vb-modbus代码

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Modbus 通讯协议编程(VB源代码)

最近，本人为了实现电脑与Delta V FD-M变频器通讯，特意用VB6.0编了一个Modbus协议通讯软件。

这只是一个测试版，但Modbus的ASCII协议和RTU协议都已经实现。

现在将源程序上传，希望可以帮助到有需要的朋友，谢谢！另外，假如你觉得有更好的想法，欢迎指教。

如果对本程序有任何意见和建议，也可以一起讨论，共同进步。

大家多多支持俺啊。

附：VB6源程序Option ExplicitPrivate Text1text As StringPrivate RTUCRC As String'串口选择Private Sub Combo1_Click()mPort = Combo1.ListIndex + 1End Sub'数据位改变Private Sub Combo2_Click()Call settingEnd Sub'波特率改变Private Sub Combo3_Click()Call settingEnd Sub'奇偶校验改变Private Sub Combo4_Click()Call settingEnd Sub'停止位改变Private Sub Combo5_Click()Call settingPrivate Sub setting()MSComm1.Settings = CStr(Combo3.Text) & ","& CStr(Combo4.Text) & ","& CStr(C ombo2.Text) _& ","& CStr(Combo5.Text)End Sub'打开关闭串口Private Sub Command1_Click()On Error Resume NextIf MSComm1.PortOpen = False ThenMSComm1.PortOpen = TrueElseMSComm1.PortOpen = FalseEnd IfIf MSComm1.PortOpen Then'打开关闭按钮显示文字及combo1使能Command1.Caption = "关闭串口"Combo1.Enabled = FalseElseCommand1.Caption = "打开串口"Combo1.Enabled = TrueEnd IfIf Err Then'打开串口失败，则显示出错信息MsgBox Error$, 48, "错误信息"Exit SubEnd IfEnd Sub'10转16进制Private Sub Command2_Click(Index As Integer)On Error Resume NextText4.Text = Hex(Text3.Text)If Err Then''则显示出错信息MsgBox Error$, 48, "错误信息"Exit SubEnd If'16转10进制Private Sub Command3_Click()Dim a As Longa = Val("&H"& CStr(Text4.Text))Text3.Text = aEnd Sub'手动串口发送Private Sub Command4_Click()If MSComm1.PortOpen = False ThenMsgBox"请先打开串口", , "错误信息" Exit SubEnd IfCall sentsubEnd Sub'清除接收窗Private Sub Command5_Click()Text2.Text = ""End SubPrivate Sub Command6_Click()Unload MeEnd SubPrivate Sub Command7_Click()On Error Resume NextDim STP As StringSTP = CStr(Chr(2)) & "010001"& CStr(Chr(3)) & "25"MSComm1.Settings = "9600,N,7,2"MSComm1.PortOpen = TrueMSComm1.Output = STPMSComm1.PortOpen = FalseIf Err Then'打开串口失败，则显示出错信息MsgBox Error$, 48, "错误信息"Exit SubEnd IfEnd SubPrivate Sub Command8_Click()On Error Resume NextDim FWD As StringFWD = CStr(Chr(2)) & "010101"& CStr(Chr(3)) & "26" MSComm1.Settings = "9600,N,7,2"MSComm1.PortOpen = TrueMSComm1.Output = FWDMSComm1.PortOpen = FalseIf Err Then'打开串口失败，则显示出错信息MsgBox Error$, 48, "错误信息"Exit SubEnd IfEnd SubPrivate Sub Command9_Click()On Error Resume NextDim REV As StringREV = CStr(Chr(2)) & "010201"& CStr(Chr(3)) & "27" MSComm1.Settings = "9600,N,7,2"MSComm1.PortOpen = TrueMSComm1.Output = REVMSComm1.PortOpen = FalseIf 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 Sub'窗口加载Private Sub Form_Load()Dim d%For d = 1To16Combo1.AddItem ("COM"& CStr(d))NextCombo1.ListIndex = 0Combo2.AddItem "6"Combo2.AddItem "7"Combo2.AddItem "8"Combo2.ListIndex = 2Combo3.AddItem "110" Combo3.AddItem "330" Combo3.AddItem "1200" Combo3.AddItem "2400" Combo3.AddItem "4800" Combo3.AddItem "9600" Combo3.AddItem "19200" Combo3.AddItem "38400" Combo3.AddItem "56000" Combo3.AddItem "57600" Combo3.AddItem "115200" Combo3.ListIndex = 5Combo4.AddItem "n" Combo4.AddItem "o" Combo4.AddItem "e" Combo4.ListIndex = 0Combo5.AddItem "1" Combo5.AddItem "2" Combo5.ListIndex = 0For d = 0To254Combo6.AddItem dNextCombo6.ListIndex = 1Text1.Text = "010*********" Text2.Text = ""Text3.Text = ""Text4.Text = ""Text5.Text = "1000"Text6.Text = "06"Text7.Text = "0"Text8.Text = "1"Option1.value = TrueOption3.value = TrueOption7.value = TrueOption9.value = TrueIf MSComm1.PortOpen = False ThenCommand1.Caption = "打开串口"ElseCommand1.Caption = "关闭串口"End IfEnd Sub'串口接收程序Private Sub MSComm1_OnComm()Dim Hexchr As String, hexstring As String, i As Integer, j As Integer, hexdisp As Str ingIf Option8.value Thenhexstring = MSComm1.Input '十六进制显示i = Len(hexstring)For j = 1To iHexchr = Mid(hexstring, j, 1)If Hex(Asc(Hexchr)) < 16ThenText2.Text = Text2.Text & "0"& Hex(Asc(Hexchr)) & " "ElseText2.Text = Text2.Text & Hex(Asc(Hexchr)) & " "End IfNext jText2.Text = Text2.Text & CStr(Chr(13)) & CStr(Chr(10))ElseText2.Text = Text2.Text & MSComm1.Input & CStr(Chr(13)) & CStr(Chr(10)) 'ASCII 码显示End IfEnd Sub'手动发送选择Private Sub Option1_Click()If Option1.value = True ThenTimer1.Enabled = FalseCommand4.Enabled = TrueElseTimer1.Enabled = TrueCommand4.Enabled = FalseEnd IfEnd Sub'Delta ASCII发送协议Private Sub Option10_Click()Combo6.Enabled = TrueText6.Enabled = TrueText7.Enabled = TrueText8.Enabled = TrueLabel10.Enabled = TrueLabel11.Enabled = TrueLabel12.Enabled = TrueLabel13.Enabled = TrueOption6.Enabled = FalseOption7.Enabled = FalseOption11.value = TrueCombo2.ListIndex = 1Combo5.ListIndex = 1Text1.Enabled = FalseLabel14.Enabled = FalseFrame7.Visible = TrueEnd Sub'自动发送选择 Private Sub Option2_Click()If Option2.value = True ThenTimer1.Enabled = TrueCommand4.Enabled = FalseElseTimer1.Enabled = FalseCommand4.Enabled = TrueEnd IfEnd SubPrivate Sub Option3_Click() 'Non选项 Combo6.Enabled = FalseText6.Enabled = FalseText7.Enabled = FalseText8.Enabled = FalseLabel10.Enabled = FalseLabel11.Enabled = FalseLabel12.Enabled = FalseLabel13.Enabled = FalseOption6.Enabled = TrueOption7.Enabled = TrueCombo2.ListIndex = 2Combo5.ListIndex = 0Text1.Enabled = TrueLabel14.Enabled = TrueFrame7.Visible = FalseEnd SubPrivate Sub Option4_Click() 'ASCII选项 Combo6.Enabled = TrueText6.Enabled = TrueText7.Enabled = TrueText8.Enabled = TrueLabel10.Enabled = TrueLabel11.Enabled = TrueLabel12.Enabled = TrueLabel13.Enabled = TrueOption6.Enabled = FalseOption7.Enabled = FalseCombo2.ListIndex = 1Combo5.ListIndex = 1Text1.Enabled = FalseLabel14.Enabled = FalseFrame7.Visible = FalseEnd SubPrivate Sub Option5_Click() 'RTU选项 Combo6.Enabled = TrueText6.Enabled = TrueText7.Enabled = TrueText8.Enabled = TrueLabel10.Enabled = TrueLabel11.Enabled = TrueLabel12.Enabled = TrueLabel13.Enabled = TrueOption6.Enabled = FalseOption7.Enabled = FalseCombo2.ListIndex = 2Combo5.ListIndex = 1Text1.Enabled = FalseLabel14.Enabled = FalseFrame7.Visible = FalseEnd Sub'发送时间间隔调整输入Private Sub Text5_Change()Dim number As StringDim num As IntegerDim numcyc As Integernum = Len(Text5.Text)For numcyc = 1To numnumber = Mid(Text5.Text, numcyc, 1)Select Case InStr("0123456789", number)Case0MsgBox"输入时间间隔错误，请重新输入", , "错误信息"Exit SubEnd SelectNextTimer1.Interval = Text5.TextEnd Sub'自动发送定时器Private Sub Timer1_Timer()If MSComm1.PortOpen ThenCall sentsubEnd IfEnd Sub'状态刷新定时器Private Sub Timer2_Timer()StatusBar1.Panels(1).Text = "串口选择：" & CStr(Comb o1.Text)StatusBar1.Panels(2).Text = "串口设置：" & CStr(MSC omm1.Settings)StatusBar1.Panels(3).Text = "串口状态：" & CStr(MSC omm1.PortOpen)End Sub'串口发送子程序Private Sub sentsub()Dim optioncase%If Option3.value Then optioncase = 1If Option4.value Then optioncase = 2If Option5.value Then optioncase = 3If Option10.value Then optioncase = 4Select Case optioncaseCase1If Option6.value ThenText1text = Text1.TextCall HexsentElseText1text = Text1.TextCall ASCIIsentEnd IfCase2Call incorporate '将输入的十进制从机地址、命令、资料地址和资料内容合并成字符串Call ASCIIcheckCall ASCIIsentCase3Call incorporate '将输入的十进制从机地址、命令、资料地址和资料内容合并成字符串Call RTUcheckCall HexsentCase4Call incorporate1 '将输入的十进制从机地址、命令、资料地址和资料内容合并成字符串Call deltaASCIICall ASCIIsentEnd SelectEnd Sub'十六进制发送Private Sub Hexsent()Dim hexchrlen%, Hexchr As String, hexcyc%, hexmid As Byte, hexmiddle As String Dim hexchrgroup() As Byte, i As Integerhexchrlen = Len(Text1text)For hexcyc = 1To hexchrlen '检查Text1文本框内数值是否合适Hexchr = Mid(Text1text, hexcyc, 1)If InStr("0123456789ABCDEFabcdef", Hexchr) = 0ThenMsgBox"无效的数值，请重新输入", , "错误信息" Exit SubEnd IfNextReDim hexchrgroup(1To hexchrlen \ 2) As ByteFor hexcyc = 1To hexchrlen Step2'将文本框内数值分成两个、两个i = i + 1Hexchr = Mid(Text1text, hexcyc, 2)hexmid = Val("&H"& CStr(Hexchr))hexchrgroup(i) = hexmid'MSComm1.Output = CStr(hexmid)NextMSComm1.Output = hexchrgroupEnd Sub'ASC码发送Private Sub ASCIIsent()MSComm1.Output = Text1textEnd Sub'ASC校验,此段程序计算出LRC校验值，并加上字头和字尾Private Sub ASCIIcheck()Dim a%, b%, chrnum%, Lrcbyte As StringDim checksum%, char%, AscLrc%, Lrc%chrnum = Len(Text1text)For a = 1To chrnum Step2char= Val("&H"& CStr(Mid(Text1text, a, 2))) '两个两个的取字符checksum = checksum + char'全部加起来NextAscLrc = checksum Mod&H100 '取255的余数Lrc = (&HFF - AscLrc) + 1'取二次补If Lrc < 16Then'此段程序是判断Hex(lrc)是否是一位数，Lrcbyte = "0"+ CStr(Hex(Lrc)) '如果是的话，前面加0；否则不加零ElseLrcbyte = CStr(Hex(Lrc))End IfText1text = CStr(Chr(58)) & CStr(Text1text) & Lrcbyte & CStr(Chr(13)) & CStr(Chr(1 0))End Sub'DeltaASCII校验,此段程序计算出LRC校验值，并加上字头和字尾Private Sub deltaASCII()Dim a%, b%, chrnum%, Lrcbyte As StringDim checksum%, char%, Lrc%chrnum = Len(Text1text)For a = 1To chrnumchar= Asc(Mid(Text1text, a, 1)) '两个两个的取字符 checksum = checksum + char'全部加起来NextLrc = (checksum + &H3) Mod&H100 '取255的余数 If Lrc < 16Then'此段程序是判断Hex(lrc)是否是一位数，Lrcbyte = "0"+ CStr(Hex(Lrc)) '如果是的话，前面加0；否则不加零ElseLrcbyte = CStr(Hex(Lrc))End IfText1text = CStr(Chr(2)) & CStr(Text1text) & CStr(Chr(3)) & LrcbyteEnd Sub'RTU校验Private Sub RTUcheck()Dim CRC() As ByteDim d(5) As ByteDim string1 As StringDim j As Integer, chrlength As Integer, temp As Stringstring1 = Text1textchrlength = Len(string1)For j = 0To chrlength / 2- 1temp = Mid(string1, j * 2+ 1, 2)d(j) = Val("&H"& temp)NextRTUCRC = CRC16(d) '调用CRC16计算函数, CRC(0)为高位, CRC(1)为低位Text1text = Text1text & RTUCRCEnd SubPrivate Sub incorporate() '将输入的十进制从机地址、命令、资料地址和资料内容合并成字符串Dim wholechar As String, wc%, wcyc%, wchar As StringDim SID As String, Cmd As String, InfoAdd As String, data As StringDim SIDnum%, Cmdnum%, InfoAddNum%, Datanum%On Error Resume Nextwholechar = CStr(Combo6.Text) & CStr(Text6.Text) & CStr(Text7.Text) & CStr(Text8.T ext)wc = Len(wholechar)For wcyc = 1To wcwchar = Mid(wholechar, wcyc, 1)If InStr("0123456789", wchar) = 0ThenMsgBox"输入错误，请重新输入", , "错误提示"Exit SubEnd IfNextSIDnum = Len(CStr(Hex(Combo6.Text)))Select Case SIDnumExit SubCase1SID = "0"& CStr(Hex(Combo6.Text)) Case2SID = CStr(Hex(Combo6.Text))End SelectCmdnum = Len(CStr(Hex(Text6.Text))) Select Case CmdnumCase0Exit SubCase1Cmd = "0"& CStr(Hex(Text6.Text)) Case1Cmd = CStr(Hex(Text6.Text))End SelectInfoAddNum = Len(CStr(Hex(Text7.Text))) Select Case InfoAddNumCase0Exit SubCase1InfoAdd = "000"& CStr(Hex(Text7.Text)) Case2InfoAdd = "00"& CStr(Hex(Text7.Text)) Case3InfoAdd = "0"& CStr(Hex(Text7.Text)) Case4InfoAdd = CStr(Hex(Text7.Text))End SelectDatanum = Len(CStr(Hex(Text8.Text))) Select Case DatanumCase0Exit Subdata = "000"& CStr(Hex(Text8.Text))Case2data = "00"& CStr(Hex(Text8.Text))Case3data = "0"& CStr(Hex(Text8.Text))Case4data = CStr(Hex(Text8.Text))End SelectIf Err Then'显示出错信息MsgBox Error$, 48, "错误信息"Exit SubEnd IfText1text = CStr(SID) & CStr(Cmd) & CStr(InfoAdd) & CStr(data)End SubPrivate Sub incorporate1() '将输入的十进制从机地址、命令、资料地址和资料内容合并成字符串Dim wholechar As String, wc%, wcyc%, wchar As StringDim SID As String, Cmd As String, InfoAdd As String, data As StringDim SIDnum%, Cmdnum%, InfoAddNum%, Datanum%On Error Resume Nextwholechar = CStr(Combo6.Text) & CStr(Text7.Text) & CStr(Text8.Text)wc = Len(wholechar)For wcyc = 1To wcwchar = Mid(wholechar, wcyc, 1)If InStr("0123456789", wchar) = 0ThenMsgBox"输入错误，请重新输入", , "错误提示"Exit SubEnd IfNextSIDnum = Len(CStr(Hex(Combo6.Text)))Select Case SIDnumCase0Case1SID = "0"& CStr(Hex(Combo6.Text)) Case2SID = CStr(Hex(Combo6.Text))End Select'Cmdnum = Len(CStr(Hex(Text6.Text)))'Select Case Cmdnum'Case 0' Exit Sub'Case 1' Cmd = "0" & CStr(Hex(Text6.Text))'Case 1' Cmd = CStr(Hex(Text6.Text))'End SelectInfoAddNum = Len(CStr(Hex(Text7.Text))) Select Case InfoAddNumCase0Exit SubCase1InfoAdd = "0"& CStr(Hex(Text7.Text)) Case2InfoAdd = CStr(Hex(Text7.Text))End SelectDatanum = Len(CStr(Hex(Text8.Text))) Select Case DatanumCase0Exit SubCase1data = "000"& CStr(Hex(Text8.Text)) Case2data = "00"& CStr(Hex(Text8.Text)) Case3data = "0"& CStr(Hex(Text8.Text))Case4data = CStr(Hex(Text8.Text))End SelectIf Err Then'显示出错信息MsgBox Error$, 48, "错误信息"Exit SubEnd IfIf Option11.value ThenCmd = "08"Text1text = CStr(SID) & CStr(Cmd) & CStr(InfoAdd)ElseCmd = "07"Text1text = CStr(SID) & CStr(Cmd) & CStr(InfoAdd) & CStr(data)End IfEnd SubPrivate Function CRC16(data() As Byte) As StringDim CRC16Lo As Byte, CRC16Hi As Byte'CRC寄存器Dim CL As Byte, CH As Byte'多项式码&HA001Dim CRCLo As String, CRCHi As StringDim SaveHi As Byte, SaveLo As ByteDim i As IntegerDim Flag As IntegerCRC16Lo = &HFFCRC16Hi = &HFFCL = &H1CH = &HA0For i = 0To UBound(data)CRC16Lo = CRC16Lo Xor data(i) '每一个数据与CRC寄存器进行异或For Flag = 0To7SaveHi = CRC16HiSaveLo = CRC16LoCRC16Hi = CRC16Hi \ 2'高位右移一位CRC16Lo = CRC16Lo \ 2'低位右移一位If((SaveHi And&H1) = &H1) Then'如果高位字节最后一位为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'如果LSB为1，则与多项式码进行异或CRC16Hi = CRC16Hi Xor CHCRC16Lo = CRC16Lo Xor CLEnd IfNext FlagNext iIf Len(Hex(CRC16Hi)) = 1ThenCRCHi = "0"+ Hex(CRC16Hi)ElseCRCHi = Hex(CRC16Hi)End IfIf Len(Hex(CRC16Lo)) = 1ThenCRCLo = "0"+ Hex(CRC16Lo)ElseCRCLo = Hex(CRC16Lo)End IfCRC16 = CRCLo + CRCHiEnd Function。

