SIST EN IEC 61158-5-25:2019

SLOVENSKI STANDARD
01-november-2019
Industrijska komunikacijska omrežja - Specifikacije za procesna vodila - 5-25. del:
Definicija opravil na aplikacijski ravni - Elementi tipa 25 (IEC 61158-5-25:2019)
Industrial communication networks - Fieldbus specifications - Part 5-25: Application layer
service definition - Type 25 elements (IEC 61158-5-25:2019)
Industrielle Kommunikationsnetze - Feldbusse - Teil 5-25: Dienstfestlegungen des
Application Layer (Anwendungsschicht) - Typ 25-Elemente (IEC 61158-5-25:2019)
Réseaux de communication industriels - Spécifications des bus de terrain - Partie 5-25:
Définition des services de la couche application - Éléments de type 25 (IEC 61158-5-
25:2019)
Ta slovenski standard je istoveten z: EN IEC 61158-5-25:2019
ICS:
25.040.40 Merjenje in krmiljenje Industrial process
industrijskih postopkov measurement and control
35.100.70 Uporabniški sloj Application layer
35.110 Omreževanje Networking
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 61158-5-25

NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2019
ICS 25.040.40; 35.100.70; 35.110

English Version
Industrial communication networks - Fieldbus specifications -
Part 5-25: Application layer service definition - Type 25 elements
(IEC 61158-5-25:2019)
Réseaux de communication industriels - Spécifications des Industrielle Kommunikationsnetze - Feldbusse - Teil 5-25:
bus de terrain - Partie 5-25: Définition des services de la Dienstfestlegungen des Application Layer
couche application - Éléments de type 25 (Anwendungsschicht) - Typ 25-Elemente
(IEC 61158-5-25:2019) (IEC 61158-5-25:2019)
This European Standard was approved by CENELEC on 2019-05-23. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 61158-5-25:2019 E

European foreword
The text of document 65C/947/FDIS, future edition 1 of IEC 61158-5-25, prepared by SC 65C
"Industrial networks" of IEC/TC 65 "Industrial-process measurement, control and automation" was
submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2020-02-23
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2022-05-23
document have to be withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Endorsement notice
The text of the International Standard IEC 61158-5-25:2019 was approved by CENELEC as a
European Standard without any modification.
In the official version, for Bibliography, the following note has to be added for the standard indicated:
IEC 61158-1:2019 NOTE Harmonized as EN IEC 61158-1:2019 (not modified)

Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1  Where an International Publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 61158-3-25 2019 Industrial communication networks - EN IEC 61158-3-25 2019
Fieldbus specifications - Part 3-25: Data-
link layer service definition - Type X
elements
IEC 61158-6-25 2019 Industrial communication networks – EN IEC 61158-6-25 2019
Fieldbus specifications - Part 6-25:
Application layer protocol specification –
Type 25 elements
ISO/IEC 7498-1 -  Information technology - Open Systems - -
Interconnection - Basic reference model:
The basic model
ISO/IEC 8822 -  Information technology - Open Systems - -
Interconnection - Presentation service
definition
ISO/IEC 8824-1 -  Information technology - Abstract Syntax - -
Notation One (ASN.1): Specification of
basic notation
ISO/IEC 9545 -  Information technology - Open Systems - -
Interconnection - Application layer
structure
ISO/IEC 10731 -  Information technology - Open Systems - -
Interconnection - Basic Reference Model
- Conventions for the definition of OSI
services
IEC 61158-5-25 ®
Edition 1.0 2019-04
INTERNATIONAL
STANDARD
Industrial communication networks – Fieldbus specifications –

Part 5-25: Application layer service definition – Type 25 elements

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 25.040.40; 35.100.70; 35.110 ISBN 978-2-8322-6767-7

