OPC客户端的自动化实现

OPC客户端的自动化实现

OPC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))

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

Imports System.Runtime.InteropServices
2

Public Class Form1
3

Dim GlobalOPCServer As OPCAutomation.OPCServerClass
5

Dim WithEvents ConnectedOPCServer As OPCAutomation.OPCServerClass
6

Dim WithEvents ConnectedGroup As OPCAutomation.OPCGroupClass
7

Dim GlobalOPCItems(4) As OPCAutomation.OPCItem
9

Dim GlobalOPCBlockItems(64) As OPCAutomation.OPCItem
10

'枚举OPC服务器列表
13

Private 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

'连接到指定的OPC服务器
31

Private 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

'服务器断开事件通知
57

Private Sub OnServerShutDown(ByVal Reason As String) Handles ConnectedOPCServer.ServerShutDown
58

btnDisconnectServer_Click(Nothing, New EventArgs())
59

End Sub
60

Private 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

End Select
86

End If
88

Next
89

End Sub
90

'断开到指定OPC服务器的连接
93

Private 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(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(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(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()
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()
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(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
273

End Class
274

posted on 2006-10-27 12:22 天马行空（笨笨）阅读(21285) 评论(111) 收藏举报