翻譯|使用教程|編輯:王香|2019-04-15 10:57:20.000|閱讀 969 次
概述:此示例的代碼使用OPC 如果從.NET訪問OPC Server,則需要交換COM和.NET的包裝器。 自動化包裝器(OPCDAAUTO.DLL),因此它幾乎等于VB6.0。
# 界面/圖表報表/文檔/IDE等千款熱門軟控件火熱銷售中 >>
OPC Server是一套利用微軟的COM/DCOM技術實現工業自動化資料獲取的架構。OPC Server提供OPC接口,它將與之相連的物理設備(PLC)的信息值通過接口返回到客戶端應用程序。也就是說,客戶端通過這些接口,可以獲得與OPC Server連接的物理設備的信息。對于集成應用程序,只要支持OPC接口,就能輕易訪問物理設備,而無需相關的技術信息。 程序設計者可以使用相同的程序代碼,操作不同的硬件裝置,充分達成軟件復用的目的。
它使用OPC Server引入了簡單的示例程序。此示例的代碼使用OPC 如果從.NET訪問OPC Server,則需要交換COM和.NET的包裝器。 自動化包裝器(OPCDAAUTO.DLL),因此它幾乎等于VB6.0。

Option Explicit Public OpcServer As IOPCServerDisp Public OpcItemMgt As IOPCItemMgtDisp Public OpcItem As IOPCItemDisp Private Const ItemMax = 8 Private Const OPC_DS_CACHE = 1 Private Const OPC_DS_DEVICE = 2 Dim ClientHandles(ItemMax) As Long Dim ServerHandles As Variant Dim bConnect As Boolean
連接到OPC服務器,創建OPCGroup和添加標簽
Private Sub CONNECT_Click()
  On Error GoTo err_hd
  Dim i%
  If bConnect Then
    CONNECT.Caption = "Connect"
    Set OpcServer = Nothing
    Set OpcItemMgt = Nothing
    Set OpcItem = Nothing
    bConnect = False
    READ_Button.Enabled = False
    WRITE_Button.Enabled = False
    For i% = ItemName.lbound To ItemName.ubound
      ItemName(i%).Enabled = True
    Next i%
    Exit Sub
  End If
  '*** Connect to OPC Server ***
  Set OpcServer = CreateObject(Form1.ServerName.Text)
  If TypeName(OpcServer) = TypeName(Nothing) Then Return
  '*** Add OPCGroup ***
  Dim UpdateRate As Long
  Dim ServerHdl As Long
  UpdateRate = UpdateRateSet.Text
  Set OpcItemMgt = OpcServer.AddGroup("Group One", True, UpdateRate, 22, 1, 0, ServerHdl, UpdateRate)
  If TypeName(OpcItemMgt) = TypeName(Nothing) Then Return
  '*** Add OPCItems ***
  Dim ItemIDs(ItemMax) As String
  Dim AccessPaths(ItemMax) As String
  Dim Active(ItemMax) As Boolean
  Dim Errors As Variant
  Dim ItemObjects As Variant
  Dim DataType(ItemMax) As Variant
  For i% = 0 To ItemMax - 1
    Active(i%) = True
    ClientHandles(i%) = 22 + i%
    AccessPaths(i%) = ""
    ItemIDs(i%) = Form1.ItemName(i%).Text
    DataType(i%) = 2
  Next i%
  OpcItemMgt.AddItems ItemMax, ItemIDs, Active,ClientHandles,
            ServerHandles, Errors, ItemObjects, AccessPaths, DataType
  Set OpcItem = ItemObjects(0)
  bConnect = True
  CONNECT.Caption = "DisConnect"
  READ_Button.Enabled = True
  WRITE_Button.Enabled = True
  For i% = ItemName.lbound To ItemName.ubound
    ItemName(i%).Enabled = False
  Next i%
  Exit Sub
err_hd:
  MsgBox "Error connecting"
  For i% = 0 To ItemMax - 1
    Form1.Value(i%) = "Error"
  Next i%
End Sub
緩存讀取
Private Sub READ_Button_Click()
  Dim ReadValue As Variant
  Dim pQuality As Variant
  Dim pTimestamp As Variant
  Dim Errors As Variant
  Dim i%
  Dim io As IOPCSyncIODisp
  Set io = OpcItemMgt
  '*** Cache Read ***
  io.OPCRead OPC_DS_CACHE, ItemMax, ServerHandles, ReadValue, pQuality, pTimestamp, Errors
  For i% = 0 To ItemMax - 1
    Form1.Value(i%) = ReadValue(i%)
    pTimestamp(i%) = DateAdd("h", 9, pTimestamp(i%))
    Form1.Time(i%) = pTimestamp(i%)
    Form1.Quality(i%) = pQuality(i%)
  Next i%
End Sub
SyncWrite
Private Sub WRITE_Button_Click()
  Dim WriteValue(ItemMax) As Variant
  Dim io As IOPCSyncIODisp
  Dim Errors As Variant
  Dim i%
  Set io = OpcItemMgt
  For i% = 0 To ItemMax - 1
    WriteValue(i%) = Form1.Value(i%)
  Next i%
  '*** SyncWrite ***
  io.OPCWrite ItemMax, ServerHandles, WriteValue, Errors
End Sub
本站文章除注明轉載外,均為本站原創或翻譯。歡迎任何形式的轉載,但請務必注明出處、不得修改原文相關鏈接,如果存在內容上的異議請郵件反饋至chenjj@ke049m.cn