OPC UA¶

Introduction

Thanks to compliance with the OPC UA (OPC Unified Architecture) standard, with UNIQO it is possible to create applications that communicate with any OPC UA client/server. Also, devices equipped with suitably configured Q Application can operate as either client or server.

Q Studio allows nodes to be imported from an OPC UA server at runtime or at design time to create the desired application logic, similar to what is possible with the PLC tag importer (see Import tags from the PLCs).

To create these functions, the two OPC UA Server and OPC UA Client objects are available.

Server OPC UA

The OPC UA Server object publishes the project information model nodes at runtime. By default it publishes all project nodes, but it is possible to select which nodes to publish and to which users. This object is necessary to allow an OPC UA client to read/write from/to the server, to invoke methods or to listen to events.

It is possible to configure one OPC UA Server object at most in a project.

Client OPC UA

The OPC UA Client object allows communication with an OPC UA server. Specifically, it can access nodes published by the server to read/write, invoke methods, or listen to events.

It is possible to specify the nodes of interest to the server, which can be imported at design time or at runtime. An OPC UA Client can, for example, read some specific object variables, or listen to events generated by alarms and possibly acknowledge all the active alarms, or import the users configured on the server.

It is possible to configure an unlimited number of OPC UA Client* objects in a project.