基于MODBUS协议的串行通讯例程(VB)

基于MODBUS协议的串行通讯例程（VB）'可通过MODBUS协议获取：主电压、电流、运行状态、DIP开关设置、硬接线状态、统计数据等；'并可通过MODBUS协议控制：启动、急停、软停、双重参数调节、慢速正/反转、节能等；'本例程为通过通讯获取软启动器当前运行状态'编制：董斌 dbboss@Private Const Read_Coil_Status = &H1Private Const Read_Input_Status = &H2Private Const Read_Holding_Registers = &H3Private Const Read_Input_Registers = &H4Private Const Force_Single_Coil = &H5Private Const Single_Registers = &H6Private Const Diagnostics = &H8Private Const Force_Multiple_Coil = &HFPrivate Const Force_Multiple_Register = &H10Public Function CRC16(data() As Byte) As tCRCDim CRC16Hi As ByteDim CRC16Lo As ByteDim Result As tCRCCRC16Hi = &HFFCRC16Lo = &HFFDim i As IntegerDim iIndex As LongFor i = 0 To UBound(data)iIndex = CRC16Lo Xor data(i)CRC16Lo = CRC16Hi Xor GetCRCLo(iIndex) '低位处理CRC16Hi = GetCRCHi(iIndex) '高位处理Next iWith Result.bytLow = CRC16Lo 'CRC低位.bytHigh = CRC16Hi 'CRC高位End WithCRC16 = ResultEnd Function'CRC低位字节值表Private Function GetCRCLo(Ind As Long) As ByteGetCRCLo = Choose(Ind + 1, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80 , &H41, &H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80 , &H41, &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, &H0, &HC1, &H81 , &H40, &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80 , &H41, &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80 , &H41, &H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80 , &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &HC0, &H80 , &H41, &H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80 , &H41, &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80 , &H41, &H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80 , &H41, &H1, &HC0, _&H80, &H41, &H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, &H1, &H C0, &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &H C0, &H80, &H41, &H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, &H1, &H C0, &H80, &H41, &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &H C0, &H80, &H41, &H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, &H1, &H C0, &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &H C0, &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H0, &H C1, &H81, &H40, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &H C0, &H80, &H41, &H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, &H1, &H C0, &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &H C0, &H80, &H41, &H0, &HC1, &H81, &H40)End Function'CRC高位字节值表Private Function GetCRCHi(Ind As Long) As ByteGetCRCHi = Choose(Ind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nd FunctionPublic Function Get_Logic_Status(objRS485_Comm As MSComm, nSerialLink As Byte, _tTimeOut As Double) As tLogic_Status'取软启动器逻辑状态Dim CRC As tCRC, blnTimeOut As BooleanDim outByte() As Byte, T As Double, inByte() As Long, i As Long, r As IntegerDim inChr As String, wStatus As Long, Result As tLogic_StatusReDim outByte(0 To 5) As ByteoutByte(0) = nSerialLink '从设备号outByte(1) = Read_Input_Registers '功能调用号outByte(2) = &H0 '数据所在开始地址(高字节)outByte(3) = &H0 '数据所在开始地址(低字节)outByte(4) = &H0 '读取数据个数（高字节）outByte(5) = &H1 '读取数据个数（低字节）CRC = CRC16(outByte()) '计算CRCReDim Preserve outByte(0 To 7) As ByteWith CRCoutByte(6) = .bytLowoutByte(7) = .bytHighEnd WithobjRS485_Comm.InBufferCount = 0 '清通讯口输入缓存区objRS485_Comm.Output = outByte '输出DoDoEventsLoop Until objRS485_Comm.OutBufferCount = 0 '输出直至完毕T = TimerDoIf Timer - T > tTimeOut Then '超时？blnTimeOut = TrueEnd IfLoop Until (objRS485_Comm.InBufferCount >= 7) Or blnTimeOut '超时或接收数据长度〉7时结束接收If objRS485_Comm.InBufferCount > 0 Then '处理接收数据objRS485_Comm.InputLen = 1i = 0DoinChr = objRS485_Comm.InputReDim Preserve inByte(0 To i) As LonginByte(i) = AscB(inChr)i = i + 1Loop Until objRS485_Comm.InBufferCount = 0wStatus = CLng(inByte(3) * 256) + inByte(4)With Result.blnInsulation = wStatus And &H40& '绝缘报警.blnMotorRunningSlowSpeedReverse = wStatus And &H80& '慢速反转.blnMotorRunningSlowSpeedForward = wStatus And &H100& '慢速正转.blnMotorRunningEnergySaveON = wStatus And &H200& '节能.blnDualAdjON = wStatus And &H400& '双重参数调节.blnMotorRunning = wStatus And &H800& '电机运行.blnMotorStartProcess = wStatus And &H1000& '电机起动过程中.blnMotorSoftStopProcess = wStatus And &H2000& ’电机软停过程中.blnMotorStopped = wStatus And &H4000& ‘电机停止.blnTripped = wStatus And &H8000& ‘跳闸End WithGet_Logic_Status = ResultEnd IfobjRS485_Comm.InBufferCount = 0End Function‘本程序在Windows9x/2k/xp vb6.0 下调试通过。

VB控件Mscomm控件与PLC进行RS485(Modbus)通讯源码

'<<算法>>
Dim CRC_2() As Byte
Dim v As Integer
ReDim CRC_2(K)
For v = 0 To K
CRC_2(v) = Val("&H" & Text1(v).Text)
Next
'==================================================================================================
'
'Next
'Label35.Caption = Str(Val(Asc(Mid(tmp, 6, 1))) / 10)
'
'
' tmp = Mid$(tmp, 6, 4)
'
'
' Dim strHex As String
' Dim Hex2Dec As Long
' Dim strTmp As String
'a = 0
'tmp = 0
'
'
'
' Do While Len(tmp) < 8
'
' tmp = tmp + MSComm1.Input
' testNO.Caption = testNO.Caption + " " + Str(Hex(Asc(tmp)))
' a = a + 1
' If a >= 3000 Then

用VB编写的Modbus通讯CRC16校验程序

用VB编写的Modbus通讯CRC16校验程序(2007-09-27 21:48:19)转载▼标签：IT/科技Rem 声明CRC16冗余校验函数ACS510_CRCPrivate Declare Function ACS510_CRC Lib "ACS510.dll" (ByVal a As Long, ByVal a As Long) As LongPublic Function ACS510_Cmd(ByVal StationID As Long, ByVal WRcmd As Long, ByVal WRAddress As Long, ByVal Data As Long) As StringDim StatID AsString'定义从机地址缓存区Dim Cmd AsString'定义功能命令缓存区Dim Address AsString'定义读写地址缓存区Dim WRAddressHi AsString'定义读写地址的高半字节缓存区Dim WRAddressLo AsString'定义读写地址的低半字节缓存区Dim hData AsString'定义读写数据缓存区Dim DataHi AsString'定义读写数据高半字节缓存区Dim DataLo AsString'定义读写数据低半字节缓存区Dim CRCBuffer1 AsString'定义从机地址校验缓存区Dim CRCBuffer2 AsString'定义命令校验缓存区Dim CRCBuffer3 AsString'定义读写地址高字节校验缓存区Dim CRCBuffer4 AsString'定义读写地址低字节校验缓存区Dim CRCBuffer5 AsString'定义读写数据高半字节校验缓存区Dim CRC AsString'定义读写数据低半字节校验缓存区（也即是CRC计算的最后结果）Dim CRCHi AsString'定义校验高半字节缓存区Dim CRCLo AsString'定义校验低半字节缓存区Dim CRC_Even AsString'定义校验结果取反缓存区Rem 取从机的地址StatID = Trim(Hex(StationID))If StatID = "" ThenMsgBox "目的地地址不能为空！", vbInformation + vbOKOnly, "系统提示！"Exit FunctionElseIf Len(StatID) = 1 ThenStatID = "0" + StatIDEnd IfIf Len(StatID) >= 2 ThenStatID = Trim(Right(StatID, 2))End IfEnd IfRem 取读写命令Cmd = Trim(Hex(WRcmd))If Cmd = "" ThenMsgBox "读写命令不能为空！", vbInformation + vbOKOnly, "系统提示！"Exit FunctionElseIf Len(Cmd) = 1 ThenCmd = "0" + CmdEnd IfIf Len(Cmd) >= 2 ThenCmd = Trim(Right(Cmd, 2))End IfEnd IfRem 取读写数据的地址Address = Trim(Tran_Format(Trim(Hex(WRAddress))))WRAddressHi = Trim(Mid$(Address, 1, 2))WRAddressLo = Trim(Mid$(Address, 3, 2))Rem 取读写的数据（读时为字节数，写时为要写的数据）hData = Trim(Tran_Format(Trim(Hex(Data))))DataHi = Trim(Mid$(hData, 1, 2))DataLo = Trim(Mid$(hData, 3, 2))Rem 计算从机地址的校验CRCBuffer1 = ACS510_CRC(65535, StationID)Rem 计算读写命令的校验CRCBuffer2 = ACS510_CRC(CRCBuffer1, WRcmd)Rem 计算读写地址高半字节的校验If ReadAddressHi = "00" ThenReadAddressHi = ""CRCBuffer3 = CRCBuffer2ElseCRCBuffer3 = ACS510_CRC(CRCBuffer2, Tran_HD(WRAddressHi)) End IfRem 计算读写地址低半字节的校验CRCBuffer4 = ACS510_CRC(CRCBuffer3, Tran_HD(WRAddressLo))Rem 计算读写数据高半字节的校验If DataHi = "00" ThenCRCBuffer5 = CRCBuffer4DataHi = ""ElseCRCBuffer5 = ACS510_CRC(CRCBuffer4, Tran_HD(DataHi)) End IfRem 计算读写数据低半字节的校验，既最终的校验CRC = Trim(Tran_Format(Hex(ACS510_CRC(CRCBuffer5,Tran_HD(DataLo)))))Rem 取校验的高半字节CRCHi = Trim(Mid$(CRC, 1, 2))Rem 取校验的低半字节CRCLo = Trim(Mid$(CRC, 3, 2))Rem 重新组合校验的结果CRC_Even = CRCLo + CRCHiRem 返回发送字符串ACS510_Cmd = StatID + Cmd + WRAddressHi + WRAddressLo + DataHi + DataLo + CRC_EvenEnd Function。

