BS EN 61158-3-12 is the 12th 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 61158-3-12 defines in an abstract way the externally visible service provided by the Type 12 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 61158-3-12 on data-link layer service definition is useful for:
BS EN 61158-3-12 define the services provided to the Type 12 Fieldbus application layer at the boundary between the application and datalink 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 principal objective of BS EN 61158-3-12 is to specify the characteristics of conceptual data-link layer services suitable for time-critical communications, and thus supplement the OSI Basic Reference Model in guiding the development of data-link protocols for time-critical communications.
A secondary objective of BS EN 61158-3-12 is to provide migration paths from previously-existing industrial communications protocols
EN 60644:2009
EN 61158-3-12:2014
IEC 61158-3-12:2014