BS EN 61158-3-2 is the second subpart of the third part of the multiple series that provides common elements for basic time-critical messaging communications between devices in an automation environment. The term “time-critical” is used to represent the presence of a time window, within which one or more specified actions are required to be completed with some defined level of certainty.
BS EN 61158-3-2 defines in an abstract way the externally visible service provided by the Type 2 Fieldbus data-link layer in terms of:
Note: Failure to complete specified actions within the time window risks failure of the applications requesting the actions, with attendant risk to equipment, plant and possibly human life.
BS EN 61158-3-2 on data-link layer service definition is useful for:
BS EN 61158-3-2 defines the services provided to the Type 2 Fieldbus application layer at the boundary between the application and data-link layers of the Fieldbus reference model and systems management at the boundary between the data-link layer and systems management of the Fieldbus reference model.
The main goal of BS EN 61158-3-2 is to define the features of conceptual data-link layer services that are suitable for time-critical communications, in order to augment the OSI Basic Reference Model in directing the development of data-link protocols for time-critical communications.
A secondary goal of BS EN 61158-3-2 is to enable migration paths from other industrial communication protocols.
EN 60704-2-2:2010
EN 61158-3-2:2014
IEC 61158-3-2:2014