VB和台达可编程逻辑控制器plc上位机 通讯软件.doc

为答谢各位网友的支持,也算是一个小小的礼物吧,特将我以VB写的
一个工控通讯程序源码奉上,以资感谢.
 这个程序是VB同台达PLC的通讯调试程序,其于台达系列PLC的
MODBUS ASCII协议,涉及IO及寄存器的读写,稍加改动即可用于
,也参考了<<基于VB 的台达PLC和
监控计算机的串口通讯>>一文,在此也向作者表示感谢.
 
Dim plc As Byte
Dim y0flag As Byte
Dim y1flag As Byte
Dim str As String
Dim n, S
Private mand1_Click()
Dim strout As String
Dim QQ As String
= False
QQ =
If Len(QQ) = 3 Then
        QQ = "0" & QQ
    ElseIf Len(QQ) = 2 Then
        QQ = "00" & QQ
    ElseIf Len(QQ) = 1 Then
        QQ = "000" & QQ
End If
str = "01061000" + QQ
= LRC(str)   '计算 str的lrc校验码。
strout = ":" + str + + Chr$(13) + Chr$(10) '欲传送之数据。13为D,10为A
= 0
= strout
= True
End Sub
Private mand2_Click()
End Sub
Private Sub Form_Load()
    Dim s1 As String
    Dim s2 As String
    Dim s22 As String
    Dim s3 As String
    Dim s4 As String
   
    0, 0, 5600, 280   '长度可随意改
    = True
    n = -((Now)) - 10
    = True
    = True
    s2 = "01010C300001"
    s22 = LRC(s2)
    s1 = ":" + s2 + s22 + Chr$(13) + Chr$(10)
    = 0
    = s1
    TimeDelay (500)
    s3 =
    s4 = Mid$(s3, 8, 2)
    If s4 = "31" Then
        plc = 1
    Else: If s4 = "30" Then plc = 0
    End If
    If plc = 1 Then
        = "