工业网络 现场总线规范 WiTSnet

[中文适用范围]： 本文件提供了自动化环境中设备与用户程序之间基本时间关键消息通信的公共元素，以及访问现场总线通信环境的手段。术语“时间关键”表示存在一个时间窗口，在该窗口内需要以一定的确定性完成一个或多个指定操作。未能在时间窗口内完成指定操作可能导致请求操作的应用程序失败，进而对设备、工厂甚至人员生命构成风险。本文件以抽象方式定义了：a) WiTSnet提供的外部可见服务，包括：1) 用于定义可通过FAL服务由用户操作的应用程序资源（对象）的抽象模型；2) 服务的原语动作和事件；3) 每个原语动作和事件相关的参数及其形式；4) 这些动作和事件之间的相互关系及其有效序列。b) WiTSnet提供的外部可见行为，包括：1) 定义数据链路层和应用层协议数据单元的抽象语法；2) 应用于数据链路层和应用层协议数据单元的编码规则传输语法；3) 定义数据链路和应用服务行为的状态机；4) 定义数据链路和应用关系状态机。本文件的目的是定义提供给以下实体的服务：c) WiTSnet现场总线应用层在应用层和数据链路层之间的边界；d) 系统管理在数据链路层和系统管理之间的边界；e) FAL用户在用户和应用层之间的边界；f) 系统管理在应用层和系统管理之间的边界。本文件旨在定义协议以：g) 定义第7章中服务原语的线表示；h) 定义与其传输相关的外部可见行为。1.2 规格：本文件的主要目标是规定适用于时间关键通信的概念性应用层服务和数据链路层服务的特性，从而补充OSI基本参考模型，指导时间关键通信的应用层协议和数据链路协议的发展。次要目标是提供从现有工业通信协议的迁移路径。本规范可用作正式应用编程接口和DL编程接口的基础。1.3 适用性：这些程序适用于支持应用层和数据链路层时间关键通信服务的系统之间的通信实例，这些系统需要能够在开放系统互连环境中互连。配置文件提供了一种简单的多属性方法来概括实现的能力及其对各种时间关键通信需求的适用性。1.4 一致性：本文件不指定个别实现或产品，也不限制工业自动化系统内应用层实体和数据链路实体的实现。本文件不包含证明符合此类要求的测试。通过实现符合本文件中定义的WiTSnet数据链路层服务和应用层服务的数据链路协议和应用层协议规范来实现一致性。 [外文原描述]： IEC PAS 63693:2026 provides the common elements for basic time-critical messaging communications between devices in an automation environment and user programs with a means to access the fieldbus communication environment. 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: a) The externally visible services provided by the WiTSnet in terms of: 1) an abstract model for defining application resources (objects) capable of being manipulated by users via the use of the FAL services; 2) the primitive actions and events of the services; 3) the parameters associated with each primitive action and event, and the form which they take; 4) the interrelationship between these actions and events, and their valid sequences. b) The externally visible behavior provided by the WiTSnet in terms of: 1) the abstract syntax defining the data-link layer and application layer protocol data units conveyed between communicating data-link and application entities; 2) the transfer syntax defining encoding rules that are applied to the data-link layer and the application layer protocol data units; 3) the data-link and the application context state machines defining the data-link and the application service behaviors visible between communicating data-link and application entities; and 4) the data-link and the application relationship state machines defining the data-link and the application service behaviors visible between communicating data-link and application entities. The purpose of this document is to define the services provided to: c) the WiTSnet fieldbus application layer at the boundary between the application and data-link layers of the Fieldbus Reference Model; d) systems management at the boundary between the data-link layer and systems management of the Fieldbus Reference Model; e) the FAL user at the boundary between the user and the application layer of the Fieldbus Reference Model, and f) systems management at the boundary between the application layer and systems management of the Fieldbus Reference Model. The purpose of this document is to define the protocol provided to: g) define the wire-representation of the service primitives defined in clause 7; and h) define the externally visible behavior associated with their transfer.