OPC Alarms & Events, basics

OPC Alarms & Events (brief OPC A&E) is in addition to the Data Access another standard in order to implement a central alert management manufacturer spanning. OPC A&E is used to guarantee the coupling with other control systems as well as to display alerts and events in a hierarchical system. WinCC OA differentiates between server and client when using OPC A&E:

WinCC OA OPC A&E server: WinCC OA provides alert data to higher-level third party systems and accepts acknowledgements from the third party systems.

WinCC OA OPC A&E client: Secondary systems return alert data in WinCC OA - these are shown centrally and processed (the acknowledgements are passed on to secondary systems).

As an example the OPC A&E server could be used in the topmost level of a hierarchical structure and could provide alert data to OPC A&E clients of other producers or the WinCC OA OPC A&E client. The WinCC OA OPC A&E server and client do not obligatory have to be used for the communication. Arbitrary other OPC A&E servers can communicate with the WinCC OA OPC A&E client and vice versa. The use of OPC A&E guarantees consistent display on all hierarchical layers, irrelevant where an alert was acknowledged. Furthermore, you have to consider that the OPC A&E does not acknowledge the alert self  but only send the information to the OPC A&E server, which then acknowledges the alert.

OPC (OLE for Process Control) means the use of OLE/COM technology for control systems. The specifications used for this purpose are specified by the OPC foundation (http://www.opcfoundation.org). The specification documents cover several category groups:

• Data Access (for more information on the OPC Data Access in WinCC OA, see chapter OPC, basics)

• Historical Data Access

• Alarms & Events

This documentation covers the most important concepts and the basic functionality of OPC A&E with WinCC OA. For detailed information on the functionality of the OPC A&E communication, particularly  the use of all parameters, see the documentation of the used server or client and/or the OPC Alarms&Events specification.

The interaction of WinCC OA and OPC A&E is described in more detail in the chapter Functionality and concept description.