现场总线应用层（FAL）为用户程序提供访问现场总线通信环境的方法。在这方面，FAL可以被视为“相应应用程序之间的窗口” IEC 61158的这一部分为自动化环境中的应用程序和12型现场总线专用材料之间的基本时间关键和非时间关键消息通信提供了通用元素。术语“时间关键型”用于表示存在一个时间窗口，在该时间窗口内，一个或多个指定动作需要以某种确定的水平完成。如果未能在时间窗口内完成指定的操作，则可能会导致请求操作的应用程序失败，并对设备、工厂以及可能的人身安全造成风险。 交叉引用:IEEE 802.1ISO/IEC 9545ISO/IEC 7498-3ISO/IEC 10646ISO/IEC/IEEE 60559ISO/IEC 7498-1ISO/IEC/IEEE 8802-3IETF RFC 791ISO/IEC 646:1991IEC 61131-3IEEE Std 802.1ISO/IEC 10731IEC 61158-1:2019 IEC 61158-3-12:2019BS ISO/IEC 646:1991EN 50325-4IEEE Std 802.1QIEC 611784-2IEC 61158-4-12IEC 61158-1EC 61158-2REPEC 6115-2014所有现行修订版购买本文件时提供的信息包括在内。

The fieldbus Application Layer (FAL) provides user programs with a means to access the fieldbus communication environment. In this respect, the FAL can be viewed as a "window between corresponding application programs." This part of IEC 61158 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 12 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.Cross References:IEEE 802.1DISO/IEC 9545ISO/IEC 7498-3ISO/IEC 10646ISO/IEC/IEEE 60559ISO/IEC 7498-1ISO/IEC/IEEE 8802-3IETF RFC 791ISO/IEC 646:1991IEC 61131-3IEEE Std 802.1DISO/IEC 10731IEC 61158-1:2019IEC 61158-3-12:2019BS ISO/IEC 646:1991EN 50325-4IEEE Std 802.1QIEC 61784-2IEC 61158-4-12IEC 61158-6-12IEC 61784-1IEC 61158-2Replaces BS EN 61158-5-12:2014 which remains currentAll current amendments available at time of purchase are included with the purchase of this document.