OPC Alarms/Events Servers (AE Servers)

AE servers can record values from different data sources, evaluate it, and decide whether an event occurred. An SAP system can use SAP ODA to subscribe to certain events. The AE server informs the SAP system that an event occurred, for example, that the temperature has risen above a certain limit.

See also: Event Subscription

Filter Criteria

AE servers can provide a number of different events but not all events are interesting for the OPC client. To reduce the number of events to be reported, you can define filter criteria in Customizing for the SAP system.

The following filter criteria are available:

Event Areas

To arrange events topographically, they are structured in event areas. An event area comprises the namespace in which the events may occur and that can be set up in the AE server. The nodes of the event areas indicate the areas in which events may occur. The leaves represent the sources from which the event information comes (for example, machine). Several events (for example, monitoring the temperature value and temperature sensor) can be defined at a source.

Example Example

The following example shows the event area Production building #1 . The next nodes represent the production lines.

  • Node Production line #2 also has the node Machine #30 . Machine #30 has the event sources Temperature and Alarm. Temperature is a condition-related event with the condition Level and the relevant subconditions. Alarm is a simple event.

  • The node Production line #3 has the event source Vessel valve #75 . Vessel valve #75 is a condition-related event with the condition Contact and the subcondition Open .

End of the example.
Event Types

To arrange events in a logical structure, they are divided into event types. The following event types are distinguished:

  • Simple events

    These event types inform the system that an event has occurred (for example, a device failure). The event message contains general information such as the event time, event type, event severity, event category, event source, and the event text (see below).

  • Tracking-related events

    Beside the information contained in simple events, this event type also contains the actor ID, that identifies, for example, the batch number or the person who triggered the OPC event.

  • Condition-related events

    With this event type, it is defined in the OPC server under which conditions an event is to be triggered. This is defined using conditions and its subconditions. The subconditions can describe a reason (for example, pressing a button) or several reasons (for example, value is above or below a limit) for an event. By activating and deactivating the subconditions, you control which events the OPC server sends to the SAP system. In addition, the OPC server can request an acknowledgement of the reported events by the SAP system.

    Example: The condition-related event “Door” has the condition “Contact” and the subcondition “Opening Door”.

    Events of the type Condition-related can contain conditions and subconditions that can be activated and deactivated. AE servers only report those events that match the activated subconditions.

Event Category

The event types are again subdivided into event categories. Examples of event categories would be, for example, device error and system error.

Event Severity

You can assign a severity from 1 (low) to 1000 (high) to every event.

Example of the Filter Criteria for Event Types