IEC 61158-4-2:2010

IEC 61158-4-2:2007 describes the protocol that provides communication opportunities to all participating data-link entities, sequentially and in a cyclic synchronous manner. Foreground scheduled access is available for time-critical activities together with background unscheduled access for less critical activities. This protocol optimizes each access opportunity by concatenating multiple DLSDUs and associated DLPCI into a single DLPDU, thereby improving data transfer efficiency for data-link entities that actively source multiple streams of data. This first edition and its companion parts of the IEC 61158-4 subseries cancel and replace IEC 61158-4:2003. This edition of this part constitutes a minor revision. This part and its companion Type 2 parts also cancel and replace IEC/PAS 62413, published in 2005. This edition of IEC 61158-4 includes the following changes: - 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 -4 1, -4 2, , -4-19. This bilingual version (2014-07) corresponds to the English version, published in 2007-12.

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.