BS EN 61158-6-18:2012

What is BS EN 61158-6-18 - Type 18 application layer protocol specification about?

BS EN 61158-6-18 is part of a series produced to facilitate the interconnection of automation system components. BS EN 61158-6-18 is related to other standards in the set as defined by the “three-layer” fieldbus reference model described in IEC/TR 61158-1.

BS EN 61158-6-18 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 18 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 61158-6-18 specifies interactions between remote applications and defines the externally visible behaviour provided by the Type 18 fieldbus application layer in terms of:

• The formal abstract syntax defining the application layer protocol data units conveyed between communicating application entities
• The transfer syntax defining encoding rules that are applied to the application layer protocol data units
• The application context state machine defining the application service behaviour visible between communicating application entities
• The application relationship state machines defining the communication behaviour visible between communicating application entities

Who is BS EN 61158-6-18 - Type 18 application layer protocol specification for?

BS EN 61158-6-18 on industrial communication networks is useful for:

• The IT industry / Software programmers 
• The automation industry
• Networking sectors
• Implementors and designers of industrial automation systems

Why should you use BS EN 61158-6-18 - Type 18 application layer protocol specification?

The application protocol provides the application service by making use of the services available from the data link or other immediately lower layer.

BS EN 61158-6-18 provide you with a set of rules for communication expressed in terms of the procedures to be carried out by peer application entities (AEs) at the time of communication.

BS EN 61158-6-18 specifies the syntax and behaviour of the application layer protocol that conveys the application layer services defined in IEC 61158-5-18.

BS EN 61158-6-18 provides migration paths from previously-existing industrial communications protocols.

Overall, by using BS EN 61158-6-18 together with other standards positioned within the OSI or fieldbus reference models, otherwise incompatible systems can work together in any combination.

What’s changed since the last update?

BS EN 61158-6-18:2012 supersedes EN 61158-6-18:2008. BS EN 61158-6-18:2012 includes the following significant technical changes with respect to EN 61158-6-18:2008:

• Editorial corrections
• Addition of cyclic data segmenting