IEC 61158-5-20:20 14定义了在用户和现场总线参考模型的应用层之间的边界处向FAL用户提供的服务，以及在现场总线参考模型的应用层和系统管理之间的边界处的系统管理。本标准规定了IEC现场总线应用层的结构和服务，符合OSI基本参考模型（ISO/IEC 7498-1）和OSI应用层结构（ISO/IEC 9545）。本第三版取消并取代2010年出版的第二版，构成技术修订。主要变化有: -增加了数据类型； -增加服务； -更新了规范性参考文献、术语、定义、符号、缩写； -更正编辑错误和案文。

IEC 61158-5-20:2014 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 third edition cancels and replaces the second edition published in 2010 and constitutes a technical revision. The main changes are:
- added Data types;
- added services;
- updated the Normative references, Terms, definitions, symbols, abbreviations;
- corrected the editorial errors and the text.