BS EN 61158-6-4:2014 PDF

What is BS EN 61158-6-4 - Application layer protocol specification - Type 4 elements about?

BS EN 61158-6-4 is part of the BS EN IEC 61158 series that has been created to facilitate the interconnection of automation system components. 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.” BS EN 61158-6-4 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 4 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. BS EN 61158-6-4 defines in an abstract way the externally visible behaviour provided by the Type 4 Fieldbus application layer in terms of: