OPC客户端的自动化实现

转载：http://www.cnblogs.com/Phoenix-Rock/archive/2007/02/26/541696.html

PC是建立在COM，DCOM的基础商的，因此绝大多数语言都可以很好的进行开发。在Net中开发客户端有以下几种方式：

（1）       使用OPCNetAPI，需要用到OPCNetAPI.dll，OPCNetAPI.Com.dll

（2）       使用自动化接口，需要用到OPCDAAuto.dll

（3）       使用自定义接口，需要用到多个Wrapper：OpcRcw.Ae.dll，OpcRcw.Batch.dll，OpcRcw.Comn.dll，OpcRcw.Da.dll，OpcRcw.Dx.dll，OpcRcw.Hda.dll，OpcRcw.Sec.dll

以上开发方式所需的动态链接库可以从OPC基金会（http://www.opcfoundation.org/）的网站上下载，一些下载项目可能需要注册，或成为基金会的成员。

不同的方式有各自的有缺点，请参见…

本文使用自动化接口，VB.Net语言进行开发，开发项目是无线射频（RFID）卡方面的应用，典型的如公交车，或公司考勤使用的刷卡机。需要注意的是自动化接口存在一个“不是问题”的问题，数组下标是以1开始的，而不是传统计算机开发上的以0开始。不知道设计者头脑是怎么想（有人知道吗？）；这可能会给一些语言的开发造成问题（有人碰到吗，没有你就是幸运的）

需求：OPCDAAuto.dll或该Dll的Interop

(一) ：客户端开发流程

OPC客户端的开发主要遵循下图所示的开发流程，下面就从以下几个开发步骤进行说明
 

(二) ：枚举OPC服务器列表

枚举服务器主要是通过OPCServer接口的GetOPCServers方法来实现的，该方法会返回OPC服务器数组（以1为下界，上面已有说明），以下是代码段

    '枚举OPC服务器列表

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        Try

            GlobalOPCServer = New OPCAutomation.OPCServerClass()

            Dim ServerList As Object = GlobalOPCServer.GetOPCServers

            For index As Short = LBound(ServerList) To UBound(ServerList) '加入控件列表中，注意这里使用LBound和UBound

                cbbServerList.Items.Add(ServerList(index))

            Next

            If cbbServerList.Items.Count > 0 Then

                cbbServerList.SelectedIndex = 0

            End If

            ResetControlStatus() '设置控件状态

            GlobalOPCServer = Nothing

        Catch Ex As Exception

            MessageBox.Show("List OPC servers failed: " + Ex.Message, "OPCSample", MessageBoxButtons.OK)

        End Try

End Sub

(三) ：连接OPC服务器

自动化接口中连接到服务器是使用connect方法

Public Overridable Sub Connect(ByVal ProgID As String, Optional ByVal Node As Object = Nothing)

ProgID指服务器的ProgID，Node代表网络节点，如果是本机则放空即可。

连接到服务器后，以下属性需要特别注意：

OPCServer.StartTime：服务器的启动时间

OPCServer.CurrentTime：服务器的当前时间，各个客户端可以通过这个属性值完成一些同步的操作

OPCGroups.DefaultGroupIsActive：以后添加的Group是否默认激活

OPCGroups.DefaultGroupDeadBand：Group的默认死区，变化量超过死区后将会触发DataChange事件，

合理的设置该值可以提高程序性能

OPCGroups.Count：下属组（Group）的数量

OPCGroups.DefaultGroupLocalID：组（Group）的默认通信区域编号，如1024

OPCGroups.DefaultGroupUpdateRate：组（Group）的默认刷新率，该属性也比较重要

OPCGroups.DefaultGroupTimeBias：组（Group）的默认时间偏差

(四) ：添加组（Group）和项 （Item）

添加组和项需要用到Groups.Add和Items.AddItem方法，以下是原型：

Function Add(Optional ByVal Name As Object = Nothing) As OPCAutomation.OPCGroup

Function AddItem(ByVal ItemID As String, ByVal ClientHandle As Integer) As OPCAutomation.OPCItem

       组也有两个重要的属性

       Group.UpdateRate：刷新率，该属性通Groups的UpdateRate意义一样，如果这个值有设置，则以这个值为准

       Group. IsSubscribed：是否使用订阅功能

     以下是代码段

         '连接到指定的OPC服务器

    Private Sub btnConnectServer_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnConnectServer.Click