– 2 – IEC 61158-5-25:2019 © IEC 2019
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
1.1 Overview . 8
1.2 Specification . 9
1.3 Conformance . 9
2 Normative references . 9
3 Terms, definitions, symbols, abbreviations and conventions . 10
3.1 Referenced terms and definitions . 10
3.1.1 ISO/IEC 7498-1 terms . 10
3.1.2 ISO/IEC 8822 terms. 10
3.1.3 ISO/IEC 9545 terms. 10
3.1.4 ISO/IEC 8824-1 terms . 11
3.2 Additional Type 25 terms and definitions. 11
3.3 Symbols and abbreviations . 13
3.4 Conventions . 14
3.4.1 General conventions . 14
3.4.2 Conventions for class definitions . 14
3.4.3 Conventions for service definitions . 15
4 Concept . 16
5 Data type ASE . 17
5.1 Overview . 17
5.2 Fixed length types . 17
5.2.1 Numeric types . 17
5.3 String types . 19
5.3.1 OctetString . 19
6 Communication model specification . 19
6.1 Communication model . 19
6.1.1 General . 19
6.1.2 Cyclic communication model . 19
6.1.3 Acyclic communication model . 19
6.2 ASE type S . 20
6.2.1 Overview . 20
6.2.2 Cyclic data type S . 20
6.2.3 Acyclic data ASE type S . 25
6.3 ASE type N . 29
6.3.1 Overview type N . 29
6.3.2 Cyclic data ASE type N . 29
6.3.3 Acyclic data ASE type N . 33
6.4 AR type S . 46
6.4.1 Cyclic control type S . 47
6.4.2 Remote control . 51
6.4.3 RCL communication control . 53
6.4.4 RT communication control . 55
6.5 AR type N . 59
6.5.1 Cyclic transmission control . 59

IEC 61158-5-25:2019 © IEC 2019 – 3 –
6.5.2 Acyclic transmission control. 63
6.5.3 RT communication control type N . 68
Bibliography . 71

Figure 1 – Cyclic communication model (n:n communication with shared memory) . 19
Figure 2 – Acyclic communication model (client server model) . 20
Figure 3 – Acyclic communication model (push model) . 20
Figure 4 – Structure of ASE type S of FAL Type 25 . 20
Figure 5 – Structure of ASE type N of FAL Type 25 . 29
Figure 6 – Structure of AR type S of FAL Type 25 . 46
Figure 7 – Structure of AR type N of FAL Type 25 . 59

Table 1 – Put_cyclicdata service parameters . 22
Table 2 – Get_cyclicdata service parameters . 23
Table 3 – Ctl_cyclic service parameters . 24
Table 4 – Send_ctldata service parameters . 26
Table 5 – Send_infodata service parameters . 27
Table 6 – Send_rmtctl service parameters . 28
Table 7 – Put_cyclicdata service parameters . 30
Table 8 – Get_cyclicdata service parameters . 31
Table 9 – Control_cyclic service parameters . 33
Table 10 – Put message service parameters . 35
Table 11 – Get message service parameters . 36
Table 12 – Put inquiry message service parameters . 39
Table 13 – Put ninquiry message service parameters . 40
Table 14 – Put reply message service parameters . 41
Table 15 – Send aliveinfo service parameters . 42
Table 16 – Receive aliveinfo service parameters . 43
Table 17 – Control_acyclic service parameters . 45
Table 18 – CYC_WRITE service parameters . 48
Table 19 – CYC_READ service parameters . 49
Table 20 – CTL_CYCLIC service parameters . 50
Table 21 – SendRMTCTL service parameters . 52
Table 22 – RCL_START service parameters . 54
Table 23 – RCL_STOP service parameters . 55
Table 24 – SendCTL service parameters . 56
Table 25 – SendINFO service parameters . 57
Table 26 – SendCTL_RMT service parameters . 58
Table 27 – SendCYC service parameters . 58
Table 28 – Write_cyclicdata service parameters . 60
Table 29 – Ctl_cyclic service parameters . 61
Table 30 – Transmit_acyclicdata1 service parameters . 64
Table 31 – Transmit_acyclicdata2 service parameters . 66

– 4 – IEC 61158-5-25:2019 © IEC 2019
Table 32 – Ctl_acyclic service parameters . 67
Table 33 – Send_cyclicdata service parameters . 69
Table 34 – Send_acyclicdata service parameters . 70

IEC 61158-5-25:2019 © IEC 2019 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 5-25: Application layer service definition –
Type 25 elements
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization
comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to
promote international co-operation on all questions concerning standardization in the electrical and electronic
fields. To this end and in addition to other activities, IEC publishes International Standards, Technical
Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to
as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee
interested in the subject dealt with may participate in this preparatory work. International, governmental and
non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates
closely with the International Organization for Standardization (ISO) in accordance with conditions determined
by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has
representation from all interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated
in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage
or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61158-5-25 has been prepared by subcommittee 65C: Industrial
networks, of IEC technical committee 65: Industrial-process measurement, control and
automation.
The text of this International Standard is based on the following documents:
FDIS Report on voting
65C/947/FDIS 65C/950/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 6 – IEC 61158-5-25:2019 © IEC 2019
A list of all parts in the IEC 61158 series, published under the general title Industrial
communication networks – Fieldbus specifications, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

IEC 61158-5-25:2019 © IEC 2019 – 7 –
INTRODUCTION
This part of IEC 61158 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 61158-1.
The application service is provided by the application protocol making use of the services
available from the data-link or other immediately lower layer. This document defines the
application service characteristics that fieldbus applications and/or system management may
exploit.
Throughout the set of fieldbus standards, the term “service” refers to the abstract capability
provided by one layer of the OSI Basic Reference Model to the layer immediately above.
Thus, the application layer service defined in this document is a conceptual architectural
service, independent of administrative and implementation divisions.

