IEC 61158-4-3:2014

IEC 61158-4-3:2010 describes the protocol that provides communication opportunities to a pre-selected "master" subset of data-link entities in a cyclic asynchronous manner, sequentially to each of those data-link entities. Other data-link entities communicate only as permitted and delegated by those master data-link entities. For a given master, its communications with other data-link entities can be cyclic, or acyclic with prioritized access, or a combination of the two. This protocol provides a means of sharing the available communication resources in a fair manner. There are provisions for time synchronization and for isochronous operation. This second edition cancels and replaces the first edition published in 2007 and constitutes a technical revision. The main changes with respect to the previous edition are: - Corrections in Table A.15 and Table A.16; - Expired patent removed and added new patents. This bilingual version (2012-07) corresponds to the monolingual English version, published in 2010-08.

IEC 61158-4-3:2019 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 fourth edition cancels and replaces the third edition published in 2014 and constitutes a technical revision. The main changes are: This edition includes the following significant technical changes with respect to the previous edition: •corrections in Table 3; •corrections in Table A.15; •spelling and grammar.