        If cbbServerList.Text <> "" Then

            ConnectedOPCServer = New OPCAutomation.OPCServerClass()

            Try

                ConnectedOPCServer.Connect(cbbServerList.Text)

                '设置组集合的默认属性

                ConnectedOPCServer.OPCGroups.DefaultGroupIsActive = True

                ConnectedOPCServer.OPCGroups.DefaultGroupDeadband = 0

                '添加组

                ConnectedGroup = ConnectedOPCServer.OPCGroups.Add()

                ConnectedGroup.UpdateRate = 3 * 1000 '刷新虑，用于下面的DataChange事件

                ConnectedGroup.IsSubscribed = True '使用订阅功能

                '添加项

                GlobalOPCItems(0) = ConnectedGroup.OPCItems.AddItem("Reader_Device.OpenCard", 0)

                GlobalOPCItems(1) = ConnectedGroup.OPCItems.AddItem("Reader_Device.CloseCard", 1)

                GlobalOPCItems(2) = ConnectedGroup.OPCItems.AddItem("Reader_Device.CardNO", 2)

                RefreshServerStatus() '刷新服务器状态

            Catch ex As Exception

                ConnectedOPCServer = Nothing

                MessageBox.Show("OPC server connect failed : " + ex.Message, "OPCSample", MessageBoxButtons.OK)

            End Try

            ResetControlStatus()

        End If

    End Sub

(五) ：读写操作与事件控制

读写操作包括同步和异步两种操作方式，以下是这几个方法的原型：

Group的同步读事件

Sub SyncRead(ByVal Source As Short, ByVal NumItems As Integer, ByRef ServerHandles As System.Array, ByRef Values As System.Array, ByRef Errors As System.Array, Optional ByRef Qualities As Object = Nothing, Optional ByRef TimeStamps As Object = Nothing)

 

Group的同步写事件

Sub SyncWrite(ByVal NumItems As Integer, ByRef ServerHandles As System.Array, ByRef Values As System.Array, ByRef Errors As System.Array)

 

Group的异步读事件

Sub AsyncRead(ByVal NumItems As Integer, ByRef ServerHandles As System.Array, ByRef Errors As System.Array, ByVal TransactionID As Integer, ByRef CancelID As Integer)

 

Group的异步写事件

Sub AsyncWrite(ByVal NumItems As Integer, ByRef ServerHandles As System.Array, ByRef Values As System.Array, ByRef Errors As System.Array, ByVal TransactionID As Integer, ByRef CancelID As Integer)

如果使用异步的读写操作，那么还需要实现Group中的ReadComplete和WriteComplete两个事件

Public Event AsyncReadComplete(ByVal TransactionID As Integer, ByVal NumItems As Integer, ByRef ClientHandles As System.Array, ByRef ItemValues As System.Array, ByRef Qualities As System.Array, ByRef TimeStamps As System.Array, ByRef Errors As System.Array)

 

Public Event AsyncWriteComplete(ByVal TransactionID As Integer, ByVal NumItems As Integer, ByRef ClientHandles As System.Array, ByRef Errors As System.Array)

其他相关的重要事件包括：

Group数据变化时的通知事件

Public Event DataChange(ByVal TransactionID As Integer, ByVal NumItems As Integer, ByRef ClientHandles As System.Array, ByRef ItemValues As System.Array, ByRef Qualities As System.Array, ByRef TimeStamps As System.Array)

 

Group的异步取消事件

Public Event AsyncCancelComplete(ByVal CancelID As Integer)

 

Server（服务器）关闭通知事件

Public Event ServerShutDown(ByVal Reason As String)

 

以下是这些实现的代码段

    '读取卡片指定的块号的值

    Private Sub btnReadCard_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)

        If Not (ConnectedGroup Is Nothing) Then

            Try

                '获取块号

                Dim BlockNo As Short = CByte(ReadBlockNo.Text)

                '如果要获取数据的块所对应的项还没有创建，就创建它

                If GlobalOPCBlockItems(BlockNo) Is Nothing Then

                    GlobalOPCBlockItems(BlockNo) = ConnectedGroup.OPCItems.AddItem("Reader_Device.Block" & CStr(BlockNo), 200 + BlockNo)

                End If

                '准备参数数组

                Dim ServerResults As System.Array

                Dim ServerErrors As System.Array

                Dim ServerHandles(1) As Integer

                ServerHandles(1) = GlobalOPCBlockItems(BlockNo).ServerHandle

                '读取值

                ConnectedGroup.SyncRead(OPCAutomation.OPCDataSource.OPCDevice, 1, ServerHandles, ServerResults, ServerErrors)