– 8 – IEC 61158-5-25:2019 © IEC 2019
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 5-25: Application layer service definition –
Type 25 elements
1 Scope
1.1 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 International 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 25 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 document 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 document is to define the services provided to
a) the FAL user at the boundary between the user and the Application Layer of the Fieldbus
Reference Model, and
b) Systems Management at the boundary between the Application Layer and Systems
Management of the Fieldbus Reference Model.
This document specifies the structure and services of the IEC fieldbus Application Layer, in
conformance with the OSI Basic Reference Model (ISO/IEC 7498-1) and the OSI Application
Layer Structure (ISO/IEC 9545).
FAL services and protocols are provided by FAL application-entities (AE) contained within
the application processes. The FAL AE is composed of a set of object-oriented Application
Service Elements (ASEs) and a Layer Management Entity (LME) that manages the AE. The
ASEs provide communication services that operate on a set of related application process
object (APO) classes. One of the FAL ASEs is a management ASE that provides a common
set of services for the management of the instances of FAL classes.
Although these services specify, from the perspective of applications, how request and
responses are issued and delivered, they do not include a specification of what the
requesting and responding applications are to do with them. That is, the behavioral aspects
of the applications are not specified; only a definition of what requests and responses they

IEC 61158-5-25:2019 © IEC 2019 – 9 –
can send/receive is specified. This permits greater flexibility to the FAL users in
standardizing such object behavior. In addition to these services, some supporting services
are also defined in this document to provide access to the FAL to control certain aspects of
its operation.
1.2 Specification
The principal objective of this document 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, 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.
1.3 Conformance
This document does not specify individual implementations or products, nor does it 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 document.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document
(including any amendments) applies.
NOTE All parts of the IEC 61158 series, as well as IEC 61784-1 and IEC 61784-2 are maintained
simultaneously. Cross-references to these documents within the text therefore refer to the editions as dated in
this list of normative references.
IEC 61158-3-25:2019, Industrial communication networks – Fieldbus specifications –
Part 3-25: Data-link layer service definition – Type 25 elements
IEC 61158-6-25:2019, Industrial communication networks – Fieldbus specifications –
Part 6-25: Application layer protocol specification – Type 25 elements
ISO/IEC 7498-1, Information technology – Open Systems Interconnection – Basic Reference
Model: The Basic Model
ISO/IEC 8822, Information technology – Open Systems Interconnection – Presentation
service definition
ISO/IEC 9545, Information technology – Open Systems Interconnection – Application Layer
structure
– 10 – IEC 61158-5-25:2019 © IEC 2019
ISO/IEC 8824-1, Information technology – Abstract Syntax Notation One (ASN.1):
Specification of basic notation
ISO/IEC 10731, Information technology – Open Systems Interconnection – Basic Reference
Model – Conventions for the definition of OSI services
3 Terms, definitions, symbols, abbreviations and conventions
For the purposes of this document, the following terms, definitions, symbols, abbreviations
and conventions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1 Referenced terms and definitions
3.1.1 ISO/IEC 7498-1 terms
For the purposes of this document, the following terms given in ISO/IEC 7498-1 apply:
a) application entity;
b) application process;
c) application protocol data unit;
d) application service element;
e) application entity invocation;
f) application process invocation;
g) application transaction;
h) real open system;
i) transfer syntax.
3.1.2 ISO/IEC 8822 terms
For the purposes of this document, the following terms given in ISO/IEC 8822 apply:
a) abstract syntax;
b) presentation context.
3.1.3 ISO/IEC 9545 terms
For the purposes of this document, the following terms given in ISO/IEC 9545 apply:
a) application-association;
b) application-context;
c) application context name;
d) application-entity-invocation;
e) application-entity-type;
f) application-process-invocation;
g) application-process-type;
h) application-service-element;
i) application control service element.

