modbus ascii协议vb程序用mscomm控件核心通讯程序源代码.txt

我用vb编写modbus协议,拿出来与大家分享一下

Dim B$

Private Sub end_Click()
MSComm1.PortOpen = False
End
End Sub


Private Sub clr_Click()
receve.Text = ""
End Sub

Private Sub inputc_Change()

End Sub

Private Sub send_Click()
MSComm1.Output = B$ & Chr(13) & Chr(10)
End Sub

Private Sub lrc_Click()
Dim A$
Dim ee

A = inputc.Text

   For j = 2 To Len(A) Step 2
    ee = ee + Val("&h" + Mid(A, j, 2))
   Next j
   
B = A + Hex((256 - (ee And &HFF)))

outputc.Text = B
End Sub

Private Sub Form_Load()
MSComm1.PortOpen = True
MSComm1.Settings = "9600,e,7,1"
Timer1.Interval = 500
End Sub

 

Private Sub Timer1_Timer()
If MSComm1.InBufferCount > 0 Then
receve.Text = receve.Text + MSComm1.Input
End If


End Sub