                If ServerErrors(1) <> 0 Then

                    MsgBox("Read Card Failed:" & ServerErrors(1))

                Else

                    txtReadBlockNo.Text = ServerResults(1)

                End If

            Catch ex As Exception

                MessageBox.Show("OPC server Read Card failed: " + ex.Message, "OPCSample", MessageBoxButtons.OK)

            End Try

        End If

End Sub

 

    '写卡片指定块的值

    Private Sub btnWriteCard_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)

        If Not (ConnectedGroup Is Nothing) Then

            Try

                '获取块号

                Dim BlockNo As Short = CByte(WriteBlockNo.Text)

                '如果要写入数据的块所对应的项还没有创建，就创建它

                If GlobalOPCBlockItems(BlockNo) Is Nothing Then

                    GlobalOPCBlockItems(BlockNo) = ConnectedGroup.OPCItems.AddItem("Reader_Device.Block" & CStr(BlockNo), 200 + BlockNo)

                End If

                '准备参数数组

                Dim ServerValues(1) As Object

                Dim ServerErrors As Array

                Dim ServerHandles(1) As Integer

                ServerHandles(1) = GlobalOPCBlockItems(BlockNo).ServerHandle

                ServerValues(1) = txtWriteBlockNo.Text

                '写入值

                ConnectedGroup.SyncWrite(1, ServerHandles, ServerValues, ServerErrors)

                If ServerErrors(1) <> 0 Then

                    MsgBox("Write Card Failed:" & ServerErrors(1))

                Else

                    MsgBox("Write Card Succeed")

                End If

            Catch ex As Exception

                MessageBox.Show("OPC server Write Card failed: " + ex.Message, "OPCSample", MessageBoxButtons.OK)

            End Try

        End If

End Sub

(六) ：断开服务器

断开服务器只要使用OPCServer的Disconnect方法几个，以下是代码段：

    '断开到指定OPC服务器的连接

    Private Sub btnDisconnectServer_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisconnectServer.Click

        If Not (ConnectedOPCServer Is Nothing) Then

            Try

                ConnectedOPCServer.Disconnect()

            Catch ex As Exception

                MessageBox.Show("OPC server disconnect failed: " + ex.Message, "OPCSample", MessageBoxButtons.OK)

            Finally

                ConnectedOPCServer = Nothing

                ResetControlStatus()

