What technology does OPC utilize for its process control standard?

OPC, which stands for OLE for Process Control, primarily utilizes Microsoft DCOM (Distributed Component Object Model) for its process control standard. DCOM is a foundational technology that allows software components to communicate over a network. It is specifically designed to enable interoperability and facilitate communication between software applications, particularly in industrial automation environments.

The use of DCOM within OPC is crucial because it enables real-time data exchange between different devices and systems, which is essential in process control applications. By leveraging DCOM, OPC can transmit data efficiently and manage interactions among multiple software systems that may be distributed across various locations.

In contrast, the other technologies listed, such as Java RMI, REST APIs, and SOAP Web Services, are not integral to the original OPC standard. While Java RMI facilitates remote method invocation for Java applications and REST/ SOAP are modern web service architectures used for web communication, they do not play a role in the OPC standard established predominantly around Microsoft's DCOM technology. Thus, DCOM remains the correct choice as it underpins the operational capabilities of OPC in industrial control settings.