OPC UA Server Connection

If secure connection is not required, only the OPC UA server URL needs to be specified in the I/O Device address form to establish the connection. But if the user authentication or message encryption is required, the security settings will need to be configured by using the "OPC UA Client Driver" Configurator plugin.

The plugin provides an option to check if the connection can be established after the settings have been configured.

If the connection cannot be established, the specific error will help to identify the cause of the problem.

Points to consider include:

• The user credentials are stored in ArchestraA™ Data Store and the ArchestraA™ Data Store service must be running on the machine for the plug-in to store the data and for the driver to read it. The ArchestraA™ Data Store service should be installed and running after the driver installation.

• When the user credentials are configured for the first time, the plug-in adds the currently logged-in user to the Citect.User.Drivers Windows group so that the I/O Server running under the same user account can read the data. When a user is added to that group for the first time, you will need either to restart the computer or to log in / log out.

• The client and server certificates must be present in the Windows certificate store. The client certificate must have a private key and its "Subject Alternative Name" field should be in the format "urn:HostMachineName:Citect.OPCUA.Client.Driver", where the HostMachineName is the host name of the computer running the driver.

The driver logs can also help to find out why the driver cannot connect to the server.

When full driver logging in enabled by setting the ini parameters ([OPCUA]DebugLevel=ALL and [OPCUA]DebugCategory=ALL), the driver log will contain a number of messages or errors describing the connection attempt for each I/O Device.