            End Try

        End If

End Sub

(七) ：相关链接

非常好的一个OPC技术网站http://www.opcconnect.com/

OPC基金会网址http://www.opcfoundation.org/

国内的一个比较好的OPC网站http://www.opc-china.com/Index.html

(八)：全部源码

代码

Imports System.Runtime.InteropServices
  2Public Class Form1Class Form1
   3
   4     Dim GlobalOPCServer As OPCAutomation.OPCServerClass
   5     Dim WithEvents ConnectedOPCServer As OPCAutomation.OPCServerClass
   6     Dim WithEvents ConnectedGroup As OPCAutomation.OPCGroupClass
   7
   8     Dim GlobalOPCItems( 4 ) As OPCAutomation.OPCItem
   9     Dim GlobalOPCBlockItems( 64 ) As OPCAutomation.OPCItem
  10
  11
  12      ' 枚举OPC服务器列表
  13     Private Sub Form1_Load()Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
  14         Try
  15             GlobalOPCServer  =  New OPCAutomation.OPCServerClass()
  16             Dim ServerList As Object  =  GlobalOPCServer.GetOPCServers
  17             For index As Short  =  LBound(ServerList) To UBound(ServerList)  ' 加入控件列表中，注意这里使用LBound和UBound
  18                 cbbServerList.Items.Add(ServerList(index))
  19             Next
  20             If cbbServerList.Items.Count  >   0  Then
  21                 cbbServerList.SelectedIndex  =   0
  22             End If
  23             ResetControlStatus()  ' 设置控件状态
  24             GlobalOPCServer  =  Nothing
  25         Catch Ex As Exception
  26             MessageBox.Show( " List OPC servers failed:  "   +  Ex.Message,  " OPCSample " , MessageBoxButtons.OK)
  27         End Try
  28     End Sub
  29
  30      ' 连接到指定的OPC服务器
  31     Private Sub btnConnectServer_Click()Sub btnConnectServer_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnConnectServer.Click
  32         If cbbServerList.Text  <>   ""  Then
  33             ConnectedOPCServer  =  New OPCAutomation.OPCServerClass()
  34             Try
  35                 ConnectedOPCServer.Connect(cbbServerList.Text)
  36                  ' 设置组集合的默认属性
  37                 ConnectedOPCServer.OPCGroups.DefaultGroupIsActive  =  True
  38                 ConnectedOPCServer.OPCGroups.DefaultGroupDeadband  =   0
  39                  ' 添加组
  40                 ConnectedGroup  =  ConnectedOPCServer.OPCGroups.Add()
  41                 ConnectedGroup.UpdateRate  =   3   *   1000   ' 刷新虑，用于下面的DataChange事件
  42                 ConnectedGroup.IsSubscribed  =  True  ' 使用订阅功能
  43                  ' 添加项
  44                 GlobalOPCItems( 0 )  =  ConnectedGroup.OPCItems.AddItem( " Reader_Device.OpenCard " ,  0 )
  45                 GlobalOPCItems( 1 )  =  ConnectedGroup.OPCItems.AddItem( " Reader_Device.CloseCard " ,  1 )
  46                 GlobalOPCItems( 2 )  =  ConnectedGroup.OPCItems.AddItem( " Reader_Device.CardNO " ,  2 )
  47                 RefreshServerStatus()  ' 刷新服务器状态
  48             Catch ex As Exception
  49                 ConnectedOPCServer  =  Nothing
  50                 MessageBox.Show( " OPC server connect failed :  "   +  ex.Message,  " OPCSample " , MessageBoxButtons.OK)
  51             End Try
  52             ResetControlStatus()
  53         End If
  54     End Sub
  55
  56      ' 服务器断开事件通知
  57     Private Sub OnServerShutDown()Sub OnServerShutDown(ByVal Reason As String) Handles ConnectedOPCServer.ServerShutDown
  58         btnDisconnectServer_Click(Nothing, New EventArgs())
  59     End Sub
  60
  61     Private Sub OnGroupDataChange()Sub OnGroupDataChange(ByVal TransactionID As Integer, ByVal NumItems As Integer, ByRef ClientHandles As System.Array, ByRef ItemValues As System.Array, ByRef Qualities As System.Array, ByRef TimeStamps As System.Array) Handles ConnectedGroup.DataChange
  62         For i As Integer  =   1  To NumItems
  63             If Qualities(i)  =  OPCAutomation.OPCQuality.OPCQualityGood Then
  64                 Select Case ClientHandles(i)
  65                     Case  2
  66                         txtCardNo.Text  =  CStr(ItemValues(i))
  67                     Case  200   ' 测试7张卡片
  68                         txtValueBlock0.Text  =  CStr(ItemValues(i))
  69                     Case  201
  70                         txtValueBlock1.Text  =  CStr(ItemValues(i))
  71                     Case  202
  72                         txtValueBlock2.Text  =  CStr(ItemValues(i))
  73                     Case  203
  74                         txtValueBlock3.Text  =  CStr(ItemValues(i))
  75                     Case  204
  76                         txtValueBlock4.Text  =  CStr(ItemValues(i))
  77                     Case  205
  78                         txtValueBlock5.Text  =  CStr(ItemValues(i))
  79                     Case  206
