Glossary

In the following table the used terms and abbreviations regarding OPC UA are described.

Term Meaning
Monitored Item If an OPC UA item was added to a subscription this is a monitored item.
Address space

The collection of information that an OPC UA Server makes visible to its Clients.

The OPC UA address space consists of objects , types and views folders. Views (and thus also the views folder) are not supported by the WinCC OA OPC UA server/client.

OPC UA attribute A primitive characteristic of a Node. All Attributes are defined by OPC UA, and may not be defined by Clients or Servers. Attributes are the only elements in the Address Space permitted to have data values.
Certificate A digitally signed data structure that describes capabilities of a Client or Server.
Communication stack A layered set of software modules between the application and the hardware that provides various functions to encode, encrypt and format a Message for sending, and to decode, decrypt and unpack a Message that was received.
Node The fundamental component of an Address Space.
Subscription If the client wants to receive notifications on value changes or events, it has to create a subscription on the server. This subscription handles the processing of the notifications.
View A specific subset of the Address Space that is of interest to the Client.