P10电气七班指导教师张德迪职称讲师二O一三年四月十四-I-基于PLC的中央空调控制系统设计摘要随着中央空调广泛的应用，空调的舒适性和节能性越来越被人们所重视，由于传统控制系统在控制适宜温度的同时，却消耗了大量的能量，已不能满足现有的节能环保理念。本文重点研究了中央空调冷冻泵机组控制系统，为舒适的生活工作环境及有效节能提供了技术条件。本文首先介绍了中央空调的结构和工作原理，总结了传统中央空调的缺点，即冷冻泵、冷却泵不能自我调节负载，长期处于满负荷运行，造成了极大的能源浪费，随着变频技术日趋成熟，利用变频器、PLC、数模转换模块、温度传感器等器件的有机结合，构成温差闭环自动控制系统，自动调节水泵的输出流量达到节能目的。该系统采用西门子的S7—200PLC作为主控制单元，利用传统PID控制算法，通过西门子MM440变频器控制水泵运转速度，保证系统根据实际负荷的情况调整流量，实现恒温控制，同时又可以节约大量能源。通过对中央空调的理论分析，验证了以出回水温差为根据对其进行变流量控制的可靠性。对变频控制系统进行了设计，为实现温度信号远距离传送，设计了基于USS协议的RS-485总线通讯的网络。通过西门子TD200文本显示器实现人机界面的设计，最后使用MCGS工控组态软件进行了系统的组态设计研究。关键词中央空调；PLC；变频器；PID；RS-485-II-DesignofPLCcontrolsystemforcentralairconditionerabstractCentralairconditioninghasbeenwidelyusedinthemajorshoppingmalls,officebuildingsandotherplaces,thetraditionalcontrolsysteminthecontroloftheappropriatetemperature,butitconsumesalotofenergy.Today,peoplemoreandmoreattentiontothecentralair-conditioningcomfortandenergyconservation,thispaperstudiedcontrolsystemofcentralairconditioningrefrigerationpumpunit,thetechnologyconditionsforcomfortablelivingandworkingenvironmentandeffectiveenergysaving.Firstly,thispaperintroducedthestructureandworkingprincipleofcentralairconditioning,summarizestheshortcomingsofthetraditionalcentralairconditioning,namelychilledwaterpump,coolingpumpcannotbeselfregulatingload,fullloadoperationinthelongterm,resultinginagreatwasteofenergy,withthedevelopmentandmaturityoffrequencyconversiontechnology,usingthecombinationofvariablefrequencyconverter,PLC,digitaltoanalogconversionmodule,temperaturesensors,constitutesasystemoftemperatureclosed-loopautomaticcontrol,automaticallyadjustthepumpoutputflowtoachievethepurposeofenergysaving.ThesystemusesSiemensS7-200PLCasmaincontrolunit,byusingthetraditionalPIDcontrolalgorithm,throughtheSiemensMM440invertercontrolthespeedofthepump,guaranteesystemaccordingtotheactualloadadjustingflowtoachieveconstanttemperaturecontrol,butalsocansavealotofenergy.Basedonthetheoreticalanalysisofthecentralairconditioningsystem,thereliabilityofvariableflowcontrolisverifiedbythedifferenceofthetemperaturedifferencebetweenthewaterandthewater.Thefrequencyconversioncontrolsystemisdesigned,andtheRS-485buscommunicationnetworkbasedonUSSprotocolisdesignedinordertorealizethelong-distancetransmissionoftemperaturesignal.Thedesignofman-machineinterfaceisrealizedthroughtheSIEMENSTD200textdisplay.Finally,theconfigurationdesignofthesystemisdesignedbyusingMCGSconfigurationsoftware.Keywordscentralairconditioning;PLC;frequencyconverter;PID;RS-485-III-基于PLC的中央空调控制系统设计目录摘要.................................................................................................................................I第1章绪论..................................................................................................................11.1课题背景.............................................................................................................11.2中央空调控制的研究现状及发展.....................................................................21.2.1中央空调控制系统的发展..........................................................................21.2.2中央空调变流量控制的发展......................................................................31.3本研究课题的主要工作.....................................................................................4第2章中央空调变流量控制的原理..........................................................................52.1中央空调系统的结构和原理.............................................................................52.1.1概述..............................................................................................................52.1.2制冷原理......................................................................................................52.1.3中央空调系统的构成..................................................................................52.2中央空调变流量控制的原理及特点.................................................................52.2.1变流量空调系统概述..................................................................................52.2.2中央空调变流量控制的实现方式..............................................................72.2.3中央空调系统变流量系统的特点..............................................................92.3电机的软启动原理及应用...............................................................................102.3.1软启动设备介绍........................................................................................102.3.2软启动器的应用场合................................................................................102.3.3软启动器与变频器之间的区别对比........................................................102.4本章小结...........................................................................................................14第3章中央空调控制系统的硬件设计....................................................................153.1变频器的原理...................................................................................................153.2西门子MM440变频器性能介绍....................................................................153.2.1主要特征...................................................................................