From an outside point of view. The machine data can be accessed through the services that should be defined initially as a completely secured term for IT security. OPC UA does not only offer the IT mechanisms that are usual for authentication, signing, and access encryption.
Some important ways of defining the data and services are-
Transport, security, access rights
The layer for actual transport can be extended by additional protocols at any time in the future. The physical transport medium gets its freedom and the protocol transports is a decisive advantage of OPC UA as compare to pure IoT data protocols. Device and manufacturer only need to provide data and services securely.
Data and services are offered by machines in a machine-readable form and if machines and services can talk to each other with simple human engineering than it is possible. The interfaces can be defined by the semantic and can be modeled by relevant professional associations using OPC UA, Harting and Siemens are an example that has been utilized for pushing this into the AutoID industry and the specification for the interface can be realized via the implementation in a short time.
OPC UA that has been integrated with RFID readers can support the AutoID companion spec which is available from stock. In a PLC controller, OPC UA clients are available as PLC open blocks or that can be visualized or can be implemented from the cloud for identical access to devices from both manufacturers with extremely simple engineering.