OPC is open connectivity via open standards. They fill a need in automation like printer drivers did for Windows. See the summary of current and emerging OPC Specifications and OPC Certification.
OPC Tagline has been Dedicated to Interoperability in Automation & Beyond; and we have went through various permutations of associating letters to the 3 letter acronym inclusive of ......
The OPC Foundation - The Interoperability Standard for Industrial Automation & Other Related Domains
Here s a great picture of the OPC Architecture.
OPC is all about Open Productivity & Connectivity in industrial automation and the enterprise systems that support industry. Interoperability is assured through the creation and maintenance of open standards specifications. There are currently seven standards specifications completed or in development.
Based on fundamental standards and technology of the general computing market, the OPC Foundation adapts and creates specifications that fill industry-specific needs. OPC will continue to create new standards as needs arise and to adapt existing standards to utilize new technology.