This Annex provides details on mapping OPC COM Data Access (DA) information to OPC UA to help vendors migrate to OPC UA based systems while still being able to access information from existing OPC COM DA systems.

The OPC Foundation provides COM UA Wrapper and Proxy samples that act as a bridge between the OPC DA and the OPC UA systems.

The COM UA Wrapper is an OPC UA Server that wraps an OPC DA Server and with that enables an OPC UA Client to access information from the DA Server. The COM UA Proxy enables an OPC DA Client to access information from an OPC UA Server.

The mappings describe generic DA interoperability components. It is recommended that vendors use this mapping if they develop their own components, however, some applications may benefit from vendor specific mappings.