This chapter describes typical system architectures where this specification can be applied. Figure 29 shows a possible configuration where OPC UA based interfaces are involved.

Figure 29 – System Architecture

Embedded OPC UA servers are directly integrated into a Controller providing Ctrl Program and Ctrl Function Block Objects. Such a server allows direct access to information from a Controller using the OPC UA protocol on the wire. Other embedded applications like HMI acting as OPC UA clients can access the information from Controllers directly without the need of a PC.

OPC UA servers running on a PC platform are capable of providing access to multiple Controllers. They are providing full type information for Ctrl Resource, Ctrl Program and Ctrl Function Block Objects. The communication to the Controllers may use OPC UA or a proprietary protocol on the wire.

In addition to PC based OPC UA servers, this type of server includes access to the engineering system for the Controllers allowing access to the configuration for the use cases Engineering and Service.