This specification defines two main ObjectTypes:

• an instance of CalendarType represent a globally defined set of dates that can be referenced by schedule Objects;
• an instance of ScheduleType represent a schedule, that defines for specific dates or weekdays specific times and actions, that shall be executed at those times.

An overview is given in Figure 1. Instances of ScheduleType can have a WeeklySchedule, defining per weekday specific times and per specific time a list of actions that shall be executed at that time. Optionally, the WeeklySchedule can be configured by OPC UA Clients.

In addition, or as alternative, a schedule Object can have a ExceptionSchedule. This defines special dates (days), either by defining a concrete date, a range of dates, or recurring dates, or by referencing instances of CalendarType. The optional Methods AddExceptionScheduleElements and RemoveExceptionScheduleElements can be used to configure the ExceptionSchedule by an OPC UA Client.

Figure 1 – Overview Scheduler Information Model

The CalendarType defines a DateList with specific dates. The optional AddDateListElements and RemoveDateListElements Methods can be used to manipulate the DateList Property by OPC UA Clients.

This specification does not define any specific entry points where to find schedule or calendar Objects. It is expected that they are placed reasonable in the AddressSpace, for example as child Object of an Object that is manipulated by actions of the schedule Object.

This specification does not define any specific mechanism how new schedule or calendar Objects are added or removed via OPC UA. Information Models using those Objects might define specific mechanisms like Methods or using the NodeManagement Service Set.