Private Sub Form_Load()
MSComm1.CommPort = 1
MSComm1.Settings = "9600,e,7,1"
MSComm1.InputLen = 0
MSComm1.PortOpen = True
End Sub
Private Sub Command1_Click()
Dim a, av As String
a = "0010002" + Chr(3)
MSComm1.Output = Chr(5) + Chr(2) + a+ sumcheck(a)
av = MSComm1.Input
Print av
End Sub
为什么什么也接受不到,没有反应,清高手指点

去这贴子看一下：贴子主题： 請教高人，關於VB與PLC通信的問題(以下是我的代碼)!

Private Sub Form_Load()
MSComm1.CommPort = 1
MSComm1.Settings = "9600,e,7,1"
MSComm1.InputLen = 0
MSComm1.PortOpen = True
End Sub
Private Sub Command1_Click()
Dim a, av As String
a = "0010002" + Chr(3)
MSComm1.Output = Chr(5) + Chr(2) + a+ sumcheck(a)
'以上這句改為:MSComm1.Output = Chr(2) + a+ sumcheck(a)即可!
av = MSComm1.Input
Print av
End Sub

三菱FX系列PLC编程口通信(用VB中的专用控件）为什么总是不行呀，请哪位高人指点下！