標準號：BS EN 61158-5-8-2008
中文標準名稱：工業通信網絡.數據總線規范.應用層設備定義.8型元件
英文標準名稱：Industrial communication networks - Fieldbus specifications - Application layer service definition - Type 8 elements
標準類型：M11
發布日期：2008/6/30 12:00:00
實施日期：2008/6/30 12:00:00
中國標準分類號：M11
引用標準：IEC 60559;ISO/IEC 646;ISO/IEC 7498-1;ISO/IEC 7498-3;ISO/IEC 8822;ISO/IEC 8824;ISO/IEC 9545;ISO/IEC 10731
適用范圍：This standard provides common elements for basic time-critical and non-time-criticalmessaging communications between application programs in an automation environment andmaterial specific to Type 8 fieldbus. The term “time-critical” is used to represent the presenceof a time-window, within which one or more specified actions are required to be completedwith some defined level of certainty. Failure to complete specified actions within the timewindow risks failure of the applications requesting the actions, with attendant risk toequipment, plant and possibly human life.This standard defines in an abstract way the externally visible service provided by the Type 8fieldbus application layer in terms ofa) an abstract model for defining application resources (objects) capable of beingmanipulated by users via the use of the FAL service,b) the primitive actions and events of the service;c) the parameters associated with each primitive action and event, and the form which theytake; andd) the interrelationship between these actions and events, and their valid sequences.The purpose of this standard is to define the services provided to1) the FAL user at the boundary between the user and the application layer of the fieldbusreference model, and2) Systems Management at the boundary between the application layer and SystemsManagement of the fieldbus reference model.This standard specifies the structure and services of the Type 8 fieldbus application layer, inconformance with the OSI Basic Reference Model (ISO/IEC 7498) and the OSI applicationlayer structure (ISO/IEC 9545).The principal objective of this standard is to specify the characteristics of conceptualapplication layer services suitable for time-critical communications, and thus supplement theOSI Basic Reference Model in guiding the development of application layer protocols for timecriticalcommunications.A secondary objective is to provide migration paths from previously-existing industrialcommunications protocols. It is this latter objective which gives rise to the diversity of servicesstandardized as the various Types of IEC 61158, and the corresponding protocolsstandardized in subparts of IEC 61158-6.This specification may be used as the basis for formal application programming interfaces.Nevertheless, it is not a formal programming interface, and any such interface will need toaddress implementation issues not covered by this specification, includinga) the sizes and octet ordering of various multi-octet service parameters, andb) the correlation of paired request and confirm, or indication and response, primitives.