YASKAWA MP3000 Series - Page 353

2.12 Communications with a Windows PC (Visual Basic Application)
Using Automatic Reception with the MP3000 as a Slave
2-335
Ethernet Communications
'---- Receive response data ----
Srbuf = Space(4096)
from_len = Len(PC_addr)
rlen = recvfrom(sock, Srbuf, 4096, 0, PC_addr, from_len)
If (rlen <= 0) Then
MsgBox("receive error " & WSAGetLastError())
closesocket(0)
WSACleanup() ’Release the Winsock.DLL
Return -1
End If
'---- Check response data ----
rc = ChkRspData(rlen, Srbuf)
If (rc <> 0) Then
MsgBox("receive data format error")
closesocket(0)
WSACleanup() ’Release the Winsock.DLL
Return -1
End If
Return rc
End Function
'------------------------------------------------------------------------------
’Create Extended MEMOBUS protocol command
'------------------------------------------------------------------------------
Function MkCmdData(ByVal SFC As Byte, ByVal CPUNum As Byte, _
ByVal Adr As Short, ByVal DataNum As Short, _
ByRef Ssbuf As String) As Object
Dim i As Integer
Dim Swork As String
'---- Calculate number of data items ----
'---- MEMOBUS data length from MFC to end of data ----
Select Case SFC
Case &H9
MDATAi = 8
Case Else
MsgBox (“Function code error”)
Return -1
End Select
'---- Calculate total number of data items ----
DATAi = MDATAi + 14 ’218 header (12 bytes) + Length part (2 bytes) + MEMOBUS data length
(variable)
If DATAi > 4096 Then
MsgBox (“Register size error”)
Return -1
End If