  80                         txtValueBlock6.Text  =  CStr(ItemValues(i))
  81                     Case  207
  82                         txtValueBlock7.Text  =  CStr(ItemValues(i))
  83                     Case Else
  84
  85                 End Select
  86
  87             End If
  88         Next
  89     End Sub
  90
  91
  92      ' 断开到指定OPC服务器的连接
  93     Private Sub btnDisconnectServer_Click()Sub btnDisconnectServer_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisconnectServer.Click
  94         If Not (ConnectedOPCServer Is Nothing) Then
  95             Try
  96                 ConnectedOPCServer.Disconnect()
  97             Catch ex As Exception
  98                 MessageBox.Show( " OPC server disconnect failed:  "   +  ex.Message,  " OPCSample " , MessageBoxButtons.OK)
  99             Finally
100                 ConnectedOPCServer  =  Nothing
101                 ResetControlStatus()
102             End Try
103         End If
104     End Sub
105
106      ' 开卡，并返回卡号
107     Private Sub btnOpenCard_Click()Sub btnOpenCard_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
108         If ConnectedGroup IsNot Nothing Then
109             Try
110                  ' 准备参数数组
111                 Dim ServerHandles( 1 ) As Integer
112                 Dim ServerValues( 1 ) As Object
113                 Dim ServerErrors As System.Array
114                 ServerHandles( 1 )  =  GlobalOPCItems( 0 ).ServerHandle
115                 ServerValues( 1 )  =   1
116                  ' 写入值，用于执行OpenCard的操作
117                 ConnectedGroup.SyncWrite( 1 , ServerHandles, ServerValues, ServerErrors)
118                 If ServerErrors( 1 )  <>   0  Then
119                     MsgBox( " OpenCardError:  "   &  ServerErrors( 1 ))
120                 End If
121
122                 ServerHandles( 1 )  =  GlobalOPCItems( 2 ).ServerHandle
123                 Dim ServerResult As System.Array
124                  ' 读取卡号
125                 ConnectedGroup.SyncRead(OPCAutomation.OPCDataSource.OPCDevice,  1 , ServerHandles, ServerResult, ServerErrors)
126                 If ServerErrors( 1 )  <>   0  Then
127                     MsgBox( " ReadCardNoError:  "   &  ServerErrors( 1 ))
128                 Else
129                     txtCardNo.Text  =  ServerResult( 1 )
130                 End If
131             Catch ex As Exception
132                 MessageBox.Show( " OPC server Open Card failed:  "   +  ex.Message,  " OPCSample " , MessageBoxButtons.OK)
133             End Try
134             ResetControlStatus()
135         End If
136     End Sub
137
138      ' 读取卡片指定的块号的值
139     Private Sub btnReadCard_Click()Sub btnReadCard_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
140         If Not (ConnectedGroup Is Nothing) Then
141             Try
142                  ' 获取块号
143                 Dim BlockNo As Short  =  CByte(ReadBlockNo.Text)
144                  ' 如果要获取数据的块所对应的项还没有创建，就创建它
145                 If GlobalOPCBlockItems(BlockNo) Is Nothing Then
146                     GlobalOPCBlockItems(BlockNo)  =  ConnectedGroup.OPCItems.AddItem( " Reader_Device.Block "   &  CStr(BlockNo),  200   +  BlockNo)
147                 End If
148                  ' 准备参数数组
149                 Dim ServerResults As System.Array
150                 Dim ServerErrors As System.Array
151                 Dim ServerHandles( 1 ) As Integer
152                 ServerHandles( 1 )  =  GlobalOPCBlockItems(BlockNo).ServerHandle
153                  ' 读取值
154                 ConnectedGroup.SyncRead(OPCAutomation.OPCDataSource.OPCDevice,  1 , ServerHandles, ServerResults, ServerErrors)
155                 If ServerErrors( 1 )  <>   0  Then
156                     MsgBox( " Read Card Failed: "   &  ServerErrors( 1 ))
157                 Else
158                     txtReadBlockNo.Text  =  ServerResults( 1 )
159                 End If
160             Catch ex As Exception
161                 MessageBox.Show( " OPC server Read Card failed:  "   +  ex.Message,  " OPCSample " , MessageBoxButtons.OK)
162             End Try
163         End If
164     End Sub
165
166      ' 写卡片指定块的值
167     Private Sub btnWriteCard_Click()Sub btnWriteCard_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
168         If Not (ConnectedGroup Is Nothing) Then
169             Try
170                  ' 获取块号
171                 Dim BlockNo As Short  =  CByte(WriteBlockNo.Text)
172                  ' 如果要写入数据的块所对应的项还没有创建，就创建它
173                 If GlobalOPCBlockItems(BlockNo) Is Nothing Then
174                     GlobalOPCBlockItems(BlockNo)  =  ConnectedGroup.OPCItems.AddItem( " Reader_Device.Block "   &  CStr(BlockNo),  200   +  BlockNo)
