IEC 61158-3-18:2007 defines in an abstract way the externally visible service provided by the Type 18 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;
- and the interrelationship between these actions and events, and their valid sequences. This first edition and its companion parts of the IEC 61158-3 subseries cancel and replace IEC 61158-3:2003. This edition of this part constitutes a technical addition. It includes the following changes:
- deletion of the former Type 6 fieldbus, and the placeholder for a Type 5 fieldbus data-link layer, for lack of market relevance;
- addition of new types of fieldbuses;
- division of this part into multiple parts numbered 3-1, 3-2,..., 3-19. This bilingual version (2013-07) corresponds to the monolingual English version, published in 2007-12.