Project Properties — OPC UA
Project Properties — OPC UA
OPC Unified Architecture (UA) provides a platform independent interoperability standard. It is not a replacement for OPC Data Access (DA) technologies: for most industrial applications, UA complements or enhances an existing DA architecture. The OPC UA Project Properties group displays the current OPC UA settings in the server.
Note: To change a setting, click in the specific property's second column. This invokes a drop-down menu that displays the options available.
Server Interface
Enable: When enabled, the UA server interface is initialized and accepts client connections. When disabled, the remaining properties on this page are disabled.
Log diagnostics: When enabled, OPC UA stack diagnostics are logged to the OPC Diagnostics Viewer. This should only be enabled for troubleshooting purposes.
Client Sessions
Allow anonymous login: This property specifies whether or not a user name and password are required to establish a connection. For security, the default setting is No to disallow anonymous access and require credentials to log in. Note: If this setting is disabled, users cannot login as the default user in the User Manager. Users can login as the Administrator provided that a password is set in the User Manager and is used to login.
Note: If this setting is disabled, users cannot login as the default user in the User Manager. Users can login as the Administrator provided that a password is set in the User Manager and is used to login.
Tip: Additional users may be configured to access data without all the permissions associated with the administrator account. When the client supplies a password on connect, the server decrypts the password using the encryption algorithm defined by the security policy of the endpoint, then uses it to login. Note: Users can login as the Administrator using the password set during the installation of Kepware Server to login. Additional users may be configured to access data without all the permissions associated with the administrator account. When the client supplies a password on connect, the server decrypts the password using the encryption algorithm defined by the security policy of the endpoint, then uses it to login.
When the client supplies a password on connect, the server decrypts the password using the encryption algorithm defined by the security policy of the endpoint.Max. connections: specify the maximum number of supported connections. The valid range is 1 to 256. The default setting is 128.
Tip: The maximum connections to UA servers is 256. The maximum number of UA Gateway instances is 128.Minimum session timeout: specify the UA client's minimum timeout limit for establishing a session. Values may be changed depending on the needs of the application. The default value is 15 seconds.
Maximum session timeout: specify the UA client's maximum timeout limit for establishing a session. Values may be changed depending on the needs of the application. The default value is 60 seconds.
Tag cache timeout: specify the tag cache timeout. The valid range is 0 to 60 seconds. The default setting is 5 seconds. Note: This timeout controls how long a tag is cached after a UA client is done using it. In cases where UA clients read / write to unregistered tags at a set interval, users can improve performance by increasing the timeout. For example, if a client is reading an unregistered tag every 5 seconds, the tag cache timeout should be set to 6 seconds. Since the tag does not have to be recreated during each client request, performance improves.
Note: This timeout controls how long a tag is cached after a UA client is done using it. In cases where UA clients read / write to unregistered tags at a set interval, users can improve performance by increasing the timeout. For example, if a client is reading an unregistered tag every 5 seconds, the tag cache timeout should be set to 6 seconds. Since the tag does not have to be recreated during each client request, performance improves.Browsing
Return tag properties: Enable to allow UA client applications to browse the tag properties available for each tag in the address space. This setting is disabled by default.
Return address hints: Enable to allows UA client applications to browse the address formatting hints available for each item. Although the hints are not valid UA tags, certain UA client applications may try to add them to the tag database. When this occurs, the client receives an error from the server. This may cause the client to report errors or stop adding the tags automatically. To prevent this from occurring, make sure that this property is disabled. This setting is disabled by default.
Monitored Items
Max. Data Queue Size: specify the maximum number of data notifications to be queued for an item. The valid range is 1 to 100. The default setting is 2. Note: The data queue is used when the monitored item's update rate is faster than the subscription's publish rate. For example, if the monitored item update rate is 1 second, and a subscription publishes every 10 seconds, then 10 data notifications are published for the item every 10 seconds. Because queuing data consumes memory, this value should be limited when memory is a concern.
Note: The data queue is used when the monitored item's update rate is faster than the subscription's publish rate. For example, if the monitored item update rate is 1 second, and a subscription publishes every 10 seconds, then 10 data notifications are published for the item every 10 seconds. Because queuing data consumes memory, this value should be limited when memory is a concern.Subscriptions
Max. retransmit queue size: specify the maximum number of publishes to be queued per subscription. The valid range is 1 to 100. A value of zero disables retransmits. The default setting is 10. Note: Subscription publish events are queued and retransmitted at the client's request. Because queuing consumes memory, this value should be limited when memory is a concern.
Note: Subscription publish events are queued and retransmitted at the client's request. Because queuing consumes memory, this value should be limited when memory is a concern.Max. notifications per publish: specify the maximum number of notifications per publish. The valid range is 1 to 65536. The default setting is 65536. Note: This value may affect the connection's performance by limiting the size of the packets sent from the server to the client. In general, large values should be used for high-bandwidth connections and small values should be used for low-bandwidth connections.
Note: This value may affect the connection's performance by limiting the size of the packets sent from the server to the client. In general, large values should be used for high-bandwidth connections and small values should be used for low-bandwidth connections. The Defaults button restores the settings to the default / pre-set values.