Hardware Requirements

In the OPC architecture, each variety of server is allocated a unique identifier, known as a Class ID. OPC clients use these 128-bit numbers, frequently displayed in the form 6B29FC40-CA47-1067-B31D-00DD010662DA, to access the particular vendor's OPC server. To make it easier for users, these numbers are often referred to by a more manageable string identifier called a ProgID (Program Identifier). These identifiers usually take the form Vendor.Application with an optional version number appended; for example, the Plant SCADA OPC Server ProgID is Plant SCADA.OPC.

Before the OPC client driver can access a particular OPC server, the server’s ProgID needs to be entered into the Plant SCADA I/O server registry. Where an in-process server or a local server is being used, this should have been done automatically when the server was installed. To access a remote server, refer to the documentation accompanying the server. Frequently, this step is achieved using a registry script (a .REG file) or a small executable.

Note:
• Familiarize yourself with the target OPC server(s) before using this driver. This will help you enter the item identifiers for the tag addresses using the correct syntax.
• Using remote servers requires configuring DCOM security. Since configuring security can be complex, you should plan your system settings in advance, and establish a protocol so that the Windows accounts to be used by operators have sufficient privilege. If sufficient privileges are not established, communications errors may result. See Software Requirements for more information.