1.1 General
This standard is one of a series produced to facilitate the interconnection of automation
system components. It is related to other standards in the set as defined by the “three-layer”
fieldbus reference model described in IEC/TR 61158-1.
This sub-part contains material specific to Type 3 fieldbus.
1.2 Overview
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 3 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.
1.3 Specifications
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 timecritical
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, and the corresponding protocols
standardized 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 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.
1.4 Conformance
This standard do not specify individual implementations or products, nor do they constrain the
implementations of application layer entities within industrial automation systems.
There is no conformance of equipment to this application layer service definition standard.
Instead, conformance is achieved through implementation of conforming application layer
protocols that fulfill any given Type of application layer services as defined in this part of IEC 61158.
IEC 61158-5-3:2007 history
2014IEC 61158-5-3:2014 Industrial communication networks - Fieldbus specifications - Part 5-3: Application layer service definition - Type 3 elements
2010IEC 61158-5-3:2010 Industrial communication networks - Fieldbus specifications - Part 5-3: Application layer service definition - Type 3 elements
2007IEC 61158-5-3:2007 Industrial communication networks - Fieldbus specifications - Part 5-3: Application layer service definition - Type 3 elements