This part of IEC 61158 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. 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.
This standard defines in an abstract way the externally visible services provided by the Type
4 fieldbus data-link layer in terms of
a) the primitive actions and events of the services;
b) the parameters associated with each primitive action and event, and the form which they
take; and
c) the interrelationship between these actions and events, and their valid sequences.
The purpose of this standard is to define the services provided to
• the Type 4 fieldbus application layer at the boundary between the application and data-link
layers of the fieldbus reference model;
• systems management at the boundary between the data-link layer and systems
management of the fieldbus reference model.dition 2.0 2014-08 INTERNATIONAL STANDARD NORME INTERNATIONALE Industrial communication networks – Fieldbus specifications – Part 3-4: Data-link layer service definition – Type 4 elements Réseaux de communication industriels – Spécifications des bus de terrain – Partie 3-4: Définition des services de la couche liaison de données – Eléments de type 4 IEC 61158-3-4:2014-08(en-fr) THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright ？ <