OPC (Object Linking and Embedding (OLE) for Process Control) is having a major impact on automation systems today. The OPC Foundation, chartered with developing the standard, consists of more than 150 companies committed to developing a mechanism that allows different software pieces to communicate with one another. OPC establishes an open industry standard for plug-and-play interoperability between disparate automation devices, systems, and software.
Built on Microsoft ActiveX, OLE Automation, and distributed component object model technology (DCOM), OPC servers and clients exchange real-time information between a variety of systems including distributed control systems (DCS), programmable logic controllers (PLCs), distributed I/O systems, and smart field networks. This results in OPC removing barriers between traditionally proprietary manufacturing systems, easing integration of corporate-wide automation and business systems.
Via the OPC interfaces, information is brought from the robotics system to automation software for monitoring, supervisory control, and statistical-process control. The raw data or filtered results are then sent to the enterprise business systems to record manufacturing data for quality improvements and ISO-9000 compliance.
Before OPC, software vendors spent enormous efforts to develop protocol drivers in order to communicate with the vast array of hardware options available. This not only resulted in software companies often duplicating one another's work, but customers had to be concerned about whether their preferred automation-software package could communicate with their preferred type of hardware (see figure). With the advent of OPC, automation software packages having OPC client capabilities can communicate with any OPC server software through a standard interface. The result: customers can select both preferred software and hardware with confidence that the two will communicate.