VB与modbus RTU协议通信,并进行CRC校验

VB与modbus rtu协议通信,并进行CRC校验modbus rtu协议可以算是一种事实上的工业标准协议，为许多仪表、PLC等所支持。

以前有几个用户问如何使用VB编程来与我们的KND-K3系列PLC通讯，于是整了一个demo程序。

这次把这个demo共享，希望能给大家一点帮助。

1）模块文件：modCRC，其中包含了CRC校验的函数。

'data 待校验的数组名称'no 数组中元素个数'btLoCRC 算出的CRC高字节'btHiCRC 算出的CRC低字节Public Function CalCRC16Fast(data() As Byte, no As Integer, btLoCRC As Byte, btHiCRC As Byte) As StringDim CL As Byte, CH As Byte '多项式码&HA001Dim SaveHi As Byte, SaveLo As ByteDim i As IntegerDim Flag As IntegerbtHiCRC = &HFFbtLoCRC = &HFFCL = &H1CH = &HA0For i = 0 To (no - 1)btHiCRC = btHiCRC Xor data(i) '每一个数据与CRC寄存器进行异或For Flag = 0 To 7SaveHi = btLoCRCSaveLo = btHiCRCbtLoCRC = btLoCRC \ 2 '高位右移一位btHiCRC = btHiCRC \ 2 '低位右移一位If ((SaveHi And &H1) = &H1) Then '如果高位字节最后一位为1btHiCRC = btHiCRC 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 '如果LSB为1，则与多项式码进行异或btLoCRC = btLoCRC Xor CHbtHiCRC = btHiCRC Xor CLEnd IfNext FlagNext iDim ReturnData(1) As ByteReturnData(0) = btHiCRC 'CRC高位ReturnData(1) = btLoCRC 'CRC低位CalCRC16Fast = ReturnDataEnd FunctionPublic Function CalCRC16Tbl(data() As Byte, no As Integer, btLoCRC As Byte, btHiCRC As Byte) As StringDim btLoCRC As ByteDim btHiCRC As BytebtLoCRC = &HFFbtHiCRC = &HFFDim i As IntegerDim iIndex As LongFor i = 0 To (no - 1)iIndex = btHiCRC Xor data(i)btHiCRC = btLoCRC Xor GetCRCLo(iIndex) '低位处理btLoCRC = GetCRCHi(iIndex)'高位处理Next iDim ReturnData(1) As ByteReturnData(0) = btHiCRC 'CRC高位ReturnData(1) = btLoCRC 'CRC低位CalCRC16Tbl = ReturnDataEnd Function'CRC低位字节值表Function GetCRCLo(Ind As Long) As ByteGetCRCLo = Choose(Ind + 1, _&H0, &HC1, &H81, &H40, &H1, &HC0 , &H80, &H41, &H1, &HC0, _&H80, &H41, &H0, &HC1, &H81, &H4 0, &H1, &HC0, &H80, &H41, _&H0, &HC1, &H81, &H40, &H0, &HC1 , &H81, &H40, &H1, &HC0, _&H80, &H41, &H1, &HC0, &H80, &H4 1, &H0, &HC1, &H81, &H40, _&H0, &HC1, &H81, &H40, &H1, &HC0 , &H80, &H41, &H0, &HC1, _&H81, &H40, &H1, &HC0, &H80, &H4 1, &H1, &HC0, &H80, &H41, _&H0, &HC1, &H81, &H40, &H1, &HC0 , &H80, &H41, &H0, &HC1, _&H81, &H40, &H0, &HC1, &H81, &H4 0, &H1, &HC0, &H80, &H41, _&H0, &HC1, &H81, &H40, &H1, &HC0 , &H80, &H41, &H1, &HC0, _&H80, &H41, &H0, &HC1, &H81, &H4 0, &H0, &HC1, &H81, &H40, _&H1, &HC0, &H80, &H41, &H1, &HC0 , &H80, &H41, &H0, &HC1, _&H81, &H40, &H1, &HC0, &H80, &H4 1, &H0, &HC1, &H81, &H40, _&H0, &HC1, &H81, &H40, &H1, &HC0 , &H80, &H41, &H1, &HC0, _&H80, &H41, &H0, &HC1, &H81, &H4 0, &H0, &HC1, &H81, &H40, _&H1, &HC0, &H80, &H41, &H0, &HC1 , &H81, &H40, &H1, &HC0, _&H80, &H41, &H1, &HC0, &H80, &H4 1, &H0, &HC1, &H81, &H40, _&H0, &HC1, &H81, &H40, &H1, &HC0 , &H80, &H41, &H1, &HC0, _&H80, &H41, &H0, &HC1, &H81, &H4 0, &H1, &HC0, &H80, &H41, _&H0, &HC1, &H81, &H40, &H0, &HC1 , &H81, &H40, &H1, &HC0, _&H80, &H41, &H0, &HC1, &H81, &H4 0, &H1, &HC0, &H80, &H41, _&H1, &HC0, &H80, &H41, &H0, &HC1 , &H81, &H40, &H1, &HC0, _&H80, &H41, &H0, &HC1, &H81, &H4 0, &H0, &HC1, &H81, &H40, _&H1, &HC0, &H80, &H41, &H1, &HC0 , &H80, &H41, &H0, &HC1, _&H81, &H40, &H0, &HC1, &H81, &H4 0, &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, & H41, &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40)End Function'CRC高位字节值表Function GetCRCHi(Ind As Long) As ByteGetCRCHi = Choose(Ind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nd Function2）窗体：FORM1，上面放置的控件如下：Begin VB.Form frmComCaption = "Form1"ClientHeight = 8235ClientLeft = 3885ClientTop = 2250ClientWidth = 6810LinkTopic = "Form1"ScaleHeight = 8235ScaleWidth = 6810Begin VB.TextBox txtReceive ‘注：放置接收上来的IB0数据Height = 495Left = 1200TabIndex = 2Top = 2280Width = 1335EndBegin mandButton Command1Caption = "读取IB0"Height = 495Left = 2760TabIndex = 1Top = 2280Width = 1695EndBegin mandButton cmdSDOCaption = "置位Q1.1"Height = 495Left = 2160TabIndex = 0Top = 3720Width = 1575EndBegin MSCommLib.MSComm ComK3Left = 480Top = 1080_ExtentX = 1005_ExtentY = 1005_Version = 393216DTREnable = -1 'TrueEndEnd①Form_Load事件，在此主要是实现了打开并初始化串口Private Sub Form_Load()With ComK3.CommPort = 1.Settings = "19200,N,8,1".InputMode = comInputModeBinary '二进制收发.InBufferSize = 512.OutBufferSize = 512If (Not .PortOpen) Then .PortOpen = True End WithEnd Sub②Form_UnLoad事件，在此主要是关闭串口Private Sub Form_Unload(Cancel As Integer)If (ComK3.PortOpen) ThenComK3.PortOpen = FalseEnd IfEnd Sub③“置位Q1.1”按钮单击事件'设置Q1.1为1Private Sub cmdSDO_Click()Dim btSend(8) As BytebtSend(0) = &H1 '目标站号btSend(1) = &H5 '功能码btSend(2) = &H0 'Q1.1地址（0009）高字节btSend(3) = &H9 'Q1.1地址（0009）低字节btSend(4) = &HFF '强制值高字节btSend(5) = &H0 '强制值低字节Dim crcDim btCRCHi As Byte, btCRCLo As Bytecrc = CalCRC16Fast(btSend, 6, btCRCLo, btCRCHi)btSend(6) = btCRCHibtSend(7) = btCRCLoComK3.Output = CVar(btSend)End Sub④“读取IB0”按钮单击事件'查表知I0.0的modbus地址为0000，从I0.0开始读取连续8位Private Sub Command1_Click()'发请求Dim btSend(8) As BytebtSend(0) = &H1 '目标站号btSend(1) = &H2 '功能码btSend(2) = &H0 'I0.0地址（0000）高字节btSend(3) = &H0 'i0.0地址（0000）低字节btSend(4) = &H0 '读取个数高字节btSend(5) = &H8 '读取个数低字节Dim crcDim btCRCHi As Byte, btCRCLo As Bytecrc = CalCRC16Fast(btSend, 6, btCRCLo, btCRCHi)btSend(6) = btCRCHibtSend(7) = btCRCLoComK3.Output = CVar(btSend)'注意下面编写的接收过程很简单，要编写实际应用的监控程序来说需要更完善Dim btReceive As VariantWith ComK3DoDoEventsLoop Until .InBufferCount = 6。

VB使用Modbus协议读取TDS-3000温度仪

VB使用Modbus协议读取TDS-3000温度仪因为环境监控工程需要获取机房温度，公司给了我一个三明无线电八厂的TDS-3000温度仪。

使用VB的MSCOMM控件，调试过程很不顺。

首先是将发送命令的代码放在一个过程里，但一运行就提示MSComm1.Output属性使用无效，但相同的代码放在窗体的Load事件里就正常。

再一个是没有注意到这个设备的停止位是2位，所以串口控件设置成“9600,n,8,1”时一直没有数据返回。

另外，看到RS485转RS232的转换器的接收灯一直在闪，可是串口控件的OnComm事件就是没有触发。

以下是调试通过的部分代码：Private Sub TimerMod_Timer()Dim Send(8) As ByteDim SendStr As V ariantDim Receive() As ByteDim ReceiveStr As V ariantSend(0) = &H1Send(1) = &H3Send(2) = &H0Send(3) = &H0Send(4) = &H0Send(5) = &H1Send(6) = 132 'CRC16 HighSend(7) = 10 'CRC16 LoSendStr = SendMSComm1.Output = SendStrDo'这里需要加入超时判断DoEventsLoop Until MSComm1.InBufferCount >= 7MSComm1.InputLen = 0ReceiveStr = MSComm1.InputReceive = ReceiveStrText1.Text = CStr(HexToDec(Hex$(Receive(3)) & Hex$(Receive(4))))End SubFunction HexToDec(str)Dim nums_len As IntegerDim i As IntegerDim tmpstr As StringDim dummy, tmp As Integerdummy = 0nums_len = Len(str)For i = 1 To nums_lentmpstr = Mid(str, i, 1)If IsNumeric(tmpstr) Thentmp = CInt(tmpstr) * 16 * (16 ^ (nums_len - i - 1))ElseIf Asc(UCase(tmpstr)) < 65 Or Asc(UCase(tmpstr)) > 70 ThenHexToDec = -1Exit FunctionEnd Iftmp = (Asc(UCase(tmpstr)) - 55) * (16 ^ (nums_len - i)) End Ifdummy = dummy + tmpNextHexToDec = dummyEnd Function。

