OPC UA Server Configuration

Introduction

The OPC UA Server Configuration window allows you to configure the OPC UA server. By default the OPC UA server is using encrypted communication with maximum security settings.

Optionally, you can customize the OPC UA server name via the post configuration. Refer to Parameters.

Accessing the OPC UA Server Configuration Tab

To configure the OPC UA Server:

Step	Action
1	In the Devices tree, double-click MyController.
2	Select the OPC UA Server Configuration tab.

OPC UA Server Configuration Tab

The following figure shows the OPC UA Server Configuration window:

OPC UA Server Configuration Description

This table describes the OPC UA Server Configuration parameters:

Security Settings
Parameter	Value	Default value	Description
Disable anonymous login	Enabled/ Disabled	Disabled	By default, this checkbox is cleared, meaning that OPC UA clients can connect to the server anonymously. Select this checkbox to require that clients provide a valid user name and password to connect to the OPC UA server.
Security Policy	None Basic256(deprecated) ⁽¹⁾ Basic256Sha256	Basic256Sha256	This drop-down menu allows you to sign and encrypt the data you send and receive.
Message Security	None Sign SignAndEncrypt	SignAndEncrypt	The messages are related to the selected Security Policy.
(1) Security policies marked as deprecated are policies which no longer afford an acceptable level of security.

Server Configuration
Parameter	Value	Default value	Description
Server port	0...65535	4840	The port number of the OPC UA server. OPC UA clients must append this port number to the TCP URL of the controller to connect to the OPC UA server.
Max. subscriptions per session	1...100	20	Specify the maximum number of subscriptions allowed within each session.
Min. publishing interval	200...5000	1000	The publishing interval defines how frequently the OPC UA server sends notification packages to clients. Specify the minimum time that must elapse between notifications, in ms.
Max. monitored items per subscription	1...1000	100	The maximum number of monitored items in each subscription that the server assembles into a notification package.
Min. KeepAlive interval	500...5000	500	The OPC UA server only sends notifications when the values of monitored items of data are modified. A KeepAlive notification is an empty notification sent by the server to inform the client that although no data has been modified, the subscription is still active. Specify the minimum interval between KeepAlive notifications, in ms.
Max. number of sessions	1...4	2	The maximum number of clients that can connect simultaneously to the OPC UA server.
Identifier type	Numeric String	Numeric	Certain OPC UA clients require a specific format of unique symbol identifier (node ID). Select the format of the identifiers: Numeric values Text strings

Diagnostic
Parameter	Value	Default value	Description
Enable trace	Enabled/disabled	Enabled	Select this checkbox to include OPC UA diagnostic messages in the controller log file. Traces are available from the Log tab or from the System Log File of the Web Server. You can select the category of events to write to the log file: None Error Warning System Information Debug Content All (default)

Sampling rates (ms)
Parameter	Value	Default value	Description
Sampling rates (ms)	200...5000	500 1000 2000	The sampling rate indicates a time interval, in milliseconds (ms). When this interval has elapsed, the server sends the notification package to the client. The sampling rate can be shorter than the publishing interval, in which case notifications are queued until the publishing interval has elapsed. Sampling rates must be in the range 200...5000 (ms). Up to 3 different sampling rates can be configured. Double-click on a sampling rate to edit its value. To add a sampling rate to the list, right-click and choose Add a new rate. To remove a sampling rate from the list, select the value and click .

Click Reset to default to return the configuration parameters on this window to their default values.

Client Certificates Management Actions

The Security Screen allows you to determine which OPC UA client certificates are trusted by the OPC UA server.

To access the Security Screen, use the View > Security Screen command.

The first attempt of the client connection is unsuccessful as the certificate is quarantined. To allow the OPC UA server to accept a client certificate, proceed as follows:

NOTE: Start from step 6 if you already have the trusted certificate.

Step	Action
1	In the Devices tab of the Security Screen, click the Refresh button to update the list of available devices and their certificate store.
2	Select the device entry (device name) on the left side.
3	Open the Quarantined Certificates. Quarantined certificates are listed in the table with the symbol.
4	Click the Properties button to show details for the selected certificate. Inspect the certificate details. If it is trusted, proceed to the next step.
5	Upload the selected certificate from the device and save it to your PC by clicking the Upload button .
6	Open the Trusted Certificates. Trusted certificates are listed in the table with the symbol. (By default, no certificate is available).
7	Click the Download button and select your trusted certificate. Result: The downloaded certificate is stored and listed in the Trusted Certificates table. The OPC UA server is then able to accept the client connection with the correct Security Settings.