DIN EN 61158-5-17-2008 工业通讯网络.现场总线规范.第5-17部分:应用层设备定义.17型元件.仅为CD-ROM
Industrial communication networks - Fieldbus specifications - Part 5-17: Application layer service definition - Type 17 elements (IEC 61158-5-17:2007); English version EN 61158-5-17:2008, only on CD-ROM
This standard 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 17 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.
This standard defines in an abstract way the externally visible service provided by the different
Types of the fieldbus Application Layer in terms of
a) an abstract model for defining application resources (objects) capable of being manipulated 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 they take;
and
d) the interrelationship between these actions and events, and their valid sequences.
The purpose of this standard is to define the services provided to
1) the FAL user at the boundary between the user and the Application Layer of the Fieldbus
Reference Model, and
2) Systems Management at the boundary between the Application Layer and Systems Management
of the Fieldbus Reference Model.
This standard 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).
The principal objective of this standard is to specify 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 which gives rise to the diversity of services
standardized as the various types of IEC 61158.
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 to address
implementation issues not covered by this specification, including
a) the sizes and octet ordering of various multi-octet service parameters, and
b) the correlation of paired request and confirm, or indication and response, primitives.