'Client Connections' Editor (OPC UA)

The following information refers to a specific, typical device type. Your screen may differ.

This help topic describes the 'Client Connections' editor of the 'OPC UA' PLANT node. Here, you can configure the OPC UA server connections and map the variables (process data items) declared in the PLCnext Engineer project to the OPC UA server variables. The configuration is stored to an XML file on the PLCnext Technology controller. The file is based on the standard UA schema for data types.

Further Info
Details and procedures can be found in the help chapter "Configuring the OPC UA Client Connections".

On the left side on the 'Client Connections' page, several editor categories can be selected. These are described below in detail.

This topic contains the following sections:

Note
The categories are structured hierarchically. New subcategories of the top category are added after you have defined a new data set. To expand a category, click the icon of the entry.

'Configurations'

'Server' table

Table for configuring the OPC UA server connections. Each table row represents a server connection.

Column Description

Name Name that identifies the server connection that is used for the data exchange. The connection must be specified for each variable mapping you create (see table "Variable Mappings" below).

URL Endpoint URL of the OPC UA server to connect to. The client uses the URL to find and connect to the OPC UA server. The format is as follows (see also the examples in the figure above):
opc.tcp://IpAddress:Port
or
opc.tcp://hostname:Port
Optionally the port can be specified. If omitted, the default OPC UA discovery port 4840 is used.

Note
Currently, only the endpoint type opc.tcp is supported.

Username (Optional) User name to authenticate with the OPC UA server. If no username is entered, anonymous authentication towards the server is enabled.

Password (Optional) Password to authenticate with the OPC UA server. Only required if the username is specified.

Security mode Security mode used to connect to the OPC UA server. The security mode defines the level of security for the data being exchanged during client-server communication. You can choose one of the following modes:

'None' - No security is applied. Data are exchanged unsecure.

'Sign' - Data are signed but not encrypted.

'Sign and Encrypt' - Data are signed and encrypted.

Security policy url Security policy url used to connect to the OPC UA server. The security policy describes various algorithms and key lengths which are used to establish a secure connection between server and client. In accordance with the OPC UA specification, you can choose one of the following security policies (from top to bottom, the encryption and signature strength increases):

'None' - No security is applied.

'Basic 128 RSA15'

'Basic 256'

'Basic 256 SHA256'

'AES 128 SHA256 RSA OAEP'

'AES 256 SHA256 RSA PSS'

'Best available' - Best available security policy provided by the OPC UA server is used.

Further Info
See also the 'Security Policies' descriptions in the "OPC UA Security Settings" topic.

'Variable Groups' table

In this table you can add and configure variable groups.

Within each group local variables (variables defined in the PLCnext Engineer project) can be mapped to the remote server variables. Via this mapping data between client and server can be exchanged. A variable group can contain one or more variable mappings.

The OPC UA client either subscribes to the variables of the remote OPC UA server or writes the changed values of the local variables to the remote server variables.

Column Description

Cycle Time [ms] Enter a cycle time value (value must be greater or equal to 1). This value specifies in which interval (in [ms]) the variable group you are defining is subscribed or published.

Type Drop-down list for specifying whether the variable group is to be subscribed or published by the client.

Column	Description
Cycle Time [ms]	Enter a cycle time value (value must be greater or equal to 1). This value specifies in which interval (in [ms]) the variable group you are defining is subscribed or published.
Type	Drop-down list for specifying whether the variable group is to be subscribed or published by the client.

'Variable group [Type/Cycle Time]'

'Variable Mappings' table

A new variable group appears under the 'Configuration' category on the left in the editor after you have confirmed the cycle time value. The group name shows the configured group type and cycle time.

After selecting the 'Variable group' entry on the left border of the editor, the 'Variable Mapping' table with the variable properties becomes visible and can be edited.

Column Description

Local variable Local variable to be mapped to the OPC UA server variable.
Click into an empty cell and select the desired variable from the variables list. The selection list provides all variables/ports declared in your PLCnext Engineer project (except variables of the type STRING and STRUCT). (As long as no 'Remote variable identifier' is entered, the mapping is invalid.)

Data type Read-only data type of the local variable.

Server OPC UA server connection to be used for the data exchange.
Select a connection from the connections list. The list provides all server connections you have configured in the server table (see above).

Remote variable identifier Type of the identifier of the NodeId.
Example: I=10
Further information can be found in the section "Data exchange between OPC UA client and OPC UA server".

Remote variable namespace Namespace to which the node representing the OPC UA server variable belongs.
Example: http://phoenixcontact.com/OpcUA/PLCnext/GlobalDataSpace/

Column	Description
Local variable	Local variable to be mapped to the OPC UA server variable. Click into an empty cell and select the desired variable from the variables list. The selection list provides all variables/ports declared in your PLCnext Engineer project (except variables of the type STRING and STRUCT). (As long as no 'Remote variable identifier' is entered, the mapping is invalid.)
Data type	Read-only data type of the local variable.
Server	OPC UA server connection to be used for the data exchange. Select a connection from the connections list. The list provides all server connections you have configured in the server table (see above).
Remote variable identifier	Type of the identifier of the NodeId. Example: I=10 Further information can be found in the section "Data exchange between OPC UA client and OPC UA server".
Remote variable namespace	Namespace to which the node representing the OPC UA server variable belongs. Example: http://phoenixcontact.com/OpcUA/PLCnext/GlobalDataSpace/