The ConnectionConfigurationSetType is an ObjectType representing one or more Connection configurations. Connections are grouped in a set, for example, to allow sharing communication model configurations by multiple Connections; see 18.104.22.168.3 and 22.214.171.124.4 for appropriate use cases.
If a ConnectionConfigurationSet is exposed in the AddressSpace, its representation serves two purposes: making Connection configurations available for modification by standard Clients (see Figure 11 label 4) and providing an interface to trigger the processing of such Connection configurations.
- The SelectionListType (see OPC 10000-5) is used to indicate where support for modifications is required. This type allows the generator of the ConnectionConfigurationSet to provide a list of Selections and an optional description of them. If the optional RestrictToList is set to TRUE, a Client changing the Variable is restricted to the provided Selections. If set to FALSE or missing, a Client may change the Variable to any value, including one of the Selections. For example, an engineering tool may restrict the PublishingInterval to the values 2 ms, 4 ms, and 8 ms by adding these values to Selections and setting RestrictToList to TRUE. If the vendor does not wish to have any changes made, they shall configure the value of the SelectionListType to the desired fixed value, they shall populate the Selections list with the same value, and they shall set the RestrictToList to TRUE.
- Data that has been set to ReadWrite for specific users or in general. This can be determined by examining the AccessLevel and UserAccessLevel Attributes of the data.
With these mechanisms, the generator of the ConnectionConfigurationSet is able to specify and restrict the allowed changes.