175                 End If
176                  ' 准备参数数组
177                 Dim ServerValues( 1 ) As Object
178                 Dim ServerErrors As Array
179                 Dim ServerHandles( 1 ) As Integer
180                 ServerHandles( 1 )  =  GlobalOPCBlockItems(BlockNo).ServerHandle
181                 ServerValues( 1 )  =  txtWriteBlockNo.Text
182                  ' 写入值
183                 ConnectedGroup.SyncWrite( 1 , ServerHandles, ServerValues, ServerErrors)
184                 If ServerErrors( 1 )  <>   0  Then
185                     MsgBox( " Write Card Failed: "   &  ServerErrors( 1 ))
186                 Else
187                     MsgBox( " Write Card Succeed " )
188                 End If
189             Catch ex As Exception
190                 MessageBox.Show( " OPC server Write Card failed:  "   +  ex.Message,  " OPCSample " , MessageBoxButtons.OK)
191             End Try
192         End If
193     End Sub
194
195      ' 重设控件状态
196     Private Sub ResetControlStatus()Sub ResetControlStatus()
197         If ConnectedOPCServer Is Nothing Then
198             btnConnectServer.Enabled  =  True
199             btnDisconnectServer.Enabled  =  False
200             btnReadCard.Enabled  =  False
201             btnWriteCard.Enabled  =  False
202             btnOpenCard.Enabled  =  False
203             btnCloseCard.Enabled  =  False
204             ReadBlockNo.Value  =   0
205             WriteBlockNo.Value  =   0
206             txtReadBlockNo.Text  =   ""
207             txtWriteBlockNo.Text  =   " 00000000000000000000000000000000 "
208             txtCardNo.Text  =   ""
209
210             txtSrvStartTime.Text  =   ""
211             txtSrvCurrTime.Text  =   ""
212             txtSrvGroupCount.Text  =   ""
213             txtSrvGroupDeadBand.Text  =   ""
214             txtSrvGroupDefActive.Text  =   ""
215             txtSrvGroupLocalID.Text  =   ""
216             txtSrvGroupTimeBias.Text  =   ""
217             txtSrvRequestRate.Text  =   ""
218         Else
219             btnConnectServer.Enabled  =  False
220             btnDisconnectServer.Enabled  =  True
221             If txtCardNo.Text  =   ""  Then
222                 btnReadCard.Enabled  =  False
223                 btnWriteCard.Enabled  =  False
224                 btnOpenCard.Enabled  =  True
225                 btnCloseCard.Enabled  =  False
226             Else
227                 btnReadCard.Enabled  =  True
228                 btnWriteCard.Enabled  =  True
229                 btnOpenCard.Enabled  =  True
230                 btnCloseCard.Enabled  =  True
231             End If
232         End If
233     End Sub
234
235      ' 刷新服务器状态属性信息
236     Private Sub RefreshServerStatus()Sub RefreshServerStatus()
237         If ConnectedOPCServer IsNot Nothing Then
238             txtSrvStartTime.Text  =  ConnectedOPCServer.StartTime.ToString()
239             txtSrvCurrTime.Text  =  ConnectedOPCServer.CurrentTime.ToString()
240             With ConnectedOPCServer.OPCGroups
241                 txtSrvGroupCount.Text  =  CStr(.Count)
242                 txtSrvGroupDeadBand.Text  =  CStr(.DefaultGroupDeadband)
243                 If .DefaultGroupIsActive Then
244                     txtSrvGroupDefActive.Text  =   " True "
245                 Else
246                     txtSrvGroupDefActive.Text  =   " False "
247                 End If
248                 txtSrvGroupLocalID.Text  =  CStr(.DefaultGroupLocaleID)
249                 txtSrvGroupTimeBias.Text  =  CStr(.DefaultGroupTimeBias)
250                 txtSrvRequestRate.Text  =  CStr(.DefaultGroupUpdateRate)
251             End With
252         End If
253     End Sub
254
255      ' 关闭卡片
256     Private Sub btnCloseCard_Click()Sub btnCloseCard_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
257         If ConnectedGroup IsNot Nothing Then
258             Try
259                 Dim ServerHandles( 1 ) As Integer
260                 Dim ServerValues( 1 ) As Object
261                 Dim ServerErrors As System.Array
262                 ServerHandles( 1 )  =  GlobalOPCItems( 1 ).ServerHandle
263                 ServerValues( 1 )  =   1
264                 ConnectedGroup.SyncWrite( 1 , ServerHandles, ServerValues, ServerErrors)
265                 If ServerErrors( 1 )  <>   0  Then
266                     MsgBox( " Close Card Error:  "   &  ServerErrors( 1 ))
267                 End If
268             Catch ex As Exception
269                 MessageBox.Show( " OPC server Close Card failed:  "   +  ex.Message,  " OPCSample " , MessageBoxButtons.OK)
270             End Try
271         End If
272     End Sub
273End Class