The logical functionality of an AutomationComponent is represented by one or more FunctionalEntities described in 4.4. An important part of the functional model is the data exchange between FunctionalEntities using logical connections. Figure 8 illustrates this interaction.
Logical connections are configured using ConnectionConfigurationSets.
The following types of logical connections are supported (see Figure 10):
Bidirectional connections describe bidirectional data exchange between two FunctionalEntities.
Unidirectional connections with heartbeat describe unidirectional data exchange in one direction and a heartbeat message (for logical connection monitoring) in the opposite direction between two FunctionalEntities.
Unidirectional connections describe unidirectional data exchange between two FunctionalEntities.
Auditing reports problems and changes triggered by an external application. A subscription within a Connection is considered a source of data (for source of data, see OPC 10000-4). Changes in values of Variables from a data source do not generate Audit Events.