MODBUS vb实现

Private Sub btnSend_Click(Index As Integer)Select Case IndexCase 0 '03命令测试' MsgBox (cmbSlId(0).Text)Label9.Caption = CommandQuery03(cmbSlId(0).Text, Val(cmbRegAdd(0).Text) - 1, cmbDataType(0).Text)lblSlaveStatus(0).Caption = "读从机，等待！"Case 1 '16命令测试If Not IsNumeric(txtWriteData.Text) ThenMsgBox ("请输入数据！")txtSend(1).Text = ""txtSend(1).SetFocusExit SubEnd IftxtSend(1).Text = CommandQuery16(cmbSlId(1).Text, Val(cmbRegAdd(1).Text), cmbDataType(1).Text, txtWriteData.Text)lblSlaveStatus(1).Caption = "写从机,等待响应"txtReceive(1).Text = ""Case 2 '08命令测试If Not IsNumeric(txtDignoseAsk.Text) ThenMsgBox ("请输入数据！")txtSend(2).Text = ""txtDignoseAsk.Text = ""txtDignoseAsk.SetFocusExit SubEnd IftxtSend(2).Text = CommandQuery08(cmbSlId(2).Text, cmbDataType(2).Text, txtDignoseAsk.Text)lblSlaveStatus(2).Caption = "诊断从机,等待响应"txtReceive(2).Text = ""txtDignoseBack.Text = ""Case ElseEnd SelectEnd SubPrivate Sub Command1_Click()On Error Resume NextSetPortWith MSComm1If .PortOpen = True Then.PortOpen = FalseCommand1.Caption = "打开串口"Shape1.FillColor = &HFF&Label11.Caption = "串口已关闭"Label6.Caption = "串口状态：关闭"ElseCommand1.Caption = "关闭串口".PortOpen = TrueLabel6.Caption = "串口状态：打开"Shape1.FillColor = &HC000&Label11.Caption = "串口已打开"If Err.Number <> 0 ThenLabel11.Caption = "串口已使用"Err.ClearEnd IfEnd IfEnd With'MsgBox (MSComm1.PortOpen)End SubPrivate Sub SetPort()Dim curPortOpen As BooleanDim intCommPort As IntegerDim strCheckBit As StringDim strSettings As StringDim i As IntegerSelect Case Combo1.TextCase "COM1"intCommPort = 1Case "COM2"intCommPort = 2Case "COM3"intCommPort = 3Case "COM4"intCommPort = 4Case "COM5"intCommPort = 5Case "COM6"intCommPort = 6Case "COM7"intCommPort = 7Case "COM8"intCommPort = 8Case "COM9"intCommPort = 9Case ElseintCommPort = 1End SelectSelect Case Combo2.TextCase "NONE"strCheckBit = "n"Case "EVEN"strCheckBit = "e"Case "ODD"strCheckBit = "o"Case ElsestrCheckBit = "n"End Select'9600,n,8,1strSettings = Combo4.Text & "," & strCheckBit & "," & Combo5.Text & "," & Combo3.Text curPortOpen = MSComm1.PortOpenmPort = intCommPortMSComm1.Settings = strSettingsIf (Command1.Caption = "打开连接") ThenShape1.FillColor = &HFF&MSComm1.PortOpen = TrueCommand1.Caption = "关闭连接"ElseIf (MSComm1.PortOpen = True) ThenMSComm1.PortOpen = FalseEnd IfEnd IfEnd SubPrivate Sub MSComm1_Click()End SubPrivate Sub Form_Load()Combo5.AddItem (8)Combo5.AddItem (7)Combo3.AddItem (1)Combo3.AddItem (2)Dim i As IntegercmbDataType(0).AddItem ("16位整数")cmbDataType(0).AddItem ("32位整数")cmbDataType(0).AddItem ("64位整数")cmbDataType(0).AddItem ("32位浮点型")For i = 1 To 255cmbSlId(0).AddItem (i)Next icmbSlId(0).Text = 1cmbDataType(0).Text = "16位整数"For m = 1 To 1000cmbRegAdd(0).AddItem (m)Next mcmbRegAdd(0).Text = 100End SubPublic Function CommandQuery03(strSlaveAdd As String, strBeginAdd As String, strDataType As String) As StringDim longCRC As LongDim i As IntegerDim strQuery As StringbyteModbusQurey(0) = strSlaveAdd 'Slave AddbyteModbusQurey(1) = 3 'FunctionbyteModbusQurey(2) = 0 'RegAddHibyteModbusQurey(3) = strBeginAdd 'RegAddLobyteModbusQurey(4) = 0 'RegNumHiSelect Case strDataType 'RegNumLoCase "16位整数"byteModbusQurey(5) = 1Case "32位整数"byteModbusQurey(5) = 2Case "64位整数"byteModbusQurey(5) = 4Case "32位浮点数"byteModbusQurey(5) = 2Case ElsebyteModbusQurey(5) = 1'cmbDataType(0).Text = "16位整数"End SelectlongCRC = CRC16(byteModbusQurey, 6)byteModbusQurey(6) = (longCRC And &HFF00) \ 256 'CRCHibyteModbusQurey(7) = longCRC And &HFF 'CRCLostrQuery = ""For i = 0 To 7strQuery = strQuery + ByteDataToString(byteModbusQurey(i)) + " "Next iCommandQuery03 = strQueryintQueryNum = 8Call SendCommand(byteModbusQurey, intQueryNum)'lblSlaveStatus(0).Caption = "读取从机,等待响应"End Function'****************************************************************************** ********************************'Private Function CommandQuery16(strSlaveAdd As String, strBeginAdd As String, strDataType As String,cryWriteData as currency) As String'功能: 16号命令'参数: 无'返回: 无'修改历史:'****************************************************************************** ********************************Public Function CommandQuery16(strSlaveAdd As String, strBeginAdd As String, strDataType As String, strWriteData As String) As StringDim longCRC As LongDim i As IntegerDim strQuery As StringDim byteByteData() As ByteDim cryData As CurrencyDim intByteDataLength As IntegerDim byteTmp(1) As BytebyteModbusQurey(0) = strSlaveAdd 'Slave AddbyteModbusQurey(1) = 16 'FunctionbyteModbusQurey(2) = 0 'RegAddHibyteModbusQurey(3) = strBeginAdd 'RegAddLobyteModbusQurey(4) = 0 'RegNumHiSelect Case strDataType 'RegNumLoCase "16位整数"byteModbusQurey(5) = 1Case "32位整数"byteModbusQurey(5) = 2Case "64位整数"byteModbusQurey(5) = 4Case "32位浮点数"byteModbusQurey(5) = 2Case ElsebyteModbusQurey(5) = 1cmbDataType(1).Text = "16位整数"End SelectbyteModbusQurey(6) = byteModbusQurey(5) * 2 'ByteNumcryData = strWriteDatabyteByteData = DataToByteArray(cryData, strDataType)'按字倒序intByteDataLength = UBound(byteByteData) + 1For i = 0 To intByteDataLength \ 2 - 1 Step 2byteTmp(0) = byteByteData(i)byteTmp(1) = byteByteData(i + 1)byteByteData(i) = byteByteData(intByteDataLength - 2 - i)byteByteData(i + 1) = byteByteData(intByteDataLength - 2 + 1 - i)byteByteData(intByteDataLength - 2 - i) = byteTmp(0)byteByteData(intByteDataLength - 2 + 1 - i) = byteTmp(1)Next i'写入的数据加入请求数组For i = 0 To intByteDataLength - 1byteModbusQurey(7 + i) = byteByteData(i)Next ilongCRC = CRC16(byteModbusQurey, 7 + byteModbusQurey(6))byteModbusQurey(7 + byteModbusQurey(6)) = (longCRC And &HFF00) \ 256 'CRCHibyteModbusQurey(8 + byteModbusQurey(6)) = longCRC And &HFF'CRCLostrQuery = ""For i = 0 To 8 + byteModbusQurey(6)strQuery = strQuery + ByteDataToString(byteModbusQurey(i)) + " "Next iCommandQuery16 = strQueryintQueryNum = 9 + byteModbusQurey(6)Call SendCommand(byteModbusQurey, intQueryNum)End Function'****************************************************************************** ********************************'Private Function CommandQuery08(strSlaveAdd As String, strDataType As String, cryDignoseData As Currency) As String'功能: 08号命令'参数: 无'返回: 无'修改历史:'****************************************************************************** ********************************Public Function CommandQuery08(strSlaveAdd As String, strDataType As String, cryDignoseData As Currency) As StringDim longCRC As LongDim i As IntegerDim strQuery As StringDim byteByteData() As ByteDim cryData As CurrencyDim intByteDataLength As IntegerDim byteTmp(1) As BytebyteModbusQurey(0) = strSlaveAdd 'Slave AddbyteModbusQurey(1) = 8 'FunctionbyteModbusQurey(2) = 0 'Subfunction HibyteModbusQurey(3) = 0 'Subfunction LocryData = cryDignoseDatabyteByteData = DataToByteArray(cryData, strDataType)byteModbusQurey(4) = byteByteData(0)byteModbusQurey(5) = byteByteData(1)longCRC = CRC16(byteModbusQurey, 6)byteModbusQurey(6) = (longCRC And &HFF00) \ 256 'CRCHibyteModbusQurey(7) = longCRC And &HFF 'CRCLostrQuery = ""For i = 0 To 7strQuery = strQuery + ByteDataToString(byteModbusQurey(i)) + " "Next iCommandQuery08 = strQueryintQueryNum = 8Call SendCommand(byteModbusQurey, intQueryNum)End FunctionPublic Function CRC16(data() As Byte, length As Integer) As Long Dim i As Integer, j As IntegerDim Bit As BooleanDim Temp As ByteDim CRC As LongDim Generator As LongCRC = 65535Generator = 40961For i = 0 To length - 1Temp = data(i)CRC = CRC Xor TempFor j = 1 To 8Bit = CRC And 1CRC = CRC \ 2If Bit = True ThenCRC = CRC Xor GeneratorEnd IfNext jNext iCRC16 = CRC \ 256CRC = (CRC - CRC16 * 256) * 256CRC16 = CRC + CRC16End FunctionPublic Function ByteDataToString(data As Byte) As StringDim OutString As StringDim datahi As ByteDim datalo As Bytedatahi = data \ 16datalo = data And &HFSelect Case datahiCase 0OutString = "0"Case 1OutString = "1"Case 2OutString = "2"Case 3OutString = "3"Case 4OutString = "4"Case 5OutString = "5"Case 6OutString = "6"Case 7OutString = "7"Case 8OutString = "8"Case 9OutString = "9"Case 10OutString = "A"Case 11OutString = "B"Case 12OutString = "C"Case 13OutString = "D"Case 14OutString = "E"Case 15OutString = "F"Case ElseOutString = "0"End SelectSelect Case dataloCase 0OutString = OutString + "0" Case 1OutString = OutString + "1" Case 2OutString = OutString + "2" Case 3OutString = OutString + "3" Case 4OutString = OutString + "4" Case 5OutString = OutString + "5" Case 6OutString = OutString + "6"Case 7OutString = OutString + "7"Case 8OutString = OutString + "8"Case 9OutString = OutString + "9"Case 10OutString = OutString + "A"Case 11OutString = OutString + "B"Case 12OutString = OutString + "C"Case 13OutString = OutString + "D"Case 14OutString = OutString + "E"Case 15OutString = OutString + "F"Case ElseOutString = OutString + "0"End SelectByteDataToString = OutStringEnd FunctionPublic Sub SendCommand(byteQueryArr() As Byte, length As Integer) Dim byteQ() As ByteDim i As IntegerReDim byteQ(length) As ByteFor i = 0 To length - 1byteQ(i) = byteQueryArr(i)Next iIf MSComm1.PortOpen = True ThenMSComm1.OutBufferCount = 0 '清空发送缓冲区MSComm1.Output = byteQintResponseNum = 0MSComm1.InBufferCount = 0 '清空接收缓冲区MSComm1.RThreshold = 1'等待接收数据timerReceiveTimeOut.Interval = 3000 '三秒无数据报错误timerReceiveTimeOut.Enabled = True '启动定时器End IfEnd SubPublic Sub delay(ms As Integer)Dim Savetime As DoubleSavetime = timeGetTime '记下开始时的时间While timeGetTime < Savetime + ms '循环等待DoEvents '转让控制权，以便让操作系统处理其它的事件。

用VB实现Modbus串行通讯

如何用VB实现Modbus串行通讯在一些应用中可能需要使用诸如VB来进行上位机监控程序的开发，而Modbus协议是这类应用中首选的通讯协议；Modbus协议以其简单易用，在工业领域里已广泛的为其他第三方设备所支持。

这里对VB和Twido PLC间的通讯进行说明。

对于大部分应用，Twido PLC作为从站，它不需要编制通讯程序，只要把通讯口的参数设置好即可，例如下图表示此Twido通过编程口和上位机连接，其站号地址为2；波特率、数据位、校验、停止位和上位机设置保持一致。

VB程序通过利用MSComm控件很容易就能够实现。

1．通讯口初始化：MSComm1.Settings = "9600,n,8,1"mPort = 1MSComm1.SThreshold = 0If Not MSComm1.PortOpen Then MSComm1.PortOpen = True2．CRC校验码的计算方法，如以下函数，可以得到字节数组变量cmdstring指向的字符串的CRC校验码。

Function crc16_1(ByRef cmdstring() As Byte, ByVal j As Integer)Dim data As IntegerDim i As IntegerAddressreg_crc = &HFFFFFor i = 0 To jAddressreg_crc = Addressreg_crc Xor cmdstring(i)For j = 0 To 7data = Addressreg_crc And &H1If data ThenAddressreg_crc = Int(Addressreg_crc / 2)Addressreg_crc = Addressreg_crc And &H7FFFAddressreg_crc = Addressreg_crc Xor &HA001ElseAddressreg_crc = Addressreg_crc / 2Addressreg_crc = Addressreg_crc And &H7FFFEnd IfNext jNext iIf Addressreg_crc < 0 ThenAddressreg_crc = Addressreg_crc - &HFFFF0000End IfHiByte = Addressreg_crc And &HFFLoByte = (Addressreg_crc And &HFF00) / &H100End Function3．读多个字的命令（本例是从2号站读%MW10起始的4个字）：Dim SendStr(7) As ByteDim RcvStr() As ByteSendStr(0) = 2 ,从站号是2SendStr(1) = &H3 ,读多个字的命令代码SendStr(2) = 0 ,起始地址高字节SendStr(3) = 10,起始地址低字节SendStr(4) = &H0,数据长度高字节SendStr(5) = 4 ,数据长度低字节Call crc16(SendStr(), 5) ,CRC计算SendStr(6) = HiByteSendStr(7) = LoByte,读命令发送后,当接收5 + SendStr(5) * 2 个字节时产生中断CmdLenth = 5 + SendStr(5) * 2MSComm1.RThreshold = CmdLenthMSComm1.Output = SendStr ,发送命令4．写多个字的命令（本例是写2号站%MW20起始的3个字）：Dim WriteStr() As Bytek = 6 ,写6个字节ReDim WriteStr(8 + k)WriteStr(0) = 2 ,从站号是2WriteStr(1) = &H10 ,写多个字的命令代码WriteStr(2) = 0 ,起始地址高字节WriteStr(3) = 20 ,起始地址低字节WriteStr(4) = &H0 ,数据长度高字节<字的个数> WriteStr(5) = k / 2 ,数据长度低字节<字的个数>WriteStr(6) = k ,数据长度<字节的个数> WriteStr(7) = &H12,写的第1个字的高字节WriteStr(8) = &H34,写的第1个字的低字节WriteStr(9) = &H56,写的第2个字的高字节WriteStr(10) = &H78,写的第2个字的低字节WriteStr(11) = &H9A,写的第3个字的高字节WriteStr(12) = &HBC,写的第3个字的低字节Call crc16(WriteStr(), 6 + k)WriteStr(9 + (k / 2 - 1) * 2) = HiByteWriteStr(10 + (k / 2 - 1) * 2) = LoByteMSComm1.InBufferCount = 0MSComm1.Output = WriteStr,写命令发送后,当接收到8个字节时中断CmdLenth = 8MSComm1.RThreshold = CmdLenth5．通讯事件中断产生时的数据处理：Private Sub MSComm1_OnComm()Dim inx() As ByteSelect Case mEventCase comEvReceive ,判断为接收事件MSComm1.InputLen = CmdLenth ,接收数据的长度inx = MSComm1.Input ,接收数据MSComm1.InBufferCount = 0For k = 3 To CmdLenth - 3tmpstr = tmpstr & "/" & Hex(inx(k))NextText1.Text = tmpstr ,以十六进制显示所接收长度的数据BeepEnd SelectEnd Sub。

