Open Productivity and Connectivity Specification (OPC Specification)

The Open Productivity and Connectivity (OPC) Specification is a set of standards developed by multiple leading automation industry suppliers in 1996 to link process control hardware and Windows software applications. The OPC Foundation oversees the development of OPC Specification standards.

The OPC Specification is now known as the Data Access Specification, OPC Data Access (OPC DA) or OPC Data Access Specification (OPC DA).

The OPC Specification defines a standard set of objects, interfaces and methods for application automation. OPC Data Access - the most common OPC Specification implementation - is used by manufacturing facilities for the following purposes:

• Read and write real-time data from various vendors
• Enable interoperability of automated process and manufacturing applications
• Define uniform methods of accessing manufacturing device field data

OPC Specification design is based on multiple technologies, such as Object Linking and Embedding (OLE), Component Object Model (COM) and Distributed Component Object Model (DCOM) developed by Microsoft for Microsoft operating systems (OS). Initially, COM/DCOM technologies provided a framework for OPC software applications.

The OPC Specification does not restrict server access to process control and automation devices. Because OPC Foundation membership is not a system integrator requirement, OPC servers are under continuous development by OPC Foundation members and non-members.