工业通信网络 现场总线规范 第5-26部分:应用层服务定义 26型元件

[中文适用范围]： 本标准适用于工业通信网络中的现场总线应用层服务定义，特别是类型26元素的应用层服务定义。它涵盖了应用层服务的基本概念、数据类型、通信模型以及相关的服务规范。本标准还定义了类型26现场总线的协议栈、通信模型、循环数据通信服务、消息数据服务、负载测量服务、网络管理服务等。 [外文原描述]： IEC 61158-5-26:2023 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 26 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 document defines in an abstract way the externally visible service provided by the Type26 fieldbus application layer in terms of: an abstract model for defining application resources (objects) capable of being manipulated by users via the use of the FAL service; the primitive actions and events of the service; the parameters associated with each primitive action and event, and the form which they take; and the interrelationship between these actions and events, and their valid sequences.