DIN EN 61158-6-4-2008 工业通信网络.现场总线规范.第6-4部分:应用层协议规范.4型元件
Industrial communication networks - Fieldbus specifications - Part 6-4: Application layer protocol specification - Type 4 elements (IEC 61158-6-4:2007); English version EN 61158-6-4:2008, 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 4 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 specifies interactions between remote applications and defines the externally visible
behavior provided by the Type 4 fieldbus application layer in terms of
a) the formal abstract syntax defining the application layer protocol data units conveyed between
communicating application entities;
b) the transfer syntax defining encoding rules that are applied to the application layer protocol data
units;
c) the application context state machine defining the application service behavior visible between
communicating application entities;
d) the application relationship state machines defining the communication behavior visible between
communicating application entities.
The purpose of this standard is to define the protocol provided to
1) define the wire-representation of the service primitives defined in IEC 61158-5-4, and
2) define the externally visible behavior associated with their transfer.
This standard specifies the protocol of the Type 4 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 syntax and behavior of the application layer
protocol that conveys the application layer services defined in IEC 61158-5-4.
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 protocols
standardized in IEC 61158-6.