用VB写的modbusrtu模式通讯源码

用VB写的modbusrtu模式通讯源码‘用VB 写的modbus rtu模式通讯源码，已在台达PLC上调试通过Private Sub CmdOpen_Click()On Error Resume NextIf (MSComm1.PortOpen) Then ‘打开/关闭串口MSComm1.PortOpen = FalseElseMSComm1.PortOpen = TrueEnd IfIf (MSComm1.PortOpen) ThenCmdOpen.Caption = "关闭串口"Shape5.FillStyle = vbFSSolidElseCmdOpen.Caption = "打开串口"Shape5.FillStyle = vbFSTransparentEnd IfIf Err ThenMsgBox Error$, 48, "错误码信息"Exit SubEnd IfEnd SubPrivate Sub Combo1_Click()/doc/df18763589.html,mPort = Combo1.ListIndex + 1End SubPrivate Sub Combo2_Click()Call SettingEnd SubPrivate Sub Combo3_Click()Call SettingEnd SubPrivate Sub Combo4_Click()Call SettingEnd SubPrivate Sub Combo5_Click()Call SettingEnd SubPrivate Sub Command1_Click()‘S hape1.FillStyle = vbFSSolidDim Y0_status As ByteDim Sendstr As StringDim i As Integer, j As IntegerSendstr = "01 01 05 00 00 10 "HexSend (Sendstr)Sleep (30)HexSend (Sendstr)End SubPrivate Function HexSend(Sendstr As String) As Integer Dim outbuf() As ByteDim Temp(0) As ByteDim crc As String, Sendstrls As StringDim sendlen As IntegerDim i As Integer, j As IntegerIf Sendstr = "" ThenMsgBox "发送数据不能为空！"HexSend = 0Exit FunctionEnd IfS endstrls = Trim(Sendstr) ‘去掉空格sendlen = Len(Sendstrls) + 1 ‘取长度j = 0ReDim outbuf(1 To sendlen \ 3) As ByteFor i = 1 To sendlen Step 3j = j + 1outbuf(j) = Val("&H" & CStr(Mid(Sendstrls, i, 2)))Next icrc = Crc16(outbuf)ReDim Preserve outbuf(1 T o (sendlen \ 3 + 2)) As Byte ‘加上CRC校验码outbuf(sendlen \ 3 + 1) = Val("&H" & CStr(Mid(crc, 1, 2)))outbuf(sendlen \ 3 + 2) = Val("&H" & CStr(Mid(crc, 3, 2)))For i = 1 To (sendlen \ 3 + 2)Temp(0) = outbuf(i)MSComm1.Output = TempNext iFor i = 1 To 2000Next iHexSend = 1End FunctionPrivate Function Setting()MSComm1.Settings = CStr(Combo2.Text) & "," & CStr(Combo3.Text) & "," & CStr(Combo4.Text) & "," & CStr(Combo5.Text) End FunctionPrivate Sub Command2_Click()‘If (MSComm1.RThreshold = 0) Then‘MSComm1.RTh reshold = 1‘Else‘MSComm1.RThreshold = 0‘End IfLabel11.Caption = "接收个数:" & CStr(ReceCount) & " " & "接收帧数：" & CStr(Framecount) End SubPrivate Sub Form_Load()Combo1.AddItem ("COM1")Combo1.AddItem ("COM2")Combo1.AddItem ("COM3")Combo1.AddItem ("COM4")Combo1.AddItem ("COM5")Combo1.ListIndex = 0Combo2.AddItem ("2400")Combo2.AddItem ("4800")Combo2.AddItem ("9600")Combo2.AddItem ("11520")Combo2.ListIndex = 0Combo3.AddItem ("E")Combo3.AddItem ("O")Combo3.AddItem ("N")Combo3.ListIndex = 2Combo4.AddItem ("6")Combo4.AddItem ("7")Combo4.AddItem ("8")Combo4.ListIndex = 2Combo5.AddItem ("1")Combo5.AddItem ("2")Combo5.ListIndex = 0ReceCount = 0End SubPrivate Function Crc16(data() As Byte) As StringDim CRC16Lo As Byte, CRC16Hi As Byte ‘CRC寄存器Dim CL As Byte, CH As Byte ‘多项式码&HA001Dim CrcLo As String, CrcHi As StringDim SaveHi As Byte, SaveLo As ByteDim i As IntegerDim Flag As IntegerCRC16Lo = &HFFCRC16Hi = &HFFCL = &H1CH = &HA0For i = 1 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CRC16Lo = CRC16Lo \ 2 ‘低位右移一位If ((SaveHi And &H1) = &H1) Then ‘如果高位字节最后一位为1CRC16Lo = CRC16Lo Or &H80 ‘则低位字节右移后前面补1 End If ‘否则自动补0If ((SaveLo And &H1) = &H1) Then ‘如果LSB为1，则与多项式码进行异或CRC16Hi = CRC16Hi Xor CHCRC16Lo = CRC16Lo Xor CLEnd IfNext FlagNext iIf Len(Hex(CRC16Hi)) = 1 ThenCrcHi = "0" + Hex(CRC16Hi)ElseCrcHi = Hex(CRC16Hi)End IfIf Len(Hex(CRC16Lo)) = 1 ThenCrcLo = "0" + Hex(CRC16Lo)ElseCrcLo = Hex(CRC16Lo)End IfCrc16 = CrcLo & CrcHiEnd FunctionPrivate Sub MSComm1_OnComm()Dim inpu() As ByteDim i As IntegerDim tempstr As String, Strdata As StringSelect Case /doc/df18763589.html,mEvent Case comEvReceive ‘接收事件tempstr = MSComm1.Inputinpu() = tempstrFramecount = Framecount + 1 ‘帧个数加1If (Framecount = 1) Thenframepoint(Framecount) = UBound(inpu) + 1 ‘第一帧帧尾Elseframepoint(Framecount) = framepoint(Framecount - 1) + UBound(inpu) + 1 ‘第二帧开始指针End IfFor i = 0 To UB ound(inpu) ‘将字符转换为数组If (Len(Hex(inpu(i))) = 1) ThenStrdata = Strdata & "0" & Hex(inpu(i)) & " "ElseStrdata = Strdata & Hex(inpu(i)) & " "End IfNext iFor i = ReceCount + 1 To UBound(inpu) + 1 ‘数据进入缓冲区Recebuf(i) = inpu(i - 1)NextReceCount = ReceCount + UBound(inpu) + 1TextReceive.Text = TextReceive.Text & StrdataStrdata = ""Case comEvSendEnd SelectEnd SubPrivate Function RtuCheck(data() As Byte) As IntegerDim CrcHi As Byte, CrcLo As ByteDim Checkdata() As ByteDim i As IntegerDim crc As StringCrcHi = data(UBound(data))CrcLo = data(UBound(data) - 1)ReDim Checkdata(1 To (UBound(data) - 1)) As ByteFor i = 1 To (UBound(data) - 1) ‘附值Checkdata(i) = data(i - 1)Nextcrc = Crc16(Checkdata)If (CrcLo = Val("&H" & CStr(Mid(crc, 1, 2))) And CrcHi = Val("&H" & CStr(Mid(crc, 3, 2)))) Then RtuCheck = 1ElseRtuCheck = 0End IfEnd Function。

MODBUS VB代码

'Global Data DefinitionsDim MyHandle As Long 'Handle to ConnectionDim MyStatus As Integer 'Status returned from mbMasterV7 Control Dim Slave As Integer 'Slave, Cmd, Address, & LengthDim Cmd As IntegerDim Address As LongDim Length As IntegerDim LoopbackMsg(20) As BytePublic Sub show_status(ErrCode As Integer)If (ErrCode = 0) ThenSTATUS.Text = "正常通行ing"ElseIf (ErrCode < 255) Then' STATUS.Text = "Slave Device Exception Response"STATUS.Text = "从设备没有响应"ElseIf (ErrCode = 256) ThenSTATUS.Text = "无效连接"ElseIf (ErrCode = 257) ThenSTATUS.Text = "消息超时"ElseIf (ErrCode = 258) ThenSTATUS.Text = "无效地址"ElseIf (ErrCode = 259) ThenSTATUS.Text = "无效从设备地址"ElseIf (ErrCode = 260) ThenSTATUS.Text = "无效数据长度"ElseIf (ErrCode = 261) ThenSTATUS.Text = "不支持modbus命令格式"ElseIf (ErrCode = 263) ThenSTATUS.Text = "从设备超时"ElseIf (ErrCode = 264) ThenSTATUS.Text = "无效传输模式"ElseIf (ErrCode = 265) ThenSTATUS.Text = "CRC校验错误"ElseIf (ErrCode = 266) ThenSTATUS.Text = "没有建立连接"ElseIf (ErrCode = 267) ThenSTATUS.Text = "无效从设备响应"ElseIf (ErrCode = 271) ThenSTATUS.Text = "演示时间到"ElseIf (ErrCode = 272) ThenSTATUS.Text = "无效modbus/TCP 命令"End IfEnd Sub' Hide the contrtol when the form loadsPrivate Sub Form_Activate()MbMasterV71.HideControlEnd Sub' Handler for the CONNECT SERIAL ButtonPrivate Sub ConnectSerial_Click()' Connect to COMM PortMbMasterV71.BaudRate = 9600 '9600 BaudMbMasterV71.Parity = 0 '0=NOPARITY, 1=ODDPARITY, 2=EVENPARITY, 3=MARKPARITY, 4=SPACEPARITYMbMasterV71.DataBits = 8 '8 DataBitsMbMasterV71.StopBits = 0 '0=ONESTOPBIT, 1=ONE5STOPBITS, 2=TWOSTOPBITSMbMasterV71.TimeOut = 2000 '2000 msecMbMasterV71.TransmissionMode = 1 '0=ASCII, 1=RTUMyHandle = MbMasterV71.ConnectSerial(1) ' Connect to COMM Port 1If MyHandle > 0 Then' Connection was successful' (This example only allows a single connection)' Disable All Connection Buttons' Enable the Read, Write & Disconnect ButtonsConnectSerial.Enabled = FalseConnectTAPI.Enabled = FalseConnectTCP.Enabled = FalseDisconnect.Enabled = True' LoopBackTst.Enabled = TrueSTATUS.Text = "正在连接ing"READMODBUS.Enabled = TrueWRITEMODBUS.Enabled = TrueElse'Connection Attempt Failed'(Another application must have control of the COM Port)STATUS.Text = "串口忙，请稍候"End IfEnd Sub' Handler for the CONNECT TAPI ButtonPrivate Sub ConnectTAPI_Click()Dim nTAPIDevices As LongDim TAPIDevice As String'Go through the motions of getting the TAPI Device ListnTAPIDevices = MbMasterV71.NumberOfTAPIDevices()TAPIDevice = MbMasterV71.GetTAPIDeviceName(0)'Setup the phone number to dialMbMasterV71.PhoneNumber = "645-5966"'Dial the callMyHandle = MbMasterV71.DialTAPIDevice(0)If MyHandle > 0 Then'Call should be in progress now'Don't enable the Read & Write Buttons'until we get the CallEstablished EventSTATUS.Text = "正在连接ing"ConnectSerial.Enabled = FalseConnectTAPI.Enabled = FalseConnectTCP.Enabled = FalseDisconnect.Enabled = False'LoopBackTst.Enabled = FalseREADMODBUS.Enabled = FalseWRITEMODBUS.Enabled = FalseElseSTATUS.Text = "没有连接"End IfEnd Sub' Handler for the CONNECT TCP ButtonPrivate Sub ConnectTCP_Click()' Select the Device to connec to' In this case use the IP Loopback address to' connect to the local machineMbMasterV71.TCPDevice = "127.0.0.1"MyHandle = MbMasterV71.ConnectModbusTCP(502)If MyHandle > 0 Then'Connection should be in progress now'Don't enable the Read & Write Buttons'until we get the CallEstablished EventSTATUS.Text = "正在连接ing"ConnectSerial.Enabled = FalseConnectTAPI.Enabled = FalseConnectTCP.Enabled = FalseDisconnect.Enabled = False' LoopBackTst.Enabled = FalseREADMODBUS.Enabled = FalseWRITEMODBUS.Enabled = FalseElseSTATUS.Text = "没有连接"End IfEnd Sub' ConnectionEstablished Event Handler' Initiated from either ConnectModbusTCP() or DialTAPIDevice()Private Sub MbMasterV71_ConnectionEstablished(ByVal hConnect As Long)'Enable the Disconnect Button'Enable Read & Write ButtonsConnectSerial.Enabled = FalseConnectTAPI.Enabled = FalseConnectTCP.Enabled = FalseDisconnect.Enabled = True'LoopBackTst.Enabled = TrueSTATUS.Text = "正常通信ing"READMODBUS.Enabled = TrueWRITEMODBUS.Enabled = TrueEnd Sub' ConnectionDropped Event HandlerPrivate Sub MbMasterV71_ConnectionDropped(ByVal hConnect As Long) 'Either the TCP or TAPI connection attempt failed'or something has happened to abort the connection after it'has been established for a while.'In either case we're now disconnected so enable the'buttons accordinglyMyHandle = -1ConnectSerial.Enabled = TrueConnectTAPI.Enabled = TrueConnectTCP.Enabled = TrueDisconnect.Enabled = False'LoopBackTst.Enabled = FalseSTATUS.Text = "没有连接"READMODBUS.Enabled = FalseWRITEMODBUS.Enabled = FalseEnd Sub' Handler for the DISCONNECT ButtonPrivate Sub Disconnect_Click()'Tell the control to DisconnectMyStatus = MbMasterV71.Disconnect(MyHandle)MyHandle = -1'ReEnable the Connect Buttons for new connection attemptConnectSerial.Enabled = TrueConnectTAPI.Enabled = TrueConnectTCP.Enabled = TrueDisconnect.Enabled = False'LoopBackTst.Enabled = FalseSTATUS.Text = "没有连接"READMODBUS.Enabled = FalseWRITEMODBUS.Enabled = FalseEnd SubPrivate Sub Frame2_DragDrop(Source As Control, X As Single, Y As Single)End Sub' Handler for the READ ButtonPrivate Sub READMODBUS_Click()'Get the Slave Node Address, Modbus Command, Address & Length' from the appropriate Edit controlsSlave = NODEADDRESS.TextCmd = POINTTYPE.TextAddress = READADDRESS.TextLength = READLENGTH.Text'We must remember these parameters so we can use'them in the ReadResponse method to make sure we'get what we ask for''Initiate the Read RequestMyStatus = MbMasterV71.PollModbus(MyHandle, Slave, Cmd, Address, Length)'Check the status to make sure the request went out.If MyStatus = 0 ThenSTATUS.Text = "串口忙,请稍侯"Elseshow_status (MyStatus)End IfEnd Sub'Process the Slave Read Response Message'Modbus_Master SlaveReadResponse Event HandlerPrivate Sub MbMasterV71_SlaveReadResponse(ByVal hConnect As Long)Dim MyData As LongDim i As Integer' Read the data returned from the slave' and update the text controlsFor i = 0 To Length - 1MyStatus = MbMasterV71.ReadResults(hConnect, Slave, Cmd, Address + i, MyData) show_status (MyStatus)If MyStatus = 0 Then'Text1(i).Text = MyDataIf i = 0 Or i = 8 Or i = 16 ThenText1(i).Text = MyData * 系数End IfIf i = 2 Or i = 10 Or i = 18 ThenText1(i).Text = MyData * 系数End IfIf i = 4 Or i = 12 Or i = 20 Or i = 6 Or i = 14 Or i = 22 ThenText1(i).Text = MyData * 系数End IfIf i = 28 Or i = 30 Then '3P,3QText1(i).Text = MyData * 系数End IfIf i = 29 Then 'cosqText1(i).Text = MyData * 系数End IfIf i = 27 Then 'FText1(i).Text = MyData * 系数End IfIf i = 1 Or i = 5 Or i = 7 Or i = 9 Or i = 13 Or i = 15 Or i = 17 Or i = 21 Or i = 23 Or i = 25 Or i = 23 Or i = 26 Or i = 31 ThenText1(i).Text = 0 '没有测量的量默认为0End If' Else' Text1(i).Text = "Error"End IfNext iEnd SubPrivate Sub WRITEMODBUS_Click()Dim IsRegister As BooleanDim i As IntegerDim junk As IntegerSlave = NODEADDRESS.TextAddress = WRITEADDRESS.TextLength = WRITELENGTH.T extIf Length > 200 ThenLength = 200End IfFor i = 0 To Length - 1junk = MbMasterV71.FillWriteBuffer(MyHandle, i, PATTERN.Text)Next iIf POINTTYPE.Text < 2 ThenIf Length = 1 ThenCmd = 5 'write single coilElseCmd = 15 'write multiple coilsEnd IfElseIf Length = 1 ThenCmd = 6 'write single registerElseCmd = 16 'write multiple registersEnd IfEnd IfMyStatus = MbMasterV71.WRITEMODBUS(MyHandle, Slave, Cmd, Address, Length) ' Make sure the write request was transmittedIf MyStatus = 0 ThenSTATUS.Text = "串口忙,请稍侯"Elseshow_status (MyStatus)End IfEnd Sub'Process the Slave Write Response Message'Modbus_Master SlaveWriteResponse Event HandlerPrivate Sub MbMasterV71_SlaveWriteResponse(ByVal hConnect As Long) 'read the results of the write requestMyStatus = MbMasterV71.WriteResults(hConnect, Slave, Cmd, Address, Length) ' and update the status displayshow_status (MyStatus)End SubPrivate Sub LoopBackTst_Click()Slave = NODEADDRESS.TextCmd = 8MyStatus = MbMasterV71.FillUserMsgBuffer(MyHandle, 0, Slave)MyStatus = MbMasterV71.FillUserMsgBuffer(MyHandle, 1, Cmd)MyStatus = MbMasterV71.FillUserMsgBuffer(MyHandle, 2, 0)MyStatus = MbMasterV71.FillUserMsgBuffer(MyHandle, 3, 0)MyStatus = MbMasterV71.FillUserMsgBuffer(MyHandle, 4, 0)MyStatus = MbMasterV71.FillUserMsgBuffer(MyHandle, 5, 0)MyStatus = MbMasterV71.SendUserMsg(MyHandle, 6)'Check the status to make sure the request went out.If MyStatus = 0 ThenSTATUS.Text = "串口忙,请稍侯"Elseshow_status (MyStatus)End IfEnd SubPrivate Sub MbMasterV71_UserMsgResponse(ByVal hConnect As Long, ByVal NumberOfBytes As Long)Dim temp As IntegerIf NumberOfBytes > 0 ThenFor i = 0 To NumberOfBytes - 1MyStatus = MbMasterV71.ReadUserMsgResponse(hConnect, i, temp)LoopbackMsg(i) = tempNext iSTATUS.Text = LoopbackMsgEnd IfEnd Sub。

