OPC UA Clients

The OPC Unified Architecture client architecture models the Client endpoint of client/server interactions. Figure 1 illustrates the major elements of a typical OPC Unified Architecture client and how they relate to each other.

Figure 1: OPC UA Client Architecture

The client application - a software package - is the code that implements the client functionality. It uses the OPC Unified Architecture client API to send and receive OPC Unified Architecture service requests and responses to the OPC Unified Architecture server.

Note that the “OPC UA Client API” is an internal interface that isolates the client application code from an OPC Unified Architecture communication stack. The OPC Unified Architecture communication stack converts OPC Unified Architecture client API calls into messages and sends them through the underlying communications entity to the server at the request of the client application. The OPC Unified Architecture communication stack also receives response and notification messages from the underlying communications entity and delivers them to the client application through the OPC Unified Architecture client API.