Prepare the OPC System

This section of the help explains how to prepare your Allen Bradley devices to communicate with Plant SCADA through OPC.

Software Requirements

In the OPC architecture, each 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 OPC server of a particular vendor. These numbers are often referred by a manageable string identifier called a Program Identifier (ProgID). These identifiers usually take the format Vendor.Application with an optional version number appended. For example, the Allen Bradley FactoryTalk OPC server ProgID is RSOPC Gateway.

Before the OPCLX client driver can access a particular OPC server, the ProgID of the server needs to be entered into the Plant SCADA I/O server registry. If an in-process server or a local server is used, this is done automatically during the installation of the server. 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 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 is complex, you can 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, there may be communication interruptions found.