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台达PLC的通讯协议.doc

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台達PLC的通讯协议是公开的，只要对该协议有清楚理解，所有台达产品的通讯问题迎刃而解，下面是协议全文：1.CommunicationInterface:RS-232C2.CommunicationProtocolASCIImode,9600（Baudrate）,EVEN（Parity）,1（Startbit）,1（Stopbit）3.CommunicationDataFrameSTXStartcharacter‘:’（3AH）ADR1Communicationaddress:ADR08-bitaddressconsistsof2ASCIIcodesCMD1Commandcode:CMD08-bitcommandconsistsof2ASCIIcodesDATA（0）Contentsofdata:DATA（1）n´8-bitdataconsistof2nASCIIcodes.……….n£37,maximumof74ASCIIcodesDATA（n-1）LRCCHK1LRCchecksum:LRCCHK08-bitchecksumconsistsof2ASCIIcodesEND1Endcharacter:END0END1=CR（0DH），END0=LF（0AH）nADR（CommunicationAddress）Validcommunicationaddressesareintherangeof0…31.Communicationaddressequalsto0meansbroadcasttoallPLC,thePLCwillreplynormalmessagetothemasterdevice.Forexample,communicationtoPLCwithaddress16decimal:(ADR1,ADR0)=’1’,’0’ð’1’=31H,‘0’=30HnCMD(Commandcode)andDATA(datacharacters)Theformatofdatacharactersdependsonthecommandcode.Forexample,readingcontinuous8wordsformstartingdeviceaddress0614HofPLCwithaddress01H.FieldNameExample(Hex)Heading3ASlaveAddress01Commandcode03StartingAddressHi06StartingAddressLo14NumberofPointsHi00NumberofPointsLo08ErrorCheck(LRC)DANumberofPoints(max)=18（for16bitregister）=9（for32bitregister）Example：ReadingCoilsT20~T27fromslavedevice01PC→PLC“：010306140008DACRLF”PLC→PC“：01031000010002000300040005000600070008B8CRLF”FieldNameExample(Hex)SlaveAddress01Commandcode03BytesCount10DataHi（T20）00DataLo（T20）01DataHi（T21）00DataLo（T21）02DataHi（T22）00DataLo（T22）03DataHi（T23）00DataLo（T23）04DataHi（T24）00DataLo（T24）05DataHi（T25）00DataLo（T25）06DataHi（T26）00DataLo（T26）07DataHi（T27）00DataLo（T27）08ErrorCheck（LRC）C8nLRCCHK（checksum）LRC(LongitudinalRedundancyCheck)iscalculatedbysummingup,module256,thevaluesofthebytesfromADR1tolastdatacharacterthencalculatingthehexadecimalrepresentationofthe2’s-complementnegationofthesum.Forexample,reading1wordformaddress0401HofthePLCwithaddress01HSTX‘：’ADR1‘0’ADR0‘1’CMD1‘0’CMD0‘3’Startingdataaddress‘0’‘4’‘0’‘1’Numberofdata‘0’‘0’‘0’‘1’LRCCHK1‘F’LRCCHK0‘6’END1CREND0LF01H+03H+04H+01H+00+01H=0AHt