用VB实现ModbusTCPIP的通讯

Schneider-施耐德LEC使用技巧文集［第7讲］――如何用VB实现Twido的Modbus TCP/IP 的通讯提供:Sch neider-施耐德电气(中国)投资有限公司xx浏览次数：1070Twido系列PLC支持TCPModbus的通讯，尤其是TWDLCAE40DR提供了内置的以太网接口，能实现下图所示的结构；通过HUB,不仅能对Twido进行编程，也能对TwidoPLC中的数据进行读写。

对于TWDLCAE40DRF假定其配置如下：对于上位机，我们利用VB的Win Sock套接字控件能很容易的进行编程。

新建1个套接字对象，设定其属性如右，注意其远程主机的IP就是以上TWDLCAE40DR的IP地址：］1．建立网络连接Private Sub Command2_Click()On Error Resume NextWinsock1.CloseWinsock1.Connect “85.16.1.1 ”, 502If Err ThenMsgBox “网络连接时发生错误:” & Err.Description, vbCriticaI网络连接” E“ClearEnd IfEnd Sub2 .读多个字的命令(本例表示从PLC读％MW3和％MW4两个字)：Private Sub cmdSend_Click()On Error GoTo ErrProcDim SendStr(11) As ByteDim RcvStr() As ByteSendStr(0) = 0 交换'识别号高字节,通常为0SendStr(1) = 0 交换'识别号低字节,通常为0SendStr(2) = 0 协议'识别号高字节,为0SendStr(3) = 0 协议'识别号低字节,为0SendStr(4) = 0字节xx高字节SendStr(5) = 6以下字节xx低字节SendStr(6) = 255 单元'识别号,确省为255 SendStr(7) = &H3 读'多个字命令代码SendStr(8) = 0 读数'据的起始地址高字节SendStr(9) = 3 读数'据的起始地址低字节SendStr(10) = 0数据xx高字节SendStr(11) = 2数据xx低字节Dim aStr As StringDim i As IntegerFor i = 0 To 11aStr = aStr & Chr(SendStr(i))NextWinsock1.SendData aStrExit SubErrProc:MsgBox传输数据失败”，vbCriticaI网络传输“”End Sub3．写多个字的命令(本例表示写%MW3、%MW4、%MW5 三个字到PLCxx)：Private Sub cmdwrite_CIick()On Error GoTo ErrProcDim SendStr(18) As ByteDim RcvStr() As ByteSendStr(0) = 0 交换'识别号高字节,通常为0SendStr(1) = 0 交换'识别号低字节,通常为0 SendStr(2) = 0 协议'识别号高字节,为0SendStr(3) = 0 协议'识别号低字节,为0 SendStr(4) = 0字节xx高字节SendStr(5) = 13以下字节xx低字节SendStr(6) = 255 单元'识别号,确省为255 SendStr(7) = &H10 写多'个字命令代码SendStr(8) = 0 写数'据的起始地址高字节SendStr(9) = 3 写数'据的起始地址低字节SendStr(10) = 0 数据'长度字数的高字节SendStr(11) = 3 数据'长度字数的低字节SendStr(12) = 6数据xx的字节数SendStr(13) = &HA 写的'第1 个字的高字节SendStr(14) = &HB 写的'第1 个字的低字节SendStr(15) = &HC 写的'第2 个字的高字节SendStr(16) = &HD 写的'第2 个字的低字节SendStr(17) = &HE 写的'第3个字的高字节SendStr(18) = &HF 写的'第3 个字的低字节Dim aStr As StringDim i As IntegerFor i = 0 To 18 aStr = aStr & Chr(SendStr(i)) NextWinsock1.SendData aStrExit SubErrProc:MsgBox传输数据失败”，vbCritical,网络传输“”End Sub4．通讯数据处理(本例是得到4 个字节的数据)：Private Sub Winsock1_DataArrival(ByVal bytesTotal As Long) Dim a1, a2, b1, b2, s As StringWinsock1.GetData sIf bytesTotal > 12 Thena1 = Hex$(Asc(Mid$(s, 10, 1)))a2 = Hex$(Asc(Mid$(s, 11, 1)))b1 = Hex$(Asc(Mid$(s, 12, 1)))b2 = Hex$(Asc(Mid$(s, 13, 1)))End IftxtReceive.Text = a1 & a2 & “ // ” & b1 & b2If Len(txtReceive.Text) > 5000 ThentxtReceive.Text = Right(txtReceive.Text, 2000)End IfEnd Sub。

基于VB的MODBUS_RTU通信规约实现办法(1)

基于VB的MODBUS_RTU通信规约实现办法(1)一、MODBUS_RTU通信规约1、通信数据类型及格式标准的MODBUS协议使用串行接口，保护、测控装置（以下称从机，相应称微机为主机）上使用RS-485通信接口，主机上则需要一个RS-232转RS-485转接卡，才能和从机联接。

因此通信信息是标准的串口格式，串行数据字节格式如表1。

表1：串行数据字节格式RTU模式下每个8Bit字节包含两个4Bit的十六进制数字。

这种方式的主要优点是：在同样的波特率下，可比ASCII方式传送更多的数据。

通信数据帧格式如表2。

表2：通信数据帧格式2、地址码和功能码地址码是标识接在同一RS-485总线上不同从机的编号，只有符合地址码的从机才能响应并根据命令回送信息。

地址码是一个字节，从0到255，要求从机地址码不能重复，每个从机只有唯一的地址码。

可定义的功能码为1到127，常用的几个功能码如表3。

表3：常用功能码3、错误校验MODBUS_RTU的数据校验方式采用CRC-16（循环冗余错误校验）其步骤如下：①预置一个16位寄存器为十六进制FFFF，称此寄存器为CRC寄存器。

②把第一个8位二进制数据与CRC低8位字节进行异或运算，将结果放入CRC寄存器。

③把这个16寄存器向右移一位，用0填补最高位，检查移出位。

④若向右移出的数位是0，则返回③，若向右（标记位）移出的数位是1，则CRC寄存器与多项式1010000000000001（A001）进行异或运算。

⑤重复③和④，直至移出8位。

⑥重复②~⑤，进行下一字节处理。

⑦所有字节处理完毕，得到的16位CRC寄存器的高低字节进行交换。

⑧最后得到的CRC寄存器内容即CRC码。

二、VB中串行通信组件设置使用“Microsoft Comm Control 6.0”即MSComm控件，参数设置如图1。

图1：MSComm控件参数设置端口主要参数有端口代号，即串口号，常见的有微机标准配置1和2，其他的号则是由PCI或USB接口转换来的。

Modbus vb源程序(可以读写寄存器)

modbus vb源程序可以读写寄存器自己的项目做完了，最近比较闲，就帮别人用VB写了一个很简单的modbus程序，可以实现实时数据采集显示，以及能对寄存器进行设置。

程序很简单，想用的可以完善，现在只能实时采集显示一个地址的数据，只要修改一下，就可以实时采集多个地址的数据。

现在也只能一次对一个寄存器进行设置，也可以更加完善。

想用的朋友就自己改改吧。

下面是运行界面，采集的模块的地址为75，是一个温湿度采集模块。

有3个寄存器，显示的数据上是温度，湿度，露点温度。

modbusPrivate Sub Command1_Click() '设置按钮Dim bisend() As ByteDim crcDim btLoCRC As Byte, btHiCRC As ByteDim Data As IntegerIf MSComm1.PortOpen = True ThenIf Combo5.ListIndex = 0 ThenReDim bisend(7) '重新定义数组长度bisend(0) = "&h" + Hex(Val(Text1.Text)) '地址码bisend(1) = "&h" + Hex(3) '功能码读寄存器bisend(2) = "&h" + Hex(0) '起始地址高位bisend(3) = "&h" + Hex(0) '起始地址低位bisend(4) = "&h" + Hex(0) '寄存器个数高位bisend(5) = "&h" + Hex(Combo6.ListIndex + 1) '寄存器个数低位crc = CRC16(bisend, 6, btLoCRC, btHiCRC)bisend(6) = "&h" + Hex(btLoCRC) 'CRC高位bisend(7) = "&h" + Hex(btHiCRC) 'CRC低位'发送数据MSComm1.Output = bisendElseReDim bisend(10) '一次只能写一个寄存器bisend(0) = "&h" + Hex(Val(Text1.Text)) '地址码bisend(1) = "&h" + Hex(16) '功能码写寄存器bisend(2) = "&h" + Hex(0) '起始地址高位bisend(3) = "&h" + Hex(0) '起始地址低位bisend(4) = "&h" + Hex(0) '寄存器个数高位bisend(5) = "&h" + Hex(1) '寄存器个数低位bisend(6) = "&h" + Hex(2) '字节数Data = Val(Trim(Text3.Text))bisend(7) = "&h" + Hex(Data \ 256) '要写入寄存器的值的高字节bisend(8) = "&h" + Hex(Data Mod 256) '要写入寄存器的值的低字节crc = CRC16(bisend, 9, btLoCRC, btHiCRC)bisend(9) = "&h" + Hex(btLoCRC) 'CRC高位bisend(10) = "&h" + Hex(btHiCRC) 'CRC低位MSComm1.Output = bisendEnd IfElseMsgBox "串口没有打开"End IfEnd SubPrivate Sub Command2_Click() '实时采集按钮Timer1.Enabled = Not Timer1.Enabled '进行状态切换End SubPrivate Sub Command3_Click()'初始化，并打开串口With MSComm1If .PortOpen = False Then.CommPort = Combo7.ListIndex + 1 '打开串口1.Settings = Combo1.Text + "," + Combo2.Text + "," + Combo3.Text + Combo4.Text.InputMode = 1.InputLen = 50 '一次性从接收缓冲区中读取所有数据(8个字节为一组！！).InBufferCount = 0 '清空接收缓冲区.OutBufferCount = 0 '清空发送缓冲区.RThreshold = 5 + (Combo6.ListIndex + 1) * 2.InBufferSize = 1024.OutBufferSize = 1024.PortOpen = TrueElseMsgBox "串口已经打开"End IfEnd WithEnd SubPrivate Sub Command4_Click() '关闭串口按钮If MSComm1.PortOpen = True Then MSComm1.PortOpen = False End IfEnd SubPrivate Sub Form_Load()Dim i As Integer'波特率设置Combo1.AddItem "4800", 0 Combo1.AddItem "9600", 1 Combo1.AddItem "115200", 2'校验位设置Combo2.AddItem "N", 0Combo2.AddItem "E", 1Combo2.AddItem "O", 2'数据位设置Combo3.AddItem "7", 0Combo3.AddItem "8", 1'停止位设置Combo4.AddItem "1", 0Combo4.AddItem "2", 1'功能码选择Combo5.AddItem "读寄存器03", 0 Combo5.AddItem "写寄存器16", 1 '寄存器个数设置Combo6.AddItem "1", 0Combo6.AddItem "2", 1Combo6.AddItem "3", 2Combo6.AddItem "4", 3Combo6.AddItem "5", 4 Combo6.AddItem "6", 5Combo6.AddItem "7", 6Combo6.AddItem "8", 7Combo6.AddItem "9", 8Combo6.AddItem "10", 9 Combo6.AddItem "11", 10 Combo6.AddItem "12", 11 Combo6.AddItem "13", 12 Combo6.AddItem "14", 13 Combo6.AddItem "15", 14 Combo6.AddItem "16", 15 Combo6.AddItem "17", 16 Combo6.AddItem "18", 17 Combo6.AddItem "19", 18Combo6.AddItem "20", 19Combo6.AddItem "21", 20Combo6.AddItem "22", 21'串口选择Combo7.AddItem "串口1", 0Combo7.AddItem "串口2", 1Combo7.AddItem "串口3", 2Combo7.AddItem "串口4", 3'初始赋值Combo1.ListIndex = 1Combo2.ListIndex = 1Combo3.ListIndex = 1Combo4.ListIndex = 0Combo5.ListIndex = 0Combo6.ListIndex = 2Combo7.ListIndex = 0'初始化串口End SubPrivate Sub Form_Unload(Cancel As Integer)If MSComm1.PortOpen = True ThenMSComm1.PortOpen = FalseEnd IfEnd SubPrivate Sub MSComm1_OnComm()Dim INByte() As ByteDim Buf As StringDim btLoCRC As Byte, btHiCRC As ByteDim Data As IntegerIf mEvent = comEvReceive Then '接收到数据以后INByte = MSComm1.InputIf INByte(1) = 3 Then '读寄存器'CRC校验crc = CRC16(INByte, UBound(INByte) - LBound(INByte) - 1, btLoCRC, btHiCRC)If INByte(UBound(INByte) - 1) = btLoCRC And INByte(UBound(INByte)) = btHiCRC Then '校验正确'////////////////////////////////////For i = 3 To UBound(INByte) - 2 Step 2Data = "&h" + Hex(INByte(i)) + Hex(INByte(i + 1))' Buf = Buf + Hex(INByte(i)) + Chr(32)Buf = Buf + Str(Data) '转换为十进制显示Next iList1.AddItem BufEnd IfEnd IfMSComm1.InBufferCount = 0 '请缓存End IfEnd SubPrivate Sub Timer1_Timer()'定时发送命令Dim tbisend(7) As ByteDim crc '定时1sDim btLoCRC As Byte, btHiCRC As ByteDim Buf As StringIf MSComm1.PortOpen = True Thentbisend(0) = "&h" + Hex(Val(Text1.Text)) '地址码tbisend(1) = "&h" + Hex(3) '功能码读寄存器tbisend(2) = "&h" + Hex(0) '起始地址高位tbisend(3) = "&h" + Hex(0) '起始地址低位tbisend(4) = "&h" + Hex(0) '寄存器个数高位tbisend(5) = "&h" + Hex(Combo6.ListIndex + 1) '寄存器个数低位crc = CRC16(tbisend, 6, btLoCRC, btHiCRC)tbisend(6) = "&h" + Hex(btLoCRC) 'CRC高位tbisend(7) = "&h" + Hex(btHiCRC) 'CRC低位'发送数据MSComm1.Output = tbisendEnd IfEnd Sub////////////////////////////////////////////////////////////////////////////////////////////////////// ///////////////////////////////////////////////////////Function CRC16(Data() As Byte, no As Integer, CRC16Lo As Byte, CRC16Hi As Byte) As StringDim CL As 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 no - 1CRC16Lo = 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CRC16Lo = CRC16Lo \ 2 '低位右移一位If ((SaveHi And &H1) = &H1) Then '如果高位字节最后一位为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 '如果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) = CRC16Hi 'CRC高位ReturnData(1) = CRC16Lo 'CRC低位CRC16 = ReturnDataEnd Function'CRC低位字节值表Function GetCRCLo(ind As Long) As ByteGetCRCLo = Choose(ind + 1, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &HC0, _&H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, &H1, &HC0, _&H80, &H41, &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, _&H0, &HC1, &H81, &H40, &H1, &HC1, &H80, &H41, &H0, &HC1, _&H81, &H40, &H1, &HC0, &H80, &H41, &H1, &HC0, &H80, &H41, _&H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H0, &HC1, _&H81, &H40, &H0, &HC1, &H81, &H40, &H1, &HC0, &H81, &H41, _&H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &HC0, _&H80, &H41, &H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, _&H1, &HC0, &H80, &H41, &H1, &HC0, &H80, &H41, &H0, &HC1, _&H81, &H40, &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, _&H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &HC0, _&H80, &H41, &H0, &HC1, &H81, &H40, &H0, &HC1, &H81,&H40, _&H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, _&H80, &H41, &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, _&H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &HC0, _&H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, _&H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, &H1, &HC0, _&H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, _&H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, _&H80, &H41, &H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, _&H1, &HC0, &H80, &H41, &H1, &HC0, &H80, &H41, &H0, &HC1, _&H81, &H40, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, _&H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &HC0, _&H80, &H41, &H0, &HC1, &H81, &H40)End Function'CRC高位字节值表Function GetCRCHi(ind As Long) As ByteGetCRCHi = Choose(ind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nd Function。

