OPC

OPC is not itself a communication protocol, but functions as a driver—a non-proprietary set of standard interfaces, based on Microsoft’s OLE/COM technology. This standard makes possible interoperability between automation/control applications, field systems/devices, and business/office applications.

Avoiding the traditional requirement of software application developers to write custom drivers to exchange data with field devices, OPC defines a common, high-performance interface that permits this work to be done once, and then easily reused by HMI, SCADA, control and custom applications.

Over a network, OPC uses DCOM (Distributed COM) for remote communications.