EN 61158-3-7:2008

INTRODUCTION
1 Scope
  1.1 Overview
  1.2 Specifications
  1.3 Conformance
2 Normative references
3 Terms, definitions, symbols, abbreviations and conventions
  3.1 Reference model terms and definitions
  3.2 Service convention terms and definitions
  3.3 Data-link service terms and definitions
  3.4 Symbols and abbreviations
  3.5 Common conventions
4 Data-link layer services and concepts
  4.1 Field of application, object
  4.2 General description of services
  4.3 Sequences of primitives
  4.4 Buffer writing
  4.5 Buffer reading
  4.6 Buffer transfer
  4.7 Explicit request for buffer transfer
  4.8 Unacknowledged message transfer
  4.9 Acknowledged message transfer
Bibliography
Annex ZA (normative) - Normative references to international
                       publications with their corresponding
                       European publications

It 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. It includes the following significant changes with respect to the previous edition deletion of the former Type 6 fieldbus, and the placeholder for a Type 5 fieldbus data-link layer, for lack of market relevance; addition of new types of fieldbuses; division of this part into multiple parts numbered.