OPC UA overview

OPC UA (Open Platform Communications Unified Architecture) is an industrial communication standard developed by the OPC Foundation. It is designed as a platform independent, scalable and a modular service-oriented communication with strong security mechanisms. This makes it an ideal solution for the IoT (Internet of Things) and Industry 4.0. Visit OPC Foundation to learn more.

The OPC UA communication driver is accessed and configured in PcVue using the Application Explorer and the Application Architect. The following are all relevant concepts to the OPC UA driver in PcVue.

Network

In PcVue, OPC UA servers are configured attached to a network. An OPC UA network serves the purpose of defining which station or association of stations manage the connections to the OPC UA servers of the network. It is also at the network level that you configure the certificate PcVue exposes to servers to secure the connection. Refer to the topic How to configure an OPC UA network and server to learn more.

Server

A server is configured attached to a network. It serves the purpose of defining connection parameters to an actual OPC UA server in the system, including the server Uri, the security policy, authentication etc.

Monitoring groups

The built-in OPC UA driver offers two methods to monitor data exposed by OPC UA servers:

• Polling groups - Allow a non-discriminatory, cyclic collection of data

• Subscriptions - Allow a server-triggered, change-oriented collection of data

Refer to the topic How to configure OPC UA Polling groups and Subscriptions to learn more.

Redundant server

 PcVue provides the possibility to connect to redundant OPC UA servers for applications where high availability is of prime importance. Redundant OPC UA servers can prove useful as a backup in case an error occurs with the primary OPC UA server used to open the communication. In PcVue, OPC UA redundant servers are configured in exactly the same way as OPC UA primary servers. Refer to the topic How to configure an OPC UA redundant server to learn more.

Variable mapping

Mapping is the process of linking a variable to its source for value, quality, and timestamp. In PcVue, OPC UA elements can be linked to existing variables in the project or to new variables. This linking process can be carried out from the source tab of the variables configuration dialog or from the OPC UA server mapping dialog. Refer to the topic How to map variables to OPC UA elements and Linking variables to an OPC UA server to learn more.

Security certificates

 PcVue provides the possibility to create security certificates that enable secure exchange of information between OPC UA servers and PcVue. Certificate management is centralized in the Application Explorer, behind the Security node. It offers the possibility to create and manage security certificates. Refer to the topic How to create a security certificate to learn more.

SCADA Basic

 PcVue provides a SCADA Basic instruction for controlling the OPC UA client driver by script. Refer to the topic OPC UA to learn more.

Rules and behavior of cut, copy and paste

The following table describes the rules and behavior, and in particular any restrictions, when using cut or copy and paste on configuration objects in the OPC UA folder.

OPC UA object	Behavior
Network	The pasted Network is given a unique name. Any subordinate servers are duplicated using the original name. The mapping of any variables is not duplicated.
Server	The pasted server is given a unique name. Any subordinate redundant servers are duplicated using the original name.
Polling group	The pasted polling group is given a unique name.
Subscription	The pasted subscription is given a unique name.