BS EN IEC 61158-5-12:2019

What is BS EN IEC 61158-5-12 – FAL type 12 application layer protocol about?  

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 IEC 61158-5-12  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. BS EN IEC 61158-5-12  defines in an abstract way the externally visible service provided by the different types of the FAL in terms of: 

• An abstract model for defining application resources (objects) capable of being manipulated by users via the use of the FAL service 
• The primitive actions and events of the service 
• The parameters associated with each primitive action and event, and the form in which they take 
• The interrelationship between these actions and events, and their valid sequences 

The purpose of BS EN IEC 61158-5-12 is to define the services provided to: 

• The FAL user at the boundary between the user and the Application Layer of the Fieldbus Reference Model 
• Systems Management at the boundary between the Application Layer and Systems Management of the Fieldbus Reference Model 

BS EN IEC 61158-5-12 specifies the structure and services of the IEC Fieldbus Application Layer, in conformance with the OSI Basic Reference Model (ISO/IEC 7498) and the OSI Application Layer Structure (ISO/IEC 9545). 

Note: BS EN IEC 61158-5-12 is not a formal programming interface, and any such interface will need to address implementation issues not covered by this specification, including 

• The sizes and octet ordering of various multi-octet service parameters 
• The correlation of paired request and confirm, or indication and response, primitives 

Who is BS EN IEC 61158-5-12 – FAL type 12 application layer protocol for? 

BS EN IEC 61158-5-12 on FAL type 12 application layer protocol is useful for: 

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

Why should you use BS EN IEC 61158-5-12 – FAL type 12 application layer protocol?  

BS EN IEC 61158-5-12 is produced to facilitate the interconnection of automation system components. It is related to other standards in the set as defined by the “three-layer” fieldbus reference model described in IEC 61158-1. The application service is provided by the application protocol making use of the services available from the data link or other immediately lower layer. BS EN IEC 61158-5-12 defines the application service characteristics that Fieldbus applications and/or system management may exploit. 

Throughout the set of Fieldbus standards, the term “service” refers to the abstract capability provided by one layer of the OSI Basic Reference Model to the layer immediately above. The application layer service defined in BS EN IEC 61158-5-12 is a conceptual architectural service, independent of administrative and implementation divisions. 

BS EN IEC 61158-5-12 specifies the characteristics of conceptual application layer services suitable for time-critical communications, and thus supplement the OSI Basic Reference Model in guiding the development of application layer protocols for time-critical communications. 

A secondary objective is to provide migration paths from previously-existing industrial communications protocols. It is this latter objective that gives rise to the diversity of services standardized as the various Types of IEC 61158, and the corresponding protocols standardized in subparts of IEC 61158-6. BS EN IEC 61158-5-12 may be used as the basis for formal Application Programming-Interfaces. Using BS EN IEC 61158-5-12 guidelines, you are in a position to facilitate industrial automation that accelerates productivity. 

What’s changed since the last update?  

BS EN IEC 61158-5-12:2019 is the fourth edition that supersedes EN IEC 61158-5-12:2019 and is identical to BS EN IEC 61158-5-12:2019, which will be withdrawn on 15 May 2022. The technical changes as compared to the third edition published in 2014 are: 

• Technical corrections 
• Editorial improvements for clarification