IEC 61158-5-27:2023为自动化环境中的应用程序和27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”用于表示时间窗口的存在，在该时间窗口内，需要以一定的确定性水平完成一个或多个指定的操作。未能在时间窗口内完成指定的操作有可能导致请求操作的应用程序失败，并对设备、工厂和可能的人员生命造成相应风险。

IEC 61158-5-27:2023 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 27 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.