IEC 61158-6-20:2010 Industrial communication networks - Fieldbus specifications - Part 6-20: Application layer protocol specification - Type 20 elements
The Fieldbus Application Layer (FAL) provides user programs with a means to access the
fieldbus communication environment. In this respect, the FAL can be viewed as a “window
between corresponding application programs.”
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 20 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 behavior provided by the Type
20 of the fieldbus Application Layer in terms of
a) the abstract syntax defining the application layer protocol data units conveyed between
communicating application entities,
b) the transfer syntax defining the application layer protocol data units conveyed between
communicating application entities,
c) the application context state machine defining the application service behavior visible
between communicating application entities; and
d) the application relationship state machines defining the communication behavior visible
between communicating application entities; and.
The purpose of this standard is to define the protocol provided to define
a) the wire-representation of the service primitives defined in IEC 61158-5-20, and
b) the externally visible behavior associated with their transfer.
This standard specifies the protocol of the Type 20 IEC fieldbus application layer, in
conformance with the OSI Basic Reference Model (ISO/IEC 7498) and the OSI Application
Layer Structure (ISO/IEC 9545).
IEC 61158-6-20:2010 history
2014IEC 61158-6-20:2014 Industrial communication networks - Fieldbus specifications - Part 6-20: Application layer protocol specification - Type 20 elements
2010IEC 61158-6-20:2010 Industrial communication networks - Fieldbus specifications - Part 6-20: Application layer protocol specification - Type 20 elements
2007IEC 61158-6-20:2007 Industrial communication networks - Fieldbus specifications - Part 6-20: Application layer protocol specification - Type 20 elements