OPC Server is written for a particular device, it can be reused by any application that is able to act as an OPC client. OPC servers can be linked and communicate to other servers. OPC servers use Microsoft's OLE technology (also known as the Component Object Model, or COM) to communicate with clients. COM technology permits a standard for real-time information exchange between software applications and process hardware to be defined. Some OPC specifications are published, but others are available only to members of the OPC Foundation. So while no company "owns" OPC and anyone can develop an OPC server whether or not they are a member of the OPC Foundation, non-members will not necessarily be using the latest specifications. It is up to each company that requires OPC products to ensure that their products are certified and that their system integrators have the necessary training. See also Modbus RTU Lonworks KNX (standard) IEC 61850 MTConnect References External links FatRat Library - free OPC server developers toolkit OpenOPC - Open Source OPC client development in Python OPC Foundation OPC Programmers' Connection OPC Unified Architecture Address Space e-book prOpc Library - Open Source OPC server/client toolkit in Delphi Application programming interfaces Industrial automation Computer standards