The OPC UA standard is a platform-independent architecture that was created due to the need for compatibility and scalability in various projects and applications. OPC UA, unlike OPC, is not based on Microsoft’s OLE and DCOM technology and is thus extensible to other platforms such as OS X, Linux (JAVA) and Android.
OPC UA is a secure and reliable standard that specifies communications between devices (M2M) and between the machines and the IT and OT system. It is based on the concept of client-server, where the server is an application that provides its data to other applications, and the client is an application that requires or obtains data. In practice, developers strive to make applications that are clients and servers at the same time.