Open Platform Communications (OPC): Understanding OPC Server Technology
Kepware has years of experience developing reliable, easy-to-use OPC technologies. Learn about the evolution of OPC standards—from the OPC Foundation launch to the adoption of OPC UA today.
What is open platform communications (OPC)?
OPC is open connectivity in industrial automation. Interoperability is supported by non-proprietary open standards specifications. The first OPC standard specification resulted from the collaboration of leading worldwide automation suppliers and Microsoft. Originally based on Microsoft's OLE COM and DCOM technologies, the specification defined a standard set of objects, interfaces, and methods for use in process control and manufacturing automation software applications to facilitate interoperability. Today, there are hundreds of OPC Data Access servers and clients.
What is an OPC server and how does it work?
Wondering if OPC is a client/server technology? It is. One application acts as the server providing data, and the other as a client using data. OPC is an industrial communication standard that enables data exchange between multi-vendor devices and control applications without proprietary restrictions.
What are the benefits of OPC adoption?
OPC adoption offers several key benefits including interoperability, open solutions, and freedom of choice. Automation suppliers can provide solutions that are truly open, which in turn gives users more choices in automation applications. This is an exciting time in the industry—with OPC adoption, automation professionals around the globe are realizing the advantages of incorporating OPC into their industrial applications.
History of OPC
In 1994, experts from a spectrum of industrial disciplines formed the OPC Foundation. The Foundation's goal was developing a single client/server specification that allows vendors to develop applications that share data in a fast, robust fashion, and eliminate proprietary schemes that forced vendors to duplicate development efforts. The OPC Foundation released the first specification, Data Access Specification 1.0a, in 1996. Using this specification, vendors quickly developed client/server software.
The Data Access specification eliminated the need for application vendors to develop proprietary communications drivers—an effort that often outweighed application development. OPC technology focuses vendor efforts almost exclusively on the client application. The Data Access specification defines how both the client and the server application interface are constructed. If the specification is followed properly, a client vendor knows any OPC server for an industrial device can provide the connectivity needed for data access. Issues like time to market or reliability no longer restrict OPC applications.
Historically, end users needed to select solutions based on communication driver availability or vendor willingness to develop them. OPC gives end users the ability to select best-of-breed software to solve application problems. The user can choose from a variety of OPC server vendors to address a new driver requirement or remedy performance issues. Application vendors can focus on continuously improving core products without the disruption of addressing communication issues and needs.
OPC Unified Architecture (OPC UA)
OPC Unified Architecture (UA) is a platform independent architecture that incorporates all the components of the OPC Classic specifications into one framework. This style of service-oriented architecture (SOA) integrates distributed software components and ensures interoperability and communications. A multi-layer approach to OPC architecture offers platform independence, security, the ability to add new features, information modeling, and functional equivalence.
OPC interoperability resources
Visit the OPC Foundation
To learn more about the OPC standard, visit the OPC Foundation today.
Key OPC UA security concepts
Read our blog to find out how OPC UA protects the security and integrity of your organization’s data.