Opc data Access Automation Specification

4.1.5.2

 

Connect 

Description 

Must be called to establish connection to an OPC Data Access Server (that implements the 

custom interface).  

Syntax 

Connect (ProgID As String, Optional Node As Variant) 

Part Description 

ProgID 

The ProgID is a string that uniquely identifies the registered real OPC Data Access 

Server (that implements the custom interface).  

Node 

The Node name can specify another computer to connect using DCOM. 

Remarks 

Each instance of an OPC Automation Server is  “connected” to an OPC Data Access Server 

(which implements the custom interface). 

Node is optional. The use of a node name makes use of DCOM to access another computer. 

Acceptable node names are UNC names (“Server”), or DNS names (“server.com”, 

“www.vendor.com”, or “180.151.19.75”). 

Calling this function will result in the automation wrapper calling CoCreateInstanceEx to create a 

Data Access Custom(specified by the ProgID )server on the specified machine(StrNodeName). 

If this function is called a second time without calling explicitly calling disconnect the 

automation wrapper will automatically disconnect the existing connection. 

See Also 

Use the GetOPCServers method to find the legal ProgIDs.  

Example 

‘ Connect to the first registered OPCServer returned from the GetOPCServers 

Dim AllOPCServers As Variant 

AllOPCServers = AnOPCServer.GetOPCServers 

AnOPCServer.Connect(AllOPCServers(1)) 

 ‘Connect to a specific server on some remote node 

Dim ARealOPCServer As String 

Dim ARealOPCNodeName As String 

ARealOPCServer = “VendorX.DataAccessCustomServer” 

ARealOPCNodeName = “SomeComputerNodeName” 

AnOPCServer.Connect (ARealOPCServer, ARealOPCNodeName) 

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OPC Data Access Automation Specification2.02