BS EN IEC 61158-3-25:2019

What are BS EN IEC 61158-3-25 - fieldbus type 25 about?  

BS EN IEC 61158-3-25 is part of the BS EN IEC 61158 series that has been created to facilitate the interconnection of automation system components. BS EN IEC 61158-3-25 is related to other standards in the set as defined by the “three-layer” Fieldbus reference model described in IEC 61158-1.  

BS EN IEC 61158-3-25 provides common elements for basic time-critical messaging communications between devices in an automation environment. 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 IEC 61158-3-25 defines in an abstract way the externally visible service provided by the Type 25 Fieldbus data-link layer in terms of: 

• The primitive actions and events of the service 
• The parameters associated with each primitive action and event, and the form which they take 
• The interrelationship between these actions and events, and their valid sequences 

The purpose of BS EN IEC 61158-3-25 is to define the services provided to: 

• The Type 25 Fieldbus application layer at the boundary between the application and datalink layers of the Fieldbus reference model 
• Systems management at the boundary between the data-link layer and systems management of the Fieldbus reference model 

Who is BS EN IEC 61158-3-25 - fieldbus type 25 for? 

BS EN IEC 61158-3-25 on fieldbus type 25 elements is useful for: 

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

Why should you use BS EN IEC 61158-3-25 - fieldbus type 25?  

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 data-link layer service defined in this document is a conceptual architectural service, independent of administrative and implementation divisions. 

The principal objective of BS EN IEC 61158-3-25 is to specify, and thus supplement the OSI Basic Reference Model in guiding the development of data-link protocols for time-critical communications. A secondary objective is to provide migration paths from previously-existing industrial communications protocols. This specification may be used as the basis for formal DL-Programming-Interfaces. BS EN IEC 61158-3-25 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, and 
• The correlation of paired request and confirm, or indication and response, primitives 

Using BS EN IEC 61158-3-25 guidelines you are in a position to facilitate industrial automation that accelerates productivity.