工控培训教程、手册合集如何用s7-200实现modbus通信

Service& SIMATICS7-200,CPU 说明参数设置步骤：1,2,3,4,5,1516。要求要使用Modbus协议必须先获得并在STEP7Micro/Win中安装指令库(条目 Modbus主站协议只被STEP7Micro/WinV4.0SP5及其以上版本支持。.硬件设置o)1Micro/WINPGPCCPU0Profibus缆进行连接（电3，3，8，8->01）M(26KB图参数匹配"MBUS_INIT"and"MBUS_SLAVE"。"(40KB图MBUS参意选0=PPI,1200,2400,4800,9600,19200,38400,57600,STEP7Micro/WIN帮助："MODBUS主站执MBUS_MSG时的错误代码"参参意选0=读1=wwwPLCworld0128Q0.0w

1)STEP7Micro/WIN帮助："MODBUSMBUS_MSG时的错误代码。参意选0=PPI,1200,2400,4800,9600,19200,38400,57600,参意选库的地再被其它程序所使用(主站侧:"DataPtr"+"Count"从站侧："HoldStart"+"MaxHold")。图co.

(137KBwwwPLCworld保持寄存器值的传输见图.04。保持寄存器是以字为单位传输的，它与从站的V区地址对应。可以按下面公式计算从站的V区目标指针：2*(Addr-40001)+HoldStart=2*(40002-40001)+&VB0="MaxHold>=Addr-40001+Count=40002-40001+1=(38KBFig. )条目号 日期:2008-05-HowHowdoyouimplementMODBUScommunicationwithS7-Displaypart SIMATICS7-200,CPU TakingthefollowingexampleyoucansetupasimpleMODBUSmaster-slavecommunicationbetweentwoS7-200CPUs.TheexampleconcernstheMODBUSfunctioncode6(Writetoslave-holdingregister)andcanbeconsideredasabasisforstep-by-stepchangingoftheparametersfortheotherfunctioncodessupported:1,2,3,4,5,15and16.TooperatetheMODBUSprotocolyoumustfirstprocureandinstallfirsttheSTEP7Micro/WINcommandlibrary,thenSTEP7Micro/WIN(EntryID TheMODBUS-MasterprotocolissupportedonlyfromSTEP7Micro/WINV4.0ServicePack51.Hardware2.Parameter3.Memoryaddressingforthe4.Holdingregistervalue9M.wHardware ww9M.wTheexampleissetupforaMODBUScommunicationbetweenthePorts0oftwoS7-200CPUs(preferablyeachwith2communicationinterfaces).OnthemastersideitwouldalsobepossibletoselectPort1withthecorrespondinglibraryblockselection"MBUS_CTRL_P1"and"MBUS_MSG_P1".Port1isconnectedineachcasewithaPCorPGwiththeMicro/WINsoftware.CommunicationbetweentheCPUsviaPort0ismadeviaaPROFIBUScable(serialconnectionofPins3,3,7and8->seeFig.01).Inaddition,youmustmakesurethattheencoderground(M)is(26KBFig.ForMODBUScommunication,onthemastersideyouneedlibraryblocks"MBUSCTRL"and"MBUS_MSG",and"MBUS_INIT"and"MBUS_SLAVE"ontheslaveside.InMicro/WINyoucreateanewprojectforthemasterandtheslavewiththenetworksandparametersshowninFig.02.Hereyoumustmakesurethatthe"Baud"and"Parity"parametersareidenticalandthatthe"Slave"addressofthe"MBUS_MSG"blockmatchesthe"Addr"parameterofthe"MBUS_INIT"block(seeFig.02).ThebaudratesettingforthePort0interfaceinthe"Systemdatablock"viewinMicro/WINisirrelevantfortheMODBUSprotocol("Mode"="1").(40KBFig.Thefollowingtablesdescribethemeaningsandselectionoptionsofthelibraryblock0=PPI,Transmissionratein1200,2400,4800,9600,19200,38400,0=none,1=odd,umtimeinmsforthe'Finished'ErrorTable1)SeeSTEP7Micro/WINHelp:"ErrorcodesfortheexecutionoftheMODBUSmasteroperationw.91HMI.oBUS wwwPLCworldSlave"Read"or0=read,MOBDUSinitial0..128=digitaloutputsQ0.0..Q15.710001..10128=digitalinputsI0.0..30001..30092=oginputsAIW0..40001..49999=holdingregisterNumberofbits(0xxxx,1xxxx)/words(3xxxx,Pointertostartofvariable'Finished'ErrorTable1)SeeSTEP7Micro/WINHelp:"ErrorcodesfortheexecutionoftheMODBUSmasteroperationMBUSMSG"MBUSINIT0=PPI,SlaveTransmissionratein1200,2400,4800,9600,19200,57600,0=none,1=odd,SignalstretchinginNumberofavailabledigitalinputsandNumberof oginputMax.numberofholdingregisterwordPointertothestartoftheholdingregister'Finished'ErrorTable2)The umaddressesthatcanbereallyuseddependsontheCPUtypeusedandits 3)SeeSTEP7Micro/WINHelp:"ErrorcodesfortheexecutionoftheMODBUSslave'Finished'rrorErrorTable3)SeeSTEP7Micro/WINHelp:"ErrorcodesfortheexecutionoftheMODBUSslaveMemoryaddressingfortheAftercompletionoftheprojectsyoumustdefinethememoryforthelibraryintheMicro/WINprogramblockcontainer.Whenreservingmemoryforthelibraries,makesurethattheareaselectedineachcasedoesnotoverlapthevariablememoryareaforthedata(forthemaster:"DataPtr"+"Count"andfortheslave:"HoldStart"+"MaxHold").(137KBFig.HoldingregistervalueAfterloadingtheprojectsintotheappropriateCPUyoucanwritetotheselectedmastervariablememoryareabyactivatingthetablestatusandmonitorontheslaveside.WhenthemasterinputI0.0isactivated,thecontentofvariablewordVW2issenttotheslaveCPUandwrittenheretothevariablewordVW2.ThisholdingregistervaluetransferisshowninFig.Thepointer"DataPtr"representsthestartofthevariablememorytobeThe"Count"parameterspecifiesthenumberofwordstobewrittentotheaddress"Addr"="4xxxx"(holdingregister).Thevariablememoryareaselectedwillbewrittentotheholdingregisterstartaddress"Addr"="40002"("RW"="1").TheholdingregisterworkswordforwordasaplaceholdertotheslavevariablememoryThe"HoldStart"pointerspecifiestheinitialaddressofthevariablememoryequivalenttotheholdingregisterstartaddress40001.Youcancalculatetheslavevariablememorytargetpointerasfollows:2*(Addr-40001)+HoldStart=2*(40002-40001)+&VB0=&VB2Inaddition,youmustmakesurethatthe umnumbero