西门子S7-200 ModBus从站通讯程序

1、本文格式为Word版，下载可任意编辑西门子S7-200 ModBus从站通讯程序 始终看到有些伴侣在问ModBus主从站的通讯问题，今日抽空儿给大家发几篇。 事先申明，我是调用的主从站库，库本身并不是我编写的，我没有那么大的能耐。另外，上位机是用VB编写，VB本身不是很熟，假如有什么错误，请大家海谅。最终，这仅仅只是一个测试程序，假如各位想用到商业方面，还需要各位自己去完善。说明：plc从站，PC作主站，用ModBus协议进行通讯。PC机读取PLCVW区的数据；PC机还读取PLC内部I或者O地址的状态。/以下是PLC程序实现，便利贴出，已转换为STLTITLE=程序解释Network 1 /

2、网络标题/ 在第一个循环周期内初始化Modbus从站协议LD SM0.1CALL SBR3, 1, 12, 9600, 0, 0, 128, 32, 1000, VB0, M10.1, MB11Network 2/ 在每个循环周期内执行Modbus 从站协议LD SM0.0CALL SBR1, M10.2, MB12Network 3LD SM0.0MOVW AIW0, VW100/I +54, VW100MOVW AIW2, VW102/I +54, VW102MOVW AIW4, VW104/I +54, VW104MOVW AIW6, VW106/I +54, VW106Network

3、4LD SM0.0= Q0.0Network 5LD I0.0= Q0.1Network 6LD I0.1= Q0.2/以下是VB源码Option ExplicitPrivate Declare Function GetTickCount Lib "kernel32" () As LongDim x1Dim p11, p12, p13, p14, p15, p16, p17, p18Function CRC16(data() As Byte) As StringDim CRC16Lo As Byte, CRC16Hi As Byte 'CRC寄存器Dim CL As

4、 Byte, CH As Byte '多项式码HA001Dim SaveHi As Byte, SaveLo As ByteDim i As IntegerDim Flag As IntegerCRC16Lo = HFFCRC16Hi = HFFCL = H1CH = HA0For i = 0 To UBound(data)CRC16Lo = CRC16Lo Xor data(i) '每一个数据与CRC寄存器进行异或For Flag = 0 To 7SaveHi = CRC16HiSaveLo = CRC16LoCRC16Hi = CRC16Hi 2 '高位右移一位CR

5、C16Lo = CRC16Lo 2 '低位右移一位If (SaveHi And H1) = H1) Then '假如高位字节最终一位为1CRC16Lo = CRC16Lo Or H80 '则低位字节右移后前面补1End If '否则自动补0If (SaveLo And H1) = H1) Then '假如LSB为1，则与多项式码进行异或CRC16Hi = CRC16Hi Xor CHCRC16Lo = CRC16Lo Xor CLEnd IfNext FlagNext iDim ReturnData(1) As ByteReturnData(0) = C

6、RC16Hi 'CRC高位ReturnData(1) = CRC16Lo 'CRC低位CRC16 = ReturnDataEnd FunctionPrivate Sub About_Click()frmAbout.ShowEnd SubPrivate Sub Form_Load() '初始化Timer1.Enabled = False '定时器1无效Timer1.Interval = 1000 '定时器1时间为1STimer2.Enabled = True '定时器2有效Timer2.Interval = 1000 '定时器2时间为1ST

7、ext1.Text = ""Text2.Text = ""Text3.Text = ""Text4.Text = ""Text5.Text = ""Text6.Text = ""Text8.Text = ""Text10.Text = ""MSComm1.CommPort = 1 '设定端口号MSComm1.Settings = "9600,n,8,1" '设定通讯波特率MSComm1.InBuffe

8、rSize = 1024 '接收缓冲器大小MSComm1.OutBufferSize = 1024 '输出缓冲器大小MSComm1.InputMode = comInputModeBinary '以二进制传输MSComm1.RThreshold = 1 'MSComm1.SThreshold = 0MSComm1.InputLen = 0 '读取接收缓冲器全部字符MSComm1.OutBufferCount = 0 '清空发送缓冲区MSComm1.InBufferCount = 0 '清空接收缓冲区If MSComm1.PortOpen

9、= False ThenCommand3.Caption = "打开串口"ElseCommand3.Caption = "关闭串口"End IfEnd SubPrivate Sub Command1_Click()Timer1.Enabled = TrueEnd SubPrivate Sub Command2_Click() '退出程序，定时器1无效Timer1.Enabled = FalseClsUnload MeEnd SubPrivate Sub Command3_Click()On Error Resume NextIf MSComm1.

10、PortOpen = False ThenMSComm1.PortOpen = TrueElseMSComm1.PortOpen = FalseEnd IfIf MSComm1.PortOpen Then '打开关闭按钮显示文字Command3.Caption = "关闭串口"ElseCommand3.Caption = "打开串口"End IfIf Err Then '打开串口失败，则显示出错信息MsgBox Error$, 48, "错误信息"Exit SubEnd IfEnd SubPrivate Sub Tim

11、er1_Timer() '读V存储区数据Dim CRC() As ByteDim FGetData As StringDim aa() As ByteDim s As String Dim str As String Dim i As IntegerDim bb, cc As StringReDim aa(5) As Byte '定义动态数组aa(0) = HCaa(1) = H3aa(2) = H0aa(3) = H32aa(4) = H0aa(5) = H4CRC = CRC16(aa)str = CRCs = ""For i = 1 To LenB(s

