VB编的程序与欧姆龙的PLC CPM1A通信，出错提示：实时错误13 ，类型不匹配，请高手看一下我的程序！

我用VB编的程序与欧姆龙的PLC CPM1A通信，目的读取DM存储区的数据，我用了6个TIMER时钟，但是在我运行时总是出错提示：实时错误13 ，类型不匹配。我怀疑是这6个时钟的循环时间设置的问题，有没有高手告诉我问题在哪啊！我的邮箱zhangyongliangaaa@126.com
程序如下：
Dim tim As Integer
Private Sub Command1_Click()
Dim outstring As String
MSComm1.InBufferCount = 0
   outstring = "@" + "00" + "SC" + "03"
   fcdd$ = XORR(outstring)
   outstring = outstring + fcdd$ + "*" + Chr$(13)
   MSComm1.Output = outstring
   
   Time_out = tim
    Do
      If tim > (Time_out + 1) Then
        ERROR_COM = True
      Else
        ERROR_COM = False
      End If
      DoEvents
    Loop Until ((MSComm1.InBufferCount >= 11) Or (ERROR_COM = True))
     Instring = MSComm1.Input
     endcode = Mid(Instring, 6, 2)
     Call ErrMessage(endcode)
End Sub
Private Sub Command2_Click()
Dim outstring As String
 
MSComm1.InBufferCount = 0
   outstring = "@" + "00" + "SC" + "00"
   fcdd$ = XORR(outstring)
   outstring = outstring + fcdd$ + "*" + Chr$(13)
   MSComm1.Output = outstring
   
   Time_out = tim
    Do
      If tim > (Time_out + 1) Then
        ERROR_COM = True
      Else
        ERROR_COM = False
      End If
      DoEvents
    Loop Until ((MSComm1.InBufferCount >= 11) Or (ERROR_COM = True))
     Instring = MSComm1.Input
     endcode = Mid(Instring, 6, 2)
     Call ErrMessage(endcode)
End Sub



Private Sub Command3_Click()
Dim outstring As String

   MSComm1.InBufferCount = 0
   outstring = "@" + "00" + "WD" + "0012" + Text2.Text
   fcdd$ = XORR(outstring)
   outstring = outstring + fcdd$ + "*" + Chr$(13)
   MSComm1.Output = outstring
   
   Time_out = tim
    Do
      If tim > (Time_out + 1) Then
        ERROR_COM = True
      Else
        ERROR_COM = False
      End If
      DoEvents
    Loop Until ((MSComm1.InBufferCount >= 11) Or (ERROR_COM = True))
     Instring = MSComm1.Input
     endcode = Mid(Instring, 6, 2)
     Call ErrMessage(endcode)
End Sub

Private Sub Command4_Click()
Dim outstring As String

   MSComm1.InBufferCount = 0
   outstring = "@" + "00" + "WD" + "0036" + (Text2.Text / 0.099695)
   fcdd$ = XORR(outstring)
   outstring = outstring + fcdd$ + "*" + Chr$(13)
   MSComm1.Output = outstring
   
   Time_out = tim
    Do
      If tim > (Time_out + 1) Then
        ERROR_COM = True
      Else
        ERROR_COM = False
      End If
      DoEvents
    Loop Until ((MSComm1.InBufferCount >= 11) Or (ERROR_COM = True))
     Instring = MSComm1.Input
     endcode = Mid(Instring, 6, 2)
     Call ErrMessage(endcode)
End Sub

Private Sub Command5_Click()
End

End Sub

Private Sub Form_Load()         '初始化
  Caption = "Form1"
  ClientHeight = 4095
  ClientLeft = 60
  ClientTop = 345
  ClientWidth = 4275
  LinkTopic = "Form1"
  ScaleHeight = 4095
  ScaleWidth = 4275
tim = 0
 Call INIT_comm
End Sub
Public Sub INIT_comm()
 'Buffer to hold input string
 Dim Instring, outstring As String
   MSComm1.CommPort = 1   'Use COM1.
   MSComm1.Settings = "9600,e,7,2"  '9600 baud, e parity, 7 data, and 2 stop bit.
   MSComm1.InputLen = 0   'Tell the control to read entire buffer when Input
   MSComm1.PortOpen = True   'Open the port.
End Sub



