Configuration

Enable data collection

Enables or disables data collection for this OPC UA Client instance.

Subscription batch size

Indicates the batch size rate for adding subscriptions to the OPC UA server. The default value is 5000.

Subscription batch delay

Sets the delay between two subscription batches. The default value is 0.

Max. items per subscription

The maximum number of monitored items per subscription to the server. If there are more monitored items than this value, multiple subscriptions will be used.

Note:

This feature is available from N3uron version 1.21.9.

Data change filter

Selects when events should be reported by the server. This affects all monitored items created by this client. The default value is Status/Value. The available options are:

• Status/Value: Only changes in either the Status or Value of the selected node will be reported.

• Status/Value/Timestamp: Changes in either the Status, Value, or Timestamp of the selected node will be reported.

• Expression: Allows a custom expression to be used to define the data change filter. Intended to be used with Templates.

Note:

The Data change filter setting is available from N3uron version 1.22.4.

Override timestamps

When enabled, timestamps received from the server will be overwritten using the local time.

Discovery URL

Enter the URL for the OPC UA server's discovery endpoint, which is used to locate available connection endpoints and their configurations. The format should be as follows: opc.tcp://IPAddress:port or opc.tcp://myServer:port.

Note:

If the server's endpoint and discovery URLs are the same, use the same URL in both fields. Some OPC UA servers separate the discovery and server endpoints, requiring different URLs. We recommend using the OPC UA Server Discovery utility, which automatically configures the Discovery URL, Endpoint URL, Security Mode, and Security Policy.

Note:

This feature is available from N3uron version 1.21.11.

Endpoint URL

Enter an OPC UA endpoint URL for the specific OPC UA Server that N3uron should connect to. The format should be as follows: opc.tcp://IPAddress:port or opc.tcp://myServer:port. Example: opc.tcp://192.168.0.1:3005. The option to browse and discover an endpoint is available by clicking on the button of the OPC UA Server discovery utility.

Note:

The Security mode and Security policy fields are automatically filled in when the endpoint is selected from the discovery interface.

Endpoint must exist

If Enabled, the OPC UA Client will verify that the hostname specified in the "Server Certificate" is the same as the hostname provided in the "Endpoint URL" to permit the connection. The default value is Disabled.

Security mode

Specifies the type of encryption used when exchanging messages between the OPC UA Client and Server. By default, it is set to Sign & Encrypt. The available options are:

• None: There will be no security at all and should only be used for testing purposes.

• Sign: This option is sufficient if data confidentiality is not a requirement.

• Sign & Encrypt: This is the most secure option and therefore, the most recommended.

• Expression: This option allows for a custom expression to be used to define the security mode. Intended to be used with Templates.

Security policy

Specifies which security mechanism should be used. By default, this is set to Basic 128 & Rsa 15. Supported algorithms are as follows:

• None

• Basic 128 & Rsa 15 (deprecated since OPC UA Specification Version 1.04)

• Basic 256 (deprecated since OPC UA Specification Version 1.04)

• Basic 256 & Sha 256

• Expression: This option allows for a custom expression to be used to define the security policy. Intended to be used with Templates.

Requested session timeout

Sets the amount of time a session must be idle before it times out. In general, we recommend you use a high enough value so that the session never times out. The value entered should be at least double the sum of multiplying the publishing interval with the subscription keep-alive count value. The default value is 3,600,000ms.

Reconnect delay

Specifies the wait time before attempting to reconnect after a failed connection attempt, displayed in milliseconds. The minimum value is 1,000ms and the default value is 5,000ms.

Enabled

When Enabled, users will need to introduce valid credentials to access the server.

User

Specifies the user name to authenticate with the server.

Password

Specifies the password used to authenticate with the server.

Note:

All passwords will be encrypted for security reasons.

Publishing interval

Defines how frequently the OPC UA server will send notification packages and specifies the necessary elapsed time between notifications, displayed in milliseconds. The default value is 1,000ms.

Lifetime count

Number of publishing intervals until the subscription is deleted by the server if no publish request has been received. The default value is 60.

Max. keepalive count

When the server publishing timer surpasses the number of attempts specified here without any data to be sent, the subscription will send a keep-alive message to the client. The default value is 10.

Max. notifications per publish

Establishes the maximum number of notification events per publish request. This can be used to help reduce peaks in communication load when transmitting buffered data. The default value is 10,000. A value of 0 means that the client specifies no limit and the server will use the maximum number of notifications per publish.

Enabled

When Disabled, tags won't be updated with the values received from the server, but instead, will essentially act as memory tags. When set to Enabled, the tag value will be continuously updated with the values received from the OPC UA Server. The default value is set to Disabled.

Module type

Defines the driver type used to retrieve values. In this example, OpcUaClient must be selected from the drop-down menu. If OpcUaClient does not appear in the drop-down menu, it means that this functionality has not yet been installed on this machine and therefore, must be installed.

Module name

Users should enter here the name of the OPC UA Client module instance that was previously created.

OPC UA Client

This section represents the link between the tag and its data source. Therefore, it must be filled in with the name of the Client that was previously created. In the above example, we used Client01.

Node ID

Specifies the OPC item path. According to the OPC UA specification, the Node ID is made up of the Namespace index (ns), an Identifier Type and the Identifier. The following table shows some examples:

s

String

ns=2; s=MyTemperature

i

Integer

ns=2; i=133

g

GUID

ns=2; g=123E4567-E89B-12D3-A456-426614174000

b

ByteString

ns=2; b=01020304050607

Scalar

Specifies whether the type of data is a scalar value.

Array

Specifies whether the type of data is an array value. The array can have any number of dimensions.

Struct

Specifies whether the type of data is a struct or an array of structs. It is an object whose properties must be accessed in a nested way (prop1.prop2 or prop1[index].prop2).

Convert to JSON string

The expected value can have any structure and this structure will be converted to JSON. For this to be valid, the tag type must be string.

Scan rate

Sampling interval request for the tag, displayed in milliseconds. The minimum value is 100ms and the default value is 5,000ms.

Discard oldest

When Enabled, the oldest events will be deleted to allocate space for the latest events in the buffer.

Queue size

Specifies the size of the buffer for storing received events. The default value is 10.