标准摘要
[中文适用范围]： 概述 数据链路层在自动化环境中的设备之间提供基本的时间关键型消息通信。该协议向所有参与的数据链路实体提供通信机会：a）以同步启动循环方式@和b）以循环或非循环异步方式@根据每个数据链路实体的每个周期的请求。因此，该协议的特点是异步提供循环和非循环访问，但每个周期同步重新启动。适用性 这些程序适用于系统之间的通信实例，这些系统支持 OSI 参考模型@的数据链路层内的时间关键型通信服务，并且需要能够在开放系统互连环境中进行互连。 [外文原描述]： IEC 61158-4-12:2014 specifies procedures for the timely transfer of data and control information from one data-link user entity to a peer user entity, and among the data-link entities forming the distributed data-link service provider and the structure of the fieldbus DLPDUs used for the transfer of data and control information by the protocol of this standard, and their representation as physical interface data units. This third edition cancels and replaces the second edition published in 2010 and constitutes a technical revision. The main changes are: bug fixes and editorial improvements.
英文名称Industrial communication networks - Fieldbus specifications - Part 4-12: Data-link layer protocol specification - Type 12 elements