IEC 61158-5-13:2014 defines the services provided to the FAL user at the boundary between the user and the application layer of the fieldbus reference model, and Systems Management at the boundary between the application layer and Systems Management of the fieldbus reference model. This standard specifies the structure and services of the IEC fieldbus application layer, in conformance with the OSI Basic Reference Model (ISO/IEC 7498-1) and the OSI application layer structure (ISO/IEC 9545). This second edition cancels and replaces the first edition published in 2007 and constitutes a technical revision. The main changes are: addition of synchronization feature, corrections, and editorial improvements.