用VB实现Modbus TCPIP的通讯

Schneider-施耐德LEC使用技巧文集[第7讲]——如何用VB实现Twido的Modbus TCP/IP的通讯提供:Schneider-施耐德电气（中国）投资有限公司xx浏览次数：1070Twido系列PLC支持TCPModbus的通讯，尤其是TWDLCAE40DRF提供了内置的以太网接口，能实现下图所示的结构；通过HUB，不仅能对Twido进行编程，也能对TwidoPLC中的数据进行读写。

对于TWDLCAE40DRF，假定其配置如下：对于上位机，我们利用VB的WinSock套接字控件能很容易的进行编程。

新建1个套接字对象，设定其属性如右，注意其远程主机的IP就是以上TWDLCAE40DRF的IP地址：]1．建立网络连接Private Sub Command2_Click()On Error Resume NextWinsock1.CloseWinsock1.Connect “85.16.1.1”, 502If Err ThenMsgBox “网络连接时发生错误:” & Err.Description, vbCritical, “网络连接”Err.ClearEnd IfEnd Sub2．读多个字的命令（本例表示从PLC读%MW3和%MW4两个字）：Private Sub cmdSend_Click()On Error GoTo ErrProcDim SendStr(11) As ByteDim RcvStr() As ByteSendStr(0) = 0 ’交换识别号高字节,通常为0SendStr(1) = 0 ’交换识别号低字节,通常为0SendStr(2) = 0 ’协议识别号高字节,为0SendStr(3) = 0 ’协议识别号低字节,为0SendStr(4) = 0 ’字节xx高字节SendStr(5) = 6 ’以下字节xx低字节SendStr(6) = 255 ’单元识别号,确省为255 SendStr(7) = &H3 ’读多个字命令代码SendStr(8) = 0 ’读数据的起始地址高字节SendStr(9) = 3 ’读数据的起始地址低字节SendStr(10) = 0 ’数据xx高字节SendStr(11) = 2 ’数据xx低字节Dim aStr As StringDim i As IntegerFor i = 0 To 11aStr = aStr & Chr(SendStr(i))NextWinsock1.SendData aStrExit SubMsgBox “传输数据失败”, vbCritical, “网络传输”End Sub3．写多个字的命令（本例表示写%MW3、%MW4、%MW5三个字到PLCxx）：Private Sub cmdwrite_Click()On Error GoTo ErrProcDim SendStr(18) As ByteDim RcvStr() As ByteSendStr(0) = 0 ’交换识别号高字节,通常为0SendStr(1) = 0 ’交换识别号低字节,通常为0SendStr(2) = 0 ’协议识别号高字节,为0SendStr(3) = 0 ’协议识别号低字节,为0SendStr(4) = 0 ’字节xx高字节(5) = 13 ’以下字节xx低字节SendStr(6) = 255 ’单元识别号,确省为255 SendStr(7) = &H10 ’写多个字命令代码SendStr(8) = 0 ’写数据的起始地址高字节SendStr(9) = 3 ’写数据的起始地址低字节SendStr(10) = 0 ’数据长度字数的高字节SendStr(11) = 3 ’数据长度字数的低字节SendStr(12) = 6 ’数据xx的字节数SendStr(13) = &HA ’写的第1个字的高字节SendStr(14) = &HB ’写的第1个字的低字节SendStr(15) = &HC ’写的第2个字的高字节SendStr(16) = &HD ’写的第2个字的低字节SendStr(17) = &HE ’写的第3个字的高字节SendStr(18) = &HF ’写的第3个字的低字节Dim aStr As StringDim i As IntegerFor i = 0 To 18aStr = aStr & Chr(SendStr(i))NextWinsock1.SendData aStrExit SubErrProc:MsgBox “传输数据失败”, vbCritical, “网络传输”End Sub4．通讯数据处理（本例是得到4个字节的数据）：Private Sub Winsock1_DataArrival(ByVal bytesTotal As Long) Dim a1, a2, b1, b2, s As StringWinsock1.GetData sIf bytesTotal > 12 Thena1 = Hex$(Asc(Mid$(s, 10, 1)))a2 = Hex$(Asc(Mid$(s, 11, 1)))b1 = Hex$(Asc(Mid$(s, 12, 1)))b2 = Hex$(Asc(Mid$(s, 13, 1)))End IftxtReceive.Text = a1 & a2 & “//” & b1 & b2If Len(txtReceive.Text) > 5000 Then txtReceive.Text = Right(txtReceive.Text, 2000) End IfEnd Sub。

Modbusvb源程序可以读写寄存器

Modbus-vb源程序(可以读写寄存器)modbus vb源程序可以读写寄存器自己的项目做完了，最近比较闲，就帮别人用VB写了一个很简单的modbus程序，可以实现实时数据采集显示，以及能对寄存器进行设置。

程序很简单，想用的可以完善，现在只能实时采集显示一个地址的数据，只要修改一下，就可以实时采集多个地址的数据。

现在也只能一次对一个寄存器进行设置，也可以更加完善。

想用的朋友就自己改改吧。

下面是运行界面，采集的模块的地址为75，是一个温湿度采集模块。

有3个寄存器，显示的数据上是温度，湿度，露点温度。

modbusPrivate Sub Command1_Click() '设置按钮Dim bisend() As ByteDim crcDim btLoCRC As Byte, btHiCRC As Byte Dim Data As IntegerIf MSComm1.PortOpen = True ThenIf Combo5.ListIndex = 0 ThenReDim bisend(7) '重新定义数组长度 bisend(0) = "&h" + Hex(Val(Text1.Text)) '地址码bisend(1) = "&h" + Hex(3) '功能码读寄存器bisend(2) = "&h" + Hex(0) '起始地址高位bisend(3) = "&h" + Hex(0) '起始地址低位bisend(4) = "&h" + Hex(0) '寄存器个数高位bisend(5) = "&h" + Hex(Combo6.ListIndex + 1) '寄存器个数低位 crc = CRC16(bisend, 6, btLoCRC, btHiCRC)bisend(6) = "&h" + Hex(btLoCRC)'CRC高位bisend(7) = "&h" + Hex(btHiCRC) 'CRC低位'发送数据MSComm1.Output = bisendElseReDim bisend(10) '一次只能写一个寄存器bisend(0) = "&h" + Hex(Val(Text1.Text)) '地址码bisend(1) = "&h" + Hex(16) '功能码写寄存器bisend(2) = "&h" + Hex(0) '起始地址高位bisend(3) = "&h" + Hex(0) '起始地址低位bisend(4) = "&h" + Hex(0) '寄存器个数高位bisend(5) = "&h" + Hex(1) '寄存器个数低位bisend(6) = "&h" + Hex(2) '字节数Data = Val(Trim(Text3.Text))bisend(7) = "&h" + Hex(Data \ 256) '要写入寄存器的值的高字节bisend(8) = "&h" + Hex(Data Mod 256) '要写入寄存器的值的低字节crc = CRC16(bisend, 9, btLoCRC, btHiCRC)bisend(9) = "&h" + Hex(btLoCRC) 'CRC高位bisend(10) = "&h" + Hex(btHiCRC) 'CRC低位MSComm1.Output = bisendEnd IfElseMsgBox "串口没有打开"End IfEnd SubPrivate Sub Command2_Click() '实时采集按钮Timer1.Enabled = Not Timer1.Enabled '进行状态切换End SubPrivate Sub Command3_Click()'初始化，并打开串口With MSComm1If .PortOpen = False Then.CommPort = Combo7.ListIndex + 1 '打开串口1.Settings = Combo1.Text + "," +Combo2.Text + "," + Combo3.Text +Combo4.Text.InputMode = 1.InputLen = 50 '一次性从接收缓冲区中读取所有数据(8个字节为一组！！).InBufferCount = 0 '清空接收缓冲区.OutBufferCount = 0 '清空发送缓冲区.RThreshold = 5 + (Combo6.ListIndex +1) * 2.InBufferSize = 1024.OutBufferSize = 1024.PortOpen = TrueElseMsgBox "串口已经打开"End IfEnd WithEnd SubPrivate Sub Command4_Click() '关闭串口按钮If MSComm1.PortOpen = True ThenMSComm1.PortOpen = FalseEnd IfEnd SubPrivate Sub Form_Load()Dim i As Integer'波特率设置Combo1.AddItem "4800", 0Combo1.AddItem "9600", 1Combo1.AddItem "115200", 2'校验位设置Combo2.AddItem "N", 0Combo2.AddItem "E", 1Combo2.AddItem "O", 2'数据位设置Combo3.AddItem "7", 0Combo3.AddItem "8", 1'停止位设置Combo4.AddItem "1", 0Combo4.AddItem "2", 1'功能码选择Combo5.AddItem "读寄存器03", 0 Combo5.AddItem "写寄存器16", 1 '寄存器个数设置Combo6.AddItem "1", 0Combo6.AddItem "2", 1Combo6.AddItem "3", 2Combo6.AddItem "4", 3Combo6.AddItem "5", 4Combo6.AddItem "6", 5Combo6.AddItem "7", 6Combo6.AddItem "8", 7Combo6.AddItem "9", 8Combo6.AddItem "10", 9Combo6.AddItem "11", 10Combo6.AddItem "12", 11Combo6.AddItem "13", 12Combo6.AddItem "14", 13Combo6.AddItem "15", 14 Combo6.AddItem "16", 15Combo6.AddItem "17", 16Combo6.AddItem "18", 17Combo6.AddItem "19", 18Combo6.AddItem "20", 19Combo6.AddItem "21", 20 Combo6.AddItem "22", 21'串口选择Combo7.AddItem "串口1", 0 Combo7.AddItem "串口2", 1 Combo7.AddItem "串口3", 2 Combo7.AddItem "串口4", 3'初始赋值Combo1.ListIndex = 1 Combo2.ListIndex = 1 Combo3.ListIndex = 1 Combo4.ListIndex = 0 Combo5.ListIndex = 0Combo6.ListIndex = 2Combo7.ListIndex = 0'初始化串口End SubPrivate Sub Form_Unload(Cancel As Integer)If MSComm1.PortOpen = True ThenMSComm1.PortOpen = FalseEnd IfEnd SubPrivate Sub MSComm1_OnComm()Dim INByte() As ByteDim Buf As StringDim btLoCRC As Byte, btHiCRC As ByteDim Data As IntegerIf mEvent = comEvReceive Then '接收到数据以后INByte = MSComm1.InputIf INByte(1) = 3 Then '读寄存器'CRC校验crc = CRC16(INByte, UBound(INByte) - LBound(INByte) - 1, btLoCRC, btHiCRC)If INByte(UBound(INByte) - 1) = btLoCRC And INByte(UBound(INByte)) = btHiCRC Then'校验正确'////////////////////////////////////For i = 3 To UBound(INByte) - 2 Step 2Data = "&h" + Hex(INByte(i)) + Hex(INByte(i + 1))' Buf = Buf + Hex(INByte(i)) + Chr(32) Buf = Buf + Str(Data) '转换为十进制显示Next iList1.AddItem BufEnd IfEnd IfMSComm1.InBufferCount = 0 '请缓存End IfEnd SubPrivate Sub Timer1_Timer()'定时发送命令Dim tbisend(7) As ByteDim crc '定时1sDim btLoCRC As Byte, btHiCRC As ByteDim Buf As StringIf MSComm1.PortOpen = True Thentbisend(0) = "&h" + Hex(Val(Text1.Text)) '地址码tbisend(1) = "&h" + Hex(3) '功能码读寄存器tbisend(2) = "&h" + Hex(0) '起始地址高位tbisend(3) = "&h" + Hex(0) '起始地址低位tbisend(4) = "&h" + Hex(0) '寄存器个数高位tbisend(5) = "&h" + Hex(Combo6.ListIndex + 1) '寄存器个数低位 crc = CRC16(tbisend, 6, btLoCRC, btHiCRC)tbisend(6) = "&h" + Hex(btLoCRC)'CRC高位tbisend(7) = "&h" + Hex(btHiCRC)'CRC低位'发送数据MSComm1.Output = tbisendEnd IfEnd Sub/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////Function CRC16(Data() As Byte, no As Integer,CRC16Lo As Byte, CRC16Hi As Byte) As StringDim CL As 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 no - 1CRC16Lo = 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CRC16Lo = CRC16Lo \ 2 '低位右移一位If ((SaveHi And &H1) = &H1) Then'如果高位字节最后一位为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'如果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) = CRC16Hi 'CRC高位ReturnData(1) = CRC16Lo 'CRC低位CRC16 = ReturnDataEnd Function'CRC低位字节值表Function GetCRCLo(ind As Long) As ByteGetCRCLo = Choose(ind + 1, &H0, &HC1, &H81,&H40, &H1, &HC0, &H80, &H41, &H1, &HC0, _&H0, &HC1,&H81, &H40, &H0, &HC1, &H81, &H40, &H1, &HC0,_&H80, &H41, &H1,&HC0, &H80, &H41, &H0, &HC1, &H81, &H40, _&H0, &HC1, &H81,&H40, &H1, &HC1, &H80, &H41, &H0, &HC1, _&H81, &H40, &H1,&HC0, &H80, &H41, &H1, &HC0, &H80, &H41, _ &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H0, &HC1, _ &H81, &H40, &H0, &HC1, &H81, &H40, &H1, &HC0, &H81, &H41, _ &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &HC0, _ &H80, &H41, &H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, _ &H1, &HC0, &H80, &H41, &H1, &HC0, &H80, &H41, &H0, &HC1, _ &H81, &H40, &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, _ &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &HC0, _ &H80, &H41, &H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, _ &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, _ &H80, &H41, &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, _ &H0, &HC1, &H81,&H40, &H1, &HC0, &H80, &H41, &H1, &HC0, _ &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, _ &H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, &H1, &HC0, _ &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, _ &H1, &HC0, &H80, &H41, &H0, &HC1, &H81, &H40, &H1, &HC0, _ &H80, &H41, &H0, &HC1, &H81, &H40, &H0, &HC1, &H81, &H40, _ &H1, &HC0, &H80, &H41, &H1, &HC0, &H80, &H41, &H0, &HC1, _ &H81, &H40, &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, _ &H0, &HC1, &H81, &H40, &H1, &HC0, &H80, &H41, &H1, &HC0, _ &H80, &H41, &H0, &HC1, &H81, &H40)End Function'CRC高位字节值表Function GetCRCHi(ind As Long) As ByteGetCRCHi = Choose(ind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nd Function。

