参考网上vb做客户端通过opc访问wincc自己做的小程序，供初学者参考
同步读写2组，异步读写1组
'模块内定义（放在窗口内定义也可）
Option Explicit
Option Base 1
Public MyOPCGroupColl As OPCGroups 'opc组1定义
Public MyOPCItemColl As OPCItems
Public MyOPCItems As OPCItems
Public MyOPCItem As OPCItem
Public ClientHandles(255) As Long 'q
Public ServerHandles() As Long
Public Errors() As Long
Public pErrors() As Long
Public Server As OPCServer
Public ItemIDs(255) As String 'q
Public GroupName As String
Public NodeName As String
Public itemv(255) As Variant 'q

Public MyOPCGroupColl1 As OPCGroups 'opc组2定义
Public MyOPCItemColl1 As OPCItems
Public MyOPCItems1 As OPCItems
Public MyOPCItem1 As OPCItem
Public ClientHandles1(255) As Long 'q
Public ServerHandles1() As Long
Public Errors1() As Long
Public pErrors1() As Long

Public ItemIDs1(255) As String 'q
Public GroupName1 As String
Public itemv1(255) As Variant 'q

Public ii As Integer
Public tagnum As Integer
Public strColumn As String '--
Public Qualities1
Public TimeStamps1

'窗口内定义
Option Explicit
Option Base 1
Const ServerName = "OPCServer.WinCC"
Public WithEvents MyOPCServer As OPCServer
Public WithEvents MyOPCGroup As OPCGroup
Public WithEvents MyOPCGroup1 As OPCGroup
Public browser As OPCBrowser
Public lastServer As String
Const ncountx = 5 '变量组1变量个数
Const ncountx1 = 5 '变量组2变量个数
Dim plavdu() As Variant 'wincc读取到变量值存放数组1
Dim plavdu1() As Variant 'wincc读取到变量值存放数组2

Dim plaVxie(5) As Variant '写入wincc变量值存放数组1
Dim plaVxie1(5) As Variant '写入wincc变量值存放数组2