Private Sub Timer1_Timer()
Dim outstring As String

 MSComm1.InBufferCount = 0 'clear off  inbuffer
   outstring = "@" + "00" + "RD" + "0010" + "0011"
   fcdd$ = XORR(outstring)
   outstring = outstring + fcdd$ + "*" + Chr$(13)
   MSComm1.Output = outstring
   Time_out = tim
   
  '判断通讯错误
   Do
     If tim > (Time_out + 1) Then
       ERROR_COM = True
     Else
       ERROR_COM = False
     End If
       DoEvents
   Loop Until ((MSComm1.InBufferCount >= 11 + 4 * Lengh) Or (ERROR_COM = True))
   
   Instring = MSComm1.Input
   order1 = Mid(Instring, 6, 2)  '结束码
   Call ErrMessage(order1)
     Text1.Text = Mid(Instring, 8, 4) * 0.099695  '取出数据位
End Sub

Private Sub Timer2_Timer()
tim = tim + 1
End Sub
Public Function ErrMessage(ByVal X As String)
 Select Case X
   Case "13"
     MsgBox "校验错误"
   Case "14"
     MsgBox "格式错误"
   Case "15"
     MsgBox "入口码错误"
   Case "18"
     MsgBox "帧长度错误"
   Case "A3"
     MsgBox "传送数据时因FCS错误引起终止"
   Case "A8"
     MsgBox "传送数据时因长度错误引起在终止"
 End Select
End Function
Function XORR(ByVal STRI As String) As String   '校验码的异或处理
Dim I, J, K As Integer
J = Len(STRI)
K = 0
For I = 1 To J
 K = Asc(Mid$(STRI, I, 1)) Xor K
Next I
fcdd$ = Hex$(K)
If Len(fcdd$) = 1 Then
 XORR = "0" & fcdd$
Else
 XORR = fcdd$
End If
End Function

Private Sub Timer3_Timer()
Dim outstring As String

 MSComm1.InBufferCount = 0 'clear off  inbuffer
   outstring = "@" + "00" + "RD" + "0034"
   fcdd$ = XORR(outstring)
   outstring = outstring + fcdd$ + "*" + Chr$(13)
   MSComm1.Output = outstring
   Time_out = tim
   
  '判断通讯错误
   Do
     If tim > (Time_out + 1) Then
       ERROR_COM = True
     Else
       ERROR_COM = False
     End If
       DoEvents
   Loop Until ((MSComm1.InBufferCount >= 11 + 4 * Lengh) Or (ERROR_COM = True))
   
   Instring = MSComm1.Input
   order1 = Mid(Instring, 6, 2)  '结束码
   Call ErrMessage(order1)
     Text3.Text = Mid(Instring, 8, 4) * 0.099695  '取出数据位
End Sub

Private Sub Timer4_Timer()
Dim outstring As String

 MSComm1.InBufferCount = 0 'clear off  inbuffer
   outstring = "@" + "00" + "RD" + "0038"
   fcdd$ = XORR(outstring)
   outstring = outstring + fcdd$ + "*" + Chr$(13)
   MSComm1.Output = outstring
   Time_out = tim
   
  '判断通讯错误
   Do
     If tim > (Time_out + 1) Then
       ERROR_COM = True
     Else
       ERROR_COM = False
     End If
       DoEvents
   Loop Until ((MSComm1.InBufferCount >= 11 + 4 * Lengh) Or (ERROR_COM = True))
   
   Instring = MSComm1.Input
   order1 = Mid(Instring, 6, 2)  '结束码
   Call ErrMessage(order1)
     Text5.Text = Mid(Instring, 8, 4) * 0.099695  '取出数据位
End Sub

Private Sub Timer5_Timer()
Text6.Text = Time
End Sub

有高手吗！帮帮忙啊

tim 是秒的计数啊应该没什么问题啊