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I摘要温度控制系统广泛应用于工业控制领域，如钢铁厂、化工厂、火电厂等锅炉的温度控制系统，电焊机的温度控制系统等。加热炉温度控制在许多领域中得到广泛的应用。这方面的应用大多是基于单片机进行PID控制,然而单片机控制的DDC系统软硬件设计较为复杂,特别是涉及到逻辑控制方面更不是其长处,然而PLC在这方面却是公认的最佳选择。加热炉温度是一个大惯性系统，一般采用PID调节进行控制。随着PLC功能的扩充在许多PLC控制器中都扩充了PID控制功能,因此在逻辑控制与PID控制混合的应用场所中采用PLC控制是较为合理的。本设计是利用西门子S7-200PLC控制加热炉温度的控制系统。首先介绍了温度控制系统的工作原理和系统的组成，然后介绍了西门子S7-200PLC和系统硬件及软件的具体设计过程。关键词：温度控制；PID；温度传感器；可控硅电压调整器IIAbstractTemperaturecontrolsystemhasbeenwidelyusedintheindustrycontrolledfield，asthetemperaturecontrolsystemofboilersandweldingmachinesinsteelworks、chemicalplant、heat-engineplantetc.Heating-stovetemperaturecontrolhasalsobeenappliedwidelyinallkindsoffields.TheapplicationofthisaspectisbasedonSCMwhichismakingthePIDcontrol,yetthehardwareandsoftwaredesignofDDCsystemcontrolledbySCMissomewhatcomplicated,it’snotanadvantageespeciallyrelatedtologiccontrol,howeveritisacceptedasthebestchoicewhenmentionedtoPLC.Thefurnacetemperatureofheating-stoveisalargeinertiasystem，sogenerallyusingPIDadjustingtocontrol.WiththeexpandingofPLCfunction,thecontrolfunctioninmanyPLCcontrollershasbeenexpanded.ThereforeitismorereasonabletoapplyPLCcontrollingintheapplicablefieldswherelogicalcontrolandPIDcontrolblendtogether.ThedesignhasutilizedthecontrolsystemwithwhichSiemensS7-200PLCcontrolthetemperatureheating-stove.Inthefirstplacethispaperpresentstheworkingprinciplesofthetemperaturecontrolsystemandtheelementsofthissystem.ThenitintroducesSiemensS7-200PLCandthespecificdesignproceduresofthehardwareandthesoftware.KeywordsTemperaturecontrolPIDtemperaturepickupSCRVoltageConverterIII目录摘要...........................................................................................................................IAbstract...................................................................................................................II第1章绪论............................................................................................................11.1课题背景及意义...........................................................................................11.2研究的主要内容...........................................................................................11.3系统的设计目标及技术要求.......................................................................11.4控制系统的设计原理...................................................................................21.5技术综述.......................................................................................................2第2章硬件设计....................................................................................................42.1西门子S7-200PLC......................................................................................42.1.1西门子S7-200主要功能模块介绍......................................................42.1.2开关量I/O模块介绍............................................................................52.2温度传感器...................................................................................................52.2.1热电偶....................................................................................................62.2.2热电阻....................................................................................................62.3模拟量输入模块...........................................................................................82.3.1EM231模拟量输入模块........................................................................82.3.2EM232模拟量输出模块......................................................................102.4可控硅电压调整器.....................................................................................112.4.1可控硅电压调整器简介......................................................................112.4.2可控硅电压调整器的主要性能指标..................................................122.4.3双向可控硅交流调压原理..................................................................122.4.4可控硅电压调整器在加热炉中的应用..............................................132.5本章小结.....................................................................................................14第3章炉温PID控制算法.................................................................................153.1PID控制器基本概念..................................................................................153.2PID控制算法数字化处理..........................................................................163.3PID在PLC中的回路指令.........................................................................193.4模拟量采集的数字滤波算法.....................................................................213.5采样周期的选择.........................................................................................233.6PID参数整定..............................................................................................243.7本章小结.....................................................................................................27第4章软件设计..................................................................................................284.1STEP7编程软件简介.................................................................................284.2方案设计思路.............................................................................................284.3程序流程图......