Opc Ua Events; Description Of The Events - Siemens SIMATIC RF185C Operating Instructions Manual

9.3

OPC UA events

9.3.1

Description of the events

OPC UA variables represent a simple way to query or accept information from the
communications modules.
The known difficulties in time-based synchronization between the query and update of the
variable values during more complex process with OPC UA variables do not occur with
events. If events are defined for specific actions, an independent event is generated for each
action that has occurred and been completed. Overwriting the related information is
excluded.
With events, in contrast to variables with their simple data types, OPC UA clients require the
possibility to handle more complex data types such as structures and unions in addition.
The integrated OPC UA servers of the RF18xC communications modules offer the following
three additional events as a supplement to the AutoID standard:
● AutoIdPresenceEvent
● RfidLastAccessEvent
● AutoIdLastLogEntryEvent
These three events are for diagnostics purposes. These events are derived directly or
indirectly from the "AutoIdDiagnosisEvent" event, which in turn is derived from "BaseEvent"
with its properties as defined in the OPC UA standard.
Figure 9-3
SIMATIC RF185C, RF186C, RF188C
Operating Instructions, 10/2018, C79000-G8976-C512-01
Derivations of the OPC UA events based on the "BaseEvent"
Programming via the OPC UA interface
9.3 OPC UA events
105