IEC 61158-4-2:2019

IEC 61158-4-2:2014 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 third edition cancels and replaces the second edition published in 2010 and constitutes a technical revision. The main changes are: - Addition of conventions in 3.6; - Updates of ControlNet object in 7.2; - Addition of missing V/NV attribute characteristic in 7.5, 7.6, 7.7; - Extensions and clarifications of TCP/IP interface object in 7.5; - Extensions and clarifications of Ethernet Link object in 7.6; - Extensions and clarifications of CCO object in 7.8; - Extensions and updates of DLR object in 7.9; - Updates of QoS object in 7.10; - Addition of Port object in 7.11; - Updates to DL state machines in 8.1 and 9.2; - Extensions and updates of DLR protocol in Clause 10; - Update of indicator behavior in A.2.2 and A.2.3.

IEC 61158-4-2:2023 is one of a series produced to facilitate the interconnection of automation system components. It is related to other standards in the set as defined by the "three-layer" fieldbus reference model described in IEC 61158?1. The data-link protocol provides the data-link service by making use of the services available from the physical layer. The primary aim of this document is to provide a set of rules for communication expressed in terms of the procedures to be carried out by peer data-link entities (DLEs) at the time of communication. These rules for communication are intended to provide a sound basis for development in order to serve a variety of purposes: - as a guide for implementers and designers; - for use in the testing and procurement of equipment; - as part of an agreement for the admittance of systems into the open systems environment; - as a refinement to the understanding of time-critical communications within OSI.