3.1 Terms and definitions

For the purposes of this document, the terms and definitions given in OPC 10000-1, OPC 10000-3, and OPC 10000-4, as well as the following apply.

3.1.1 Action

an operation that is executed by a Responder when it receives a request message sent by a Requestor

Note 1 to entry:An Action is similar to a Method that can be invoked via PubSub.

3.1.2 DataSetClass

template declaring the content of a DataSet

Note 1 to entry:A DataSetClass is used to type DataSets for use in several Publishers and for filtering in Subscribers.

3.1.3 DataSetMetaData

data describing the content and semantic of a DataSet

3.1.4 DataSetReader

entity receiving DataSetMessages from a Message Oriented Middleware

Note 1 to entry:A DataSetReader is the component that extracts a DataSetMessage from a NetworkMessage received from the Message Oriented Middleware and decodes the DataSetMessage to a DataSet for further processing in the Subscriber.

3.1.5 DataSetWriter

entity creating DataSetMessages from DataSets and publishing them through a Message Oriented Middleware

Note 1 to entry:A DataSetWriter encodes a DataSet to a DataSetMessage and includes the DataSetMessage into a NetworkMessage for publishing through a Message Oriented Middleware.

3.1.6 Requestor

an entity that initiates an Action by sending a request to a Responder

Note 1 to entry:The Requestor uses metadata provided by the Responder to build request messages (ActionRequest) and to parse response messages (ActionResponse).

3.1.7 Responder

an entity that executes an Action when a request is received from a Requestor

Note 1 to entry:The Responder publishes metadata describing the Actions that it supports.

Note 2 to entry:The Responder sends a response to Requestor when the Action completes.

3.1.8 PublishedDataSet

configuration of application-data to be published as DataSet

Note 1 to entry: A PublishedDataSet can be a list of monitored Variables or an Event selection.

3.1.9 SecurityGroup

grouping of security settings and security keys used to access messages from a Publisher

Note 1 to entry:A SecurityGroup is an abstraction that represents the security settings and security keys that can be used to access messages from a Publisher. A SecurityGroup is identified with a unique identifier called the SecurityGroupId. The SecurityGroupId is unique within the Security Key Service.

3.1.10 SubscribedDataSet

configuration for dispatching of received DataSets

Note 1 to entry: A SubscribedDataSet can be a mapping of DataSet fields to Variables in the Subscriber AddressSpace.