IEC 61158-4-24:2019 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 second edition cancels and replaces the first edition published in 2014. This edition constitutes a technical revision with the following technical changes:
°°°patent declaration in the Introduction;
°°°corrections on transmission sequence of fixed-width time slot type in 4.3.2;
°°°technical extension for band sharing between I/O data exchange and message communication;
°°°spelling and grammar