OPC UA Part 1 - Overview and Concepts 1.02 Specification(10)

OPC UA Specification Part1 OverView and Concepts

OPC Unified Architecture, Part 1 2 Release 1.02 3.1 OPC UA terms

3.1.1 AddressSpace

The collection of information that an OPC UA Server makes visible to its Clients. See Part 3 for a description of the contents and structure of the Server AddressSpace.

3.1.2 Alarm

A type of Event associated with a state condition that typically requires acknowledgement. See Part 9 for a description of Alarms.

3.1.3 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 AddressSpace permitted to have data values.

3.1.4 Certificate

A digitally signed data structure that describes capabilities of a Client or Server.

3.1.5 Client

A software application that sends Messages to OPC UA Servers conforming to the Services specified in this set of specifications.

3.1.6 Condition

A generic term that is an extension to an Event. A Condition represents the conditions of a system or one of its components and always exists in some state.

3.1.7 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.

3.1.8 Complex Data

Data that is composed of elements or more than one primitive data type, such as a structure.

3.1.9 Discovery

The process by which OPC UA Clients obtain information about OPC UA Servers, including endpoint and security information.

3.1.10 Event

A generic term used to describe an occurrence of some significance within a system or system component.