RT，小弟由于剛接觸VB不久，用VB6.0與FX2N通訊，向PLC的D寫(xiě)入值老是不對(duì)，不知道是不是格式不對(duì)，我是利用MSComm控件通訊的。。。outstring = Chr(&O2) + "1" + CStr(qiuhe) + "02" + CStr(xieru) + Chr(&O3) + hejiaoyan

Private Sub Command1_Click()      '寫(xiě)入D0=0
Dim Address As String
Dim SenData As String

MSComm1.Settings = "9600,E,7,1"              
MSComm1.InputMode = comInputModeText

Address = "1" + "1000" + "02" + "0000" + Chr(3)
SenData = Chr(2) & Address & SumChk(Address)
MSComm1.PortOpen = True
MSComm1.Output = SenData
End Sub

Private Function SumChk(Dats$) As String                  'CheckSum
    Dim i&
    Dim CHK&
    For i = 1 To Len(Dats)
        CHK = CHK + Asc(Mid(Dats, i, 1))
    Next i
    SumChk = Right(Hex$(CHK), 2)
End Function

寫(xiě)入的數(shù)據(jù)16進(jìn)制數(shù)據(jù), 是先寫(xiě)低字節(jié), .再寫(xiě)高字節(jié).
因此如寫(xiě)"1"進(jìn)去PLC, 應(yīng)寫(xiě)成"0100", 寫(xiě)"255"進(jìn)去PLC, 應(yīng)寫(xiě)成"FF00"

‘可用數(shù)組變量
Dim strText(10) As String

Private Sub Form_Load()
For i = 0 To 10
    strText(i) = Text1.Text & i
    List1.AddItem strText(i)
Next i

End Sub