BS EN 61158-4-1:2014

0 INTRODUCTION
1 Scope
2 Normative references
3 Terms, definitions, symbols and abbreviations
4 Overview of the DL-protocol
5 General structure and encoding of PhIDUs and DLPDUs, and
   related elements of procedure
6 DLPDU-specific structure, encoding and elements of procedure
7 DLPDU-parameter structure and encoding
8 DL-service elements of procedure
9 DL-support subprotocol
10 Other DLE elements of procedure
11 PICS proforma
Annex A (informative) - Exemplary FCS implementation
Annex B (informative) - Type 1: Formal protocol finite state
        machines
Annex C (informative) - Type 1: DLPDU and DL-addressing
        short-form summaries
Bibliography
Annex ZA (normative) - Normative references to international
         publications with their corresponding
         European publications

Gives basic time-critical messaging communications between devices in an automation environment.

IEC 61158-4-1:2014 specifies procedures for the timely transfer of data and control information from one data-link user entity to a peer user entity, and among the data-link entities forming the distributed data-link service provider and the structure of the fieldbus DLPDUs used for the transfer of data and control information by the protocol of this standard, and their representation as physical interface data units. This second edition cancels and replaces the first edition published in 2007 and constitutes a technical revision. The main change is: Improved terms