modbus vb源程序可以读写寄存器_PLC入门

modbus vb源程序可以读写寄存器

点击数：7773 次录入时间：03-04 12:01:37 整理：http://www.55dianzi.com PLC入门

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。

modbus

Private Sub Command1_Click() '设置按钮
        Dim bisend() As Byte
        Dim crc
        Dim btLoCRC As Byte, btHiCRC As Byte
        Dim Data As Integer
    If MSComm1.PortOpen = True Then
       If Combo5.ListIndex = 0 Then
         ReDim 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 = bisend
       Else
        ReDim 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 = bisend
       End If
   Else
     MsgBox "串口没有打开"
End If
End Sub

Private Sub Command2_Click() '实时采集按钮
Timer1.Enabled = Not Timer1.Enabled '进行状态切换
End Sub

Private Sub Command3_Click()
'初始化，并打开串口
With MSComm1
     If .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 = True
    Else
     MsgBox "串口已经打开"
    End If
End With

End Sub

Private Sub Command4_Click() '关闭串口按钮
If MSComm1.PortOpen = True Then
MSComm1.PortOpen = False
End If
End Sub

Private 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", 0
Combo2.AddItem "E", 1
Combo2.AddItem "O", 2

'数据位设置

Combo3.AddItem "7", 0
Combo3.AddItem "8", 1

'停止位设置

Combo4.AddItem "1", 0
Combo4.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", 0
Combo6.AddItem "2", 1
Combo6.AddItem "3", 2
Combo6.AddItem "4", 3
Combo6.AddItem "5", 4
Combo6.AddItem "6", 5
Combo6.AddItem "7", 6
Combo6.AddItem "8", 7
Combo6.AddItem "9", 8
Combo6.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", 18
Combo6.AddItem "20", 19
Combo6.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 = 0
Combo6.ListIndex = 2
Combo7.ListIndex = 0
'初始化串口
End Sub

Private Sub Form_Unload(Cancel As Integer)
If MSComm1.PortOpen = True Then
MSComm1.PortOpen = False
End If
End Sub

Private Sub MSComm1_OnComm()
Dim INByte() As Byte
Dim Buf As String
Dim btLoCRC As Byte, btHiCRC As Byte
Dim Data As Integer
If MSComm1.CommEvent = comEvReceive Then       '接收到数据以后
INByte = MSComm1.Input
    If INByte(1) = 3 Then '读寄存器
       'CRC校验
      crc = CRC16(INByte, UBound(INByte) - LBound(INByte) - 1, btLoCRC, btHiCRC)

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