VB编写的ModbusRTU协议范文通讯源程序

VB编写的ModbusRTU协议范文通讯源程序modburtu协议可以算是一种事实上的工业标准协议，为许多仪表、PLC等所支持。

以前有几个用户问如何使用VB编程来与我们的KND-K3系列PLC通讯，于是整了一个demo程序。

这次把这个demo共享，希望能给大家一点帮助。

1）模块文件：modCRC，其中包含了CRC校验的函数。

'data待校验的数组名称'no数组中元素个数'btLoCRC算出的CRC高字节'btHiCRC算出的CRC低字节PublicFunctionCalCRC16Fat(data()AByte,noAInteger,btLoCRCAByt e,btHiCRCAByte)AStringDimCLAByte,CHAByte'多项式码&HA001DimSaveHiAByte,SaveLoAByteDimiAIntegerDimFlagAInteger btHiCRC=&HFFbtLoCRC=&HFFCL=&H1CH=&HA0Fori=0To(no-1)btHiCRC=btHiCRC某ordata(i)'每一个数据与CRC寄存器进行异或ForFlag=0To7SaveHi=btLoCRCSaveLo=btHiCRCbtLoCRC=btLoCRC\\2'高位右移一位btHiCRC=btHiCRC\\2'低位右移一位If((SaveHiAnd&H1)=&H1)Then'如果高位字节最后一位为1btHiCRC=btHiCRCOr&H80'则低位字节右移后前面补1EndIf'否则自动补0If((SaveLoAnd&H1)=&H1)Then'如果LSB为1，则与多项式码进行异或btLoCRC=btLoCRC某orCHbtHiCRC=btHiCRC某orCLEndIfNe某tFlagNe某tiDimReturnData(1)AByteReturnData(0)=btHiCRC'CRC高位ReturnData(1)=btLoCRC'CRC低位CalCRC16Fat=ReturnDataEndFunctionPublicFunctionCalCRC16Tbl(data()AByte,noAInteger,btLoCRCAByt e,btHiCRCAByte)AStringDimbtLoCRCAByteDimbtHiCRCABytebtLoCRC=&HFFbtHiCRC=&HFFDimiAIntegerDimiInde某ALongFori=0To(no-1)iInde某=btHiCRC某ordata(i)btHiCRC=btLoCRC某orGetCRCLo(iInde某)'低位处理btLoCRC=GetCRCHi(iInde某)'高位处理Ne某tiDimReturnData(1)AByteReturnData(0)=btHiCRC'CRC高位ReturnData(1)=btLoCRC'CRC低位CalCRC16Tbl=ReturnDataEndFunction'CRC低位字节值表FunctionGetCRCLo(IndALong)AByteGetCRCLo=Chooe(Ind+1,_&H0,&HC1,&H81,&H40,&H1,&HC0,&H80,&H41,&H1,&HC0,_&H80,&H41,&H 0,&HC1,&H81,&H40,&H1,&HC0,&H80,&H41,_&H0,&HC1,&H81,&H40,&H0,&HC1 ,&H81,&H40,&H1,&HC0,_&H80,&H41,&H1,&HC0,&H80,&H41,&H0,&HC1,&H81, &H40,_&H0,&HC1,&H81,&H40,&H1,&HC0,&H80,&H41,&H0,&HC1,_&H81,&H40, &H1,&HC0,&H80,&H41,&H1,&HC0,&H80,&H41,_&H0,&HC1,&H81,&H40,&H1,&H C0,&H80,&H41,&H0,&HC1,_&H81,&H40,&H0,&HC1,&H81,&H40,&H1,&HC0,&H8 0,&H41,_&H0,&HC1,&H81,&H40,&H1,&HC0,&H80,&H41,&H1,&HC0,_&H80,&H4 1,&H0,&HC1,&H81,&H40,&H0,&HC1,&H81,&H40,_&H1,&HC0,&H80,&H41,&H1, &HC0,&H80,&H41,&H0,&HC1,_&H81,&H40,&H1,&HC0,&H80,&H41,&H0,&HC1,& H81,&H40,_&H0,&HC1,&H81,&H40,&H1,&HC0,&H80,&H41,&H1,&HC0,_&H80,& H41,&H0,&HC1,&H81,&H40,&H0,&HC1,&H81,&H40,_&H1,&HC0,&H80,&H41,&H 0,&HC1,&H81,&H40,&H1,&HC0,_&H80,&H41,&H1,&HC0,&H80,&H41,&H0,&HC1 ,&H81,&H40,_&H0,&HC1,&H81,&H40,&H1,&HC0,&H80,&H41,&H1,&HC0,_&H80 ,&H41,&H0,&HC1,&H81,&H40,&H1,&HC0,&H80,&H41,_&H0,&HC1,&H81,&H40, &H0,&HC1,&H81,&H40,&H1,&HC0,_&H80,&H41,&H0,&HC1,&H81,&H40,&H1,&H C0,&H80,&H41,_&H1,&HC0,&H80,&H41,&H0,&HC1,&H81,&H40,&H1,&HC0,_&H 80,&H41,&H0,&HC1,&H81,&H40,&H0,&HC1,&H81,&H40,_&H1,&HC0,&H80,&H4 1,&H1,&HC0,&H80,&H41,&H0,&HC1,_&H81,&H40,&H0,&HC1,&H81,&H40,&H1,&HC0,&H80,&H41,&H0,&HC1,&H8 1,&H40,&H1,&HC0,&H80,&H41,&H1,&HC0,&H80,&H41,&H0,&HC1,&H81,&H40) EndFunction'CRC高位字节值表FunctionGetCRCHi(IndALong)AByteGetCRCHi=Chooe(Ind+1,_&H0,&HC0,&HC1,&H1,&HC3,&H3,&H2,&HC2,&HC6,&H6,&H7,&HC7,&H5,&H C5,&HC4,&H4,&HCC,&HC,&HD,&HCD,&HF,&HCF,&HCE,&HE,&HA,&HCA,&HCB,&H B,&HC9,&H9,&H8,&HC8,&HD8,&H18,&H19,&HD9,&H1B,&HDB,&HDA,&H1A,&H1E ,&HDE,&HDF,&H1F,&HDD,&H1D,&H1C,&HDC,&H14,&HD4,&HD5,&H15,&HD7,&H1 7,&H16,&HD6,&HD2,&H12,&H13,&HD3,&H11,&HD1,&HD0,&H10,&HF0,&H30,&H 31,&HF1,&H33,&HF3,&HF2,&H32,&H36,&HF6,&HF7,&H37,&HF5,&H35,&H34,& HF4,&H3C,&HFC,&HFD,&H3D,&HFF,&H3F,&H3E,&HFE,&HFA,&H3A,&H3B,&HFB, &H39,&HF9,&HF8,&H38,&H28,&HE8,&HE9,&H29,&HEB,&H2B,&H2A,&HEA,&HEE,&H2E,&H2F,&HEF,&H2D,&HED,&HEC,&H2C,&H E4,&H24,&H25,&HE5,&H27,&HE7,&HE6,&H26,&H22,&HE2,&HE3,&H23,&HE1,& H21,&H20,&HE0,&HA0,&H60,_&H61,&HA1,&H63,&HA3,&HA2,&H62,&H66,&HA6,&HA7,&H67,&HA5,&H65, &H64,&HA4,&H6C,&HAC,&HAD,&H6D,&HAF,&H6F,&H6E,&HAE,&HAA,&H6A,&H6B ,&HAB,&H69,&HA9,&HA8,&H68,&H78,&HB8,&HB9,&H79,&HBB,&H7B,&H7A,&HB A,&HBE,&H7E,&H7F,&HBF,&H7D,&HBD,&HBC,&H7C,&HB4,&H74,&H75,&HB5,&H 77,&HB7,&HB6,&H76,&H72,&HB2,&HB3,&H73,&HB1,&H71,&H70,&HB0,&H50,& H90,&H91,&H51,&H93,&H53,&H52,&H92,&H96,&H56,&H57,&H97,&H55,&H95,&H94,&H54,&H9C,&H5C,&H5D,&H9D,&H5F,&H9F,&H9E,&H5E,&H5A,&H9A,&H9B ,&H5B,&H99,&H59,&H58,&H98,&H88,&H48,&H49,&H89,&H4B,&H8B,&H8A,&H4 A,&H4E,&H8E,&H8F,&H4F,&H8D,&H4D,&H4C,&H8C,&H44,&H84,&H85,&H45,&H 87,&H47,&H46,&H86,&H82,&H42,&H43,&H83,&H41,&H81,&H80,&H40) EndFunctionBeginVB.Te某tBo某t某tReceive注：放置接收上来的IB0数据Height=495Left=1200TabInde某=2Top=2280Width=1335EndCaption=\置位Q1.1\Height=495Left=2160TabInde某=0Top=3720Width=1575End①Form_Load事件，在此主要是实现了打开并初始化串口PrivateSubForm_Load().Setting=\If(Not.PortOpen)Then.PortOpen=TrueEndWithEndSub②Form_UnLoad事件，在此主要是关闭串口PrivateSubForm_Unload(CancelAInteger)EndSub③“置位Q1.1”按钮单击事件'设置Q1.1为1PrivateSubcmdSDO_Click()DimbtSend(8)ABytebtSend(0)=&H1'目标站号btSend(1)=&H5'功能码btSend(2)=&H0'Q1.1地址（0009）高字节btSend(3)=&H9'Q1.1地址（0009）低字节btSend(4)=&HFF'强制值高字节btSend(5)=&H0'强制值低字节DimcrcDimbtCRCHiAByte,btCRCLoABytecrc=CalCRC16Fat(btSend,6,btCRCLo,btCRCHi)btSend(6)=btCRCHibtSend(7)=btCRCLoEndSub④“读取IB0”按钮单击事件'发请求DimbtSend(8)ABytebtSend(0)=&H1'目标站号btSend(1)=&H2'功能码btSend(2)=&H0'I0.0地址（0000）高字节btSend(3)=&H0'i0.0地址（0000）低字节btSend(4)=&H0'读取个数高字节btSend(5)=&H8'读取个数低字节DimcrcDimbtCRCHiAByte,btCRCLoABytecrc=CalCRC16Fat(btSend,6,btCRCLo,btCRCHi)btSend(6)=btCRCHibtSend(7)=btCRCLo'注意下面编写的接收过程很简单，要编写实际应用的监控程序来说需要更完善DimbtReceiveAVariantDoEventLoopUntil.InBufferCount=6.InputLen=6btReceive=.InputIfbtReceive(1)=&H2Then'若正确，返回帧的第2个字节为功能码.实际上，此处应首先进行CRC校验t某tReceive.Te某t=He某$(btReceive(3))EndIfEndWithEndSub。