Usage considerations

FactoryTalk Linx

OPC

UA Connector can be added to applications or areas in a

FactoryTalk

Network Directory or a

FactoryTalk

Local Directory.

A maximum of 20

OPC

UA Servers can be connected to a single OPC UA Connector. To use more than 20 OPC UA Servers or to spread the system resource load across multiple host computers, add multiple

OPC

UA Connectors to a

FactoryTalk

application.

OPC UA Connectors and OPC UA Servers must communicate over an IPv4 network. IPv6 connectivity is not supported.

OPC UA Servers must communicate using the

opc.tcp://

protocol. Other protocols, such as

http://

and

https://

are not supported.

OPC UA Servers must support subscriptions with poll rates to read tags. Read requests are not supported.

OPC UA Servers that impose limits on the number of items that can be incorporated into a single subscription may not work as expected. All items monitored at the same rate are added to the same subscription. If the number of items in one subscription exceeds an OPC UA Server limit, items in the subscription may fail.

If an established subscription is disconnected, it is retained and can be reconnected if the communication recovers within 10 minutes. If the disconnection lasts more than 10 minutes, a new connection request will be submitted for the client to establish the connection.

After the initial OPC UA Server connection or after refreshing tag names, there is a delay before all server tags appear in the

FactoryTalk

Tag Browser. The delay time is dependent on OPC UA Server specifications, network specifications, and the data model of the tags provided to the OPC UA Connector.

To determine if the tag name upload is complete, monitor the

@OPC_NamespaceCacheUploadCompleteStatus

predefined diagnostic item of the OPC UA server.

To determine if an error has occurred during the tag name upload, view

FactoryTalk Diagnostic Log

.

The OPC UA Connector performance of namespace processing and browsing is better when using the network scope than using the local scope.

Server names, folder names, or node ID names containing a forward slash (/) are not supported.

FactoryTalk OPC UA Connector uses TCP ports on the target workstation hosting the OPC UA Server to be open and accessible. Review the OPC UA Server's configuration and ensure that any TCP ports are opened and available for communications. It might be necessary to modify the workstation operating system and firewall. For more information, refer to Knowledgebase Document ID: IN40928 - Security Software Considerations to Prevent or Mitigate Impacts to Rockwell Automation Software Products.

FactoryTalk Linx

OPC UA Connector new features supported by

FactoryTalk Services Platform

version 6.10.00 cannot be configured or used by computers running

FactoryTalk Services Platform

version 3.00.00 or earlier. To use these features, update

FactoryTalk Services Platform

on all computers hosting

FactoryTalk Linx

OPC UA Connectors to version 6.10.00 or later.

To use the redundancy capability of

FactoryTalk Linx

OPC UA Servers, use

FactoryTalk Services Platform

version 6.20.00 or later.

Data coming from an OPC UA Server, delivered through the OPC UA Connector, may not update even though the OPC UA Server delivers new values. The OPC UA Connector evaluates a time stamp provided with the data value to help prevent delivering data that is older than a previous value. If an OPC UA Server sends a value with a time stamp older than a previous value, the OPC UA Connector ignores it, indicating that that there may be a problem with the OPC UA Server or device. First identified in

FactoryTalk Linx

OPC UA Connector version 6.20.00.

When a variable node’s datatype is defined as a Structure (NodeId: i=22),

FactoryTalk Linx

OPC UA Connector will identify it as a folder instead of a data item. If you do a namespace analysis, all such tags will be identified as "folder (raw 'Structure' type (i=22) not supported)."

An OPC UA Server can define structures to send structure values as both encoded data containing all fields and separate values for each individual field.

FactoryTalk Linx

OPC UA Connector can read the values for both types, but it cannot write values to fields within the encoded data. If the value is accessed as encoded data, it is read-only, and the tags representing a structure’s fields within the encoded data are shown in FactoryTalk software with periods (".") between each structure level. If a structure value is accessed as individual fields,

FactoryTalk Linx

OPC UA Connector can write values to it, and the tags representing a structure’s fields are shown in FactoryTalk software with slashes ("\") between each structure level.