OPC-simple software integration for legacy systems

This paper discusses the use of OLE for process control as a medium for connection of third-party applications to legacy control systems. This topic is becoming more important as legacy system users attempt to "open up" their systems to third-party applications. Several approaches to implementing the OLE for process control interface to existing systems are discussed, including emulation of field hardware, use of available communication ports, and legacy application nodes. The advantages and disadvantages of implementing each approach are discussed, including feasibility, performance and cost. A brief overview of the client-server paradigm is provided, as this is the cornerstone of OLE for process control communications. Finally, some examples of successful connections to legacy systems are presented.