OPC UA Client Device Plugin

The entire OPC UA Client Device Plugin configuration is located under the Node path /System/Devices/OPC UA Client Device. Using this root Node of the device plugin allows the full configuration of the OPC UA Client Device Plugin.

The Node tree in the image above depicts the OPC UA Client Device Plugin's default Node tree. To set up one or more OPC UA Client Device Channels, add a Folder Node beneath the Node OPC UA Client Device/Channels (left picture). Afterward the default Node tree for a channel will apperar (right picture).

Now the settings for the specified channel can be changed. Also new variables can be created below the OPC UA Client Device/Channels/<Channel>/Variables folder. The link to the OPC Node will be granted using the Path property of the new variable Node.

The Path property has to be a validly formatted OPC NodeId, for example 2:Main-PLC/Office 1 - Lights/Front.

Every change in the Settings folder will apply as soon as the channel is restarted.

Every change in the Variables folder will automatically perform a reconfiguration of the OPC Client in the specified channel.

Change Settings

• Select the Settings property which shall be changed. (e.g. “Application/ServerAddress”)
• Click “Write a new Value”. (See example screenshot below)
• Enter the new value in the input field and save the changes.

Overview

Name	Type	Default Value	Description
Application
Application Name	String	Codabix	With this name the OPC UA Client will introduce itself to the OPC UA Server.
Server Address	String	opc.tcp://localhost:12345	The URL to the OPC UA Server. Possible protocols are: opc.tcp://, http://, https://, opc.com://. To access OPC Classic (COM) servers on Windows, use the format opc.com://<hostname>(:<port>)/<progId>/<classId>. The optional port number is used by the inline created wrapper server. In case the port number is missing it will be generated between 48000 and 48999 using the <classId>-value. Example for OPC Classic: opc.com://localhost:4711/OPCManager.DA.XML-DA.Server.DA/{E4EBF7FA-CCAC-4125-A611-EAC4981C00EA} Please note: In order to connect to OPC Classic Servers, the “OPC UA Gateway” component must not have been uninstalled in the Codabix Setup, and the option “Allow context-sensitive credentials” needs to be enabled in the Codabix Access Security settings. Additionally, the current version of OPC Core Components Redistributable (x86) needs to be installed.
Login Type	Enum	None	Defines which authentication type will be used. Valid Values: Anonymous, Certificate, UserPassword
Login Certificate	Blob		The certificate of the OPC UA Server used for the authentication. Can be uploaded as certificate file. (Has to contain the key of the certificate)
Login Name	String		The user of the OPC UA Server used for the authentication.
Login Password	String		The password for the given user of the OPC UA Server.
Session
Disconnect Timeout	Int32	10000	t.b.a.
Reconnect Timeout	Int32	10000	t.b.a.
Session Timeout	Int32	60000	t.b.a.
Use Break Detection	Boolean	True	Automatically detects if the connection to the OPC UA Server is interrupted. This is used for automatic reconnection if the connection to Server was lost. Valid Values: True, False
Security
Policy Algorithm	String	Auto	Valid Values: Auto, Basic128Rsa15, Basic256, Basic256Sha256, Custom, Https, None
Policy Level	Int32	0	t.b.a.
Policy Mode	String	None	Valid Values: None, Sign, SignAndEncrypt
Use Domain Checks	Boolean	False	Indicates if the OPC UA Client checks the OPC UA Server for a trusted certificate or not. This is a security feature to prevent e.g. man-in-the-middle attacks. Valid Values: True, False Attention If this option is set to true and the OPC UA Server doesn't have a trusted X.509 certificate (e.g. a self signed certificate) the connection will be rejected.
Use Secure Endpoint	Boolean	True	Indicates if the OPC UA Client shall check if the endpoint is secure or not. Some OPC UA Servers might not support this option. Valid Values: True, False
Certificate	Blob	<Blob>	The Client certificate. With this certificate the OPC UA Client will introduce itself to the OPC UA Server. A new certificate is created by default.
Transport
Channel Lifetime	Int32	600000	t.b.a.
Max Array Length	Int32	65535	t.b.a.
Max Buffer Size	Int32	65535	t.b.a.
Max Byte String Length	Int32	65535	t.b.a.
Max Message Size	Int32	1048576	t.b.a.
Max String Length	Int32	65535	t.b.a.
Operation Timeout	Int32	60000	t.b.a.
Security Token Lifetime	Int32	3600000	t.b.a.

Every Node beneath System/Devices/OPC UA Client Device/Channels/My Channel 1/Variables can be linked to an OPC Node from the OPC Server of the specified Channel using the Path property.

To connect a Codabix Node to an OPC UA Node the Path property has to be formatted as an OPC UA NodeId.

OPC NodeId

• Example NodeId: ns=2;s=Machine_1/IsActive

The specified NodeId is splitted in two parts: the Namespace Index and the Identifier of the OPC UA Node. The schema of a string identifier depends on the used OPC UA server.

• Namespace Index: ns=<Number> e.g. ns=2
• Separator: ;
• Identifier (String): s=<ParentNode1>/<ParentNode2>/…/<ParentNodeX>/<NodeName>

The plugin's device type OpcClientDevice also defines the OpcClientDeviceChannel and therefore extends the basic CodabixDevice and CodabixDeviceChannel entities. While the OpcClientDevice just represents a concretization of the CodabixDevice, the OpcClientDeviceChannel extends the CodabixDeviceChannel with the OPC UA Client Variable Entities.

Each channel is handled by a channel worker which establishes a physical connection to the OPC UA Server.

By default, the worker does not read any values. When a Client or plugin requests a synchronous read of the channel's variables in Codabix (e.g. using the Codabix Web Configuration's function “Read actual value”), the channel worker reads them from the underlying OPC UA Server and then writes them into the corresponding Codabix Nodes.

Similarly, when a Client or plugin writes values into the channel's variables, the channel worker will write those values to the underlying OPC UA Server.

To have an OPC UA Client variable being read steadily, you can edit the Node in the Configuration Web GUI and set “History Options” to Yes (which will create a subscription internally). In this case, the channel worker subscribes to the variables from the OPC Server (the OPC Client will get the new value from the OPC Server automatically if the value has been changed), and if the value of one of the variables has changed, writes the new value into the corresponding Codabix Node.