基于PLC的水箱温度控制系统摘要本文研究的是可编程控制器在水箱恒温控制系统中的应用，水箱恒温控制装置主要用来完成对水箱中液体的液位和温度检测，并对温度参数进行调节。系统中温度控制是一个非常重要的部分。通过铂热电阻对温度进行测量，将测量到的温度传到PLC中。PLC对采集到的温度值与给定值进行比较，经过PID运算后，调节双向晶闸管在设定周期内通断时间的比例，改变加热丝中电流大小及加热时间，以完成对温度的控制要求。本系统硬件部分主要由CPU224、EM235、双向晶闸管等组成；软件部分主要由PID控制来完成。关键词：PLCCPU224EM235双向晶闸管PID控制IAbstractInthispaper,istheprogrammablecontrollerinthewatertanktemperaturecontrolsystemapplication,watertanktemperaturecontrolsystemismainlyusedtocompletethetankliquidlevelandtemperaturedetection,andadjustthetemperatureparameters.System,temperaturecontrolisaveryimportantpart.ByplatinumRTDtemperaturemeasurementwillbemeasuredinthetemperaturereachedthePLC.PLConthecollectedtemperaturevaluescomparedwithagivenvalue,afteraPIDoperation,theregulatorTriacoffthesetperiodoftimetheratioofchangeinheatingwireinthecurrentsizeandheatingtimetocompletetherighttemperaturecontrolrequirements.ThesystemhardwaremainlybytheCPU224,EM235,bi-directionalthyristoretc.;software,someofthemajorbythePIDcontroltocomplete.Keywords:PLCCPU224EM235TriacPIDControlII目录1.前言.........................................................................................................................................................................11.1恒温系统应用..................................................................................................................................................11.2PLC的结构......................................................................................................................................................11.2.1中央处理单元(CPU)................................................................................................................................11.2.2存储器......................................................................................................................................................11.2.3电源..........................................................................................................................................................21.3PLC的工作原理..............................................................................................................................................21.3.1PLC的基本工作原理..............................................................................................................................21.3.2PLC编程方式.........................................................................................................................................31.4PLC的控制系统发展趋势..............................................................................................................................31.5PLC控制系统的构成设计原则及步骤..........................................................................................................41.5.1PLC的设计原则......................................................................................................................................41.5.2PLC的设计步骤......................................................................................................................................52硬件设计..........................
