工业通信网络.现场总线规范.第6-3部分:应用层协议规范.第3类元件

[中文适用范围]： 工业通信网络 – 现场总线规范 – 第 6-3 部分：应用层协议规范 – 3 型元素。本文档规定了工业通信网络中用于现场总线的特定类型（3 型）的应用层协议规范。它定义了协议元素、数据交换、诊断、参数化、配置、全局控制、时钟同步、错误处理、上传/下载、总线参数集、从站参数集、统计计数器、地址设置、启动/中止以及读取/写入/数据传输等功能的数据单元结构和编码规则。该规范适用于基于 IEC 61158 系列的 Profibus 类型应用层实现。 [外文原描述]： IEC 61158-6-3:2019 provides common elements for basic time-critical and non-time-critical messaging communications between application programs in an automation environment and material specific to Type 2 fieldbus. The term “time-critical” is used to represent the presence of a time-window, within which one or more specified actions are required to be completed with some defined level of certainty. Failure to complete specified actions within the time window risks failure of the applications requesting the actions, with attendant risk to equipment, plant and possibly human life. This International Standard specifies interactions between remote applications and defines the externally visible behavior provided by the Type 2 fieldbus application layer. The purpose of this document is to define the protocol provided to a) define the wire-representation of the service primitives defined in this document, and b) define the externally visible behavior associated with their transfer. This document specifies the protocol of the Type 2 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 fourth edition includes the following significant technical changes with respect to the previous edition: - corrected substitutions in Table 4; - corrections in 5.3.14; - corrections in 5.5.6; - corrections in 5.17.15; - corrections in 5.17.16.2; - spelling and grammar.