OPC Unified Architecture (OPC UA) is the latest specification of Object Linking and Embedding for Process Control (OPC) OPC Foundation and differs significantly from its predecessors.

The goal of the Foundation for this project was to provide a step forward compared to the original model of OPC communication (ie, COM / DCOM ) for a cross-platform service-oriented architecture (SOA) for process control , improved safety and to provide an information model .

OPC UA supports two protocols:

1. The opc.tcp://server binary protocol
2. the protocol for web services http://server

The binary protocol provides the best performance, it takes minimal resources (without XML Parser, SOAP, and HTTP requests, which is important for embedded devices), provides the best interoperability and uses a single TCP port for communication.

The Web Service (SOAP) is better supported by tools or programming environments such as Java or .Net, and is firewall-friendly, using standard HTTP/HTTPS ports