12、tr)s = s + Hex(AscB(MidB(str, i, 1)Next ibb = Right(s, 2)cc = Mid(s, 1, 2)If Len(s) 4 Thencc = Mid(s, 1, 1)End IfReDim Preserve aa(0 To 7) As Byteaa(6) = Val("H" bb)aa(7) = Val("H" cc)MSComm1.OutBufferCount = 0 '清空输出寄存器MSComm1.Output = aaFGetData = ReceiveDataText5.Text = FGe

13、tDatap11 = Val("H" Mid(FGetData, 7, 4)p12 = Val("H" Mid(FGetData, 11, 4)p13 = Val("H" Mid(FGetData, 15, 4)p14 = Val("H" Mid(FGetData, 19, 4)End SubPrivate Sub Command4_Click() 'I状态Dim CRC() As ByteDim FGetData As StringDim aa() As ByteDim s As StringDim st

14、r As StringDim i As IntegerDim bb, cc As StringReDim aa(5) As Byte '定义动态数组aa(0) = HCaa(1) = H2aa(2) = H0aa(3) = H0aa(4) = H0aa(5) = H1CRC = CRC16(aa)str = CRCs = ""For i = 1 To LenB(str)s = s + Hex(AscB(MidB(str, i, 1)Next ibb = Right(s, 2)cc = Mid(s, 1, 2)If Len(s) 4 Thencc = Mid(s, 1

15、, 1)End IfReDim Preserve aa(0 To 7) As Byteaa(6) = Val("H" bb)aa(7) = Val("H" cc)MSComm1.OutBufferCount = 0 '清空输出寄存器MSComm1.Output = aaFGetData = IReceiveDatap17 = Val("H" Mid(FGetData, 7, 2)p18 = Val("H" Mid(FGetData, 9, 2)End SubPrivate Sub Command5_Clic

16、k() 'Q状态Dim CRC() As ByteDim FGetData As StringDim aa() As ByteDim s As StringDim str As StringDim i As IntegerDim bb, cc As StringReDim aa(5) As Byte '定义动态数组aa(0) = HCaa(1) = H1aa(2) = H0aa(3) = H0aa(4) = H0aa(5) = H1CRC = CRC16(aa)str = CRCs = ""For i = 1 To LenB(str)s = s + Hex(

17、AscB(MidB(str, i, 1)Next ibb = Right(s, 2)cc = Mid(s, 1, 2)If Len(s) 4 Thencc = Mid(s, 1, 1)End IfReDim Preserve aa(0 To 7) As Byteaa(6) = Val("H" bb)aa(7) = Val("H" cc)MSComm1.OutBufferCount = 0 '清空输出寄存器MSComm1.Output = aaFGetData = QReceiveDatap15 = Val("H" Mid(FG

18、etData, 7, 2)p16 = Val("H" Mid(FGetData, 9, 2)End SubPrivate Function ReceiveData() As String '返回V存储器区数据Dim FGetData As StringDim t1 As LongDim av As VariantDim i As IntegerDim ReDataLen As IntegerFGetData = ""t1 = GetTickCount() '取时间，做延时用Do '循环等待接收数据DoEventsIf MSComm

19、1.InBufferCount 0 Then '串口有数据了ReDataLen = MSComm1.InBufferCount '取数据长度av = MSComm1.Input '将串口数据取出来For i = 0 To ReDataLen - 1FGetData = FGetData Right("00" Hex(av(i), 2)Next iEnd IfIf Len(FGetData) = 6 ThenIf Len(FGetData) Val("H" Mid(FGetData, 5, 2) * 2 + 8 ThenReceiv

20、eData = FGetDataExit FunctionEnd IfEnd IfIf GetTickCount - t1 2000 Then '2秒没收完就不收了ReceiveData = ""Exit FunctionEnd IfLoopEnd FunctionPrivate Function IReceiveData() As String '反回I状态Dim FGetData As StringDim t1 As LongDim av As VariantDim i As IntegerDim ReDataLen As IntegerFGetData

21、 = ""t1 = GetTickCount() '取时间，做延时用Do '循环等待接收数据DoEventsIf MSComm1.InBufferCount 0 Then '串口有数据了ReDataLen = MSComm1.InBufferCount '取数据长度 av = MSComm1.Input '将串口数据取出来 For i = 0 To ReDataLen - 1FGetData = FGetData Right("00" Hex(av(i), 2)Next iEnd IfIf Len(FGetData

22、) = 6 ThenIf Len(FGetData) Val("H" Mid(FGetData, 5, 2) * 2 + 8 ThenIReceiveData = FGetDataExit FunctionEnd IfEnd IfIf GetTickCount - t1 2000 Then '2秒没收完就不收了IReceiveData = ""Exit FunctionEnd IfLoopEnd FunctionPrivate Function QReceiveData() As String '反回Q状态Dim FGetData As

23、StringDim t1 As LongDim av As VariantDim i As IntegerDim ReDataLen As IntegerFGetData = ""t1 = GetTickCount() '取时间，做延时用Do '循环等待接收数据DoEventsIf MSComm1.InBufferCount 0 Then '串口有数据了ReDataLen = MSComm1.InBufferCount '取数据长度av = MSComm1.Input '将串口数据取出来For i = 0 To ReDataLen - 1FGetData = FGetData Right(&q