IEC 61158-5-25:2019 © IEC 2019 – 11 –
3.1.4 ISO/IEC 8824-1 terms
For the purposes of this document, the following terms given in ISO/IEC 8824-1 apply:
a) object identifier;
b) type.
3.2 Additional Type 25 terms and definitions
3.2.1
ADP message
message conveyed by an autonomous decentralized system protocol
3.2.2
alive-message
message reporting own node state, periodically transmitted
3.2.3
block
basic unit of data transferred in a cyclic communication, each having a size of 64 bytes
3.2.4
category N_f
category of an autonomous decentralized system protocol in type N with a full specification
3.2.5
category N_l
category of an autonomous decentralized system protocol in type N with a light weight
specifications
3.2.6
control communication
acyclic data communication for high time-critical applications in type S network
3.2.7
cyclic communication
periodic data communication for real-time communication
3.2.8
cyclic transfer memory
memory which is allocated to each node in the data field, which each node transmits
periodically for the purpose of logical sharing of this memory area
3.2.9
data field
logical place through which specific data passes, corresponding to real networks
3.2.10
domain
administrative set consisting of multiple data fields
3.2.11
duplex LAN
two different network-paths between end nodes
3.2.12
equipment
physical hardware connected to the network

– 12 – IEC 61158-5-25:2019 © IEC 2019
EXAMPLE Station, device, and server.
3.2.13
information communication
acyclic data communication for low time-critical application in type S network
3.2.14
logical node, node
equipment in data fields where an autonomous decentralized system's function is installed
3.2.15
message mode
identifier that indicates the uses of a message
EXAMPLE Online message or a test message.
3.2.16
multicast group
group of nodes belonging to a data field to determine whether to receive the same data from
another node
3.2.17
node list
bit array structure of specifying a node to receive a request data
3.2.18
node mode
identifier that indicates the usage of a node
EXAMPLE Online node or a test node.
3.2.19
primary local area network
local area network (LAN) used in normal state in a duplex LAN system
3.2.20
priority control
transmission order control for the packets arrived from networks, according to the virtual
local area network (VLAN)
3.2.21
ring control communication
control for the type S ring network using ring control (RCL) frames
3.2.22
remote control
control for other nodes connected to a network
3.2.23
secondary local area network
local area network (LAN) for backup of a primary LAN in a duplex LAN system
3.2.24
transaction code
information to identify the characteristics of the message within a protocol data unit

IEC 61158-5-25:2019 © IEC 2019 – 13 –
3.3 Symbols and abbreviations
ADP Autonomous Decentralized Protocol
ADS-net Autonomous Decentralized System - network
AE Application Entity
AL Application Layer
AP Application Process
APDU Application Protocol Data Unit
APO Application Process Object
AR Application Relationship
AREP Application Relationship Endpoint
ASCII American Standard Code for Information Interchange
ASE Application Service Element
ASN.1 Abstract Syntax Notation 1
CRC Cyclic Redundancy Check
DF Data Field
DFN Data Field Number
DLL Data-link Layer
DMN DoMain Number
DMPM DLL Mapping Protocol Machine
FAL Fieldbus Application Layer
FSPM FAL Service Protocol Machine
GMT Greenwich Mean Time
IP Internet Protocol
IPv4 Internet Protocol version 4
IPv6 Internet Protocol version 6
LAN Local area network
LCA  Loop condition alert (type S frame type)
LCC Loop condition check (type S frame type)
LCN Loop condition notify (type S frame type)
LLD Logical link down
LLU Logical link up
LNA Loop notify answer (type S frame type)
LNN Logical Node Number
LSB Least Significant Bit
MGN Multicast Group Number
MSB Most Significant Bit
MTU Maximum Transmission Unit
OSI Open Systems Interconnection
PDU Protocol Data Unit
PLD Physical link down
QoS  Quality-of-service
RCL Ring control
RHE Rapid hello (type S frame type)
RT Real time
SCR Station condition report (type S frame type)
TCD Transaction CoDe
TMID Transfer Memory Identifier

– 14 – IEC 61158-5-25:2019 © IEC 2019
UDP User Datagram protocol
VLAN Virtual local area network
3.4 Conventions
3.4.1 General conventions
Conventions given in IEC 61158-3-25 are also applied in this document.
3.4.2 Conventions for class definitions
Class definitions are defined using templates. Each template consists of a list of attributes
and services for the class. The general form of the template is shown below:
FAL ASE:  ASE Name
CLASS:  Class Name
CLASS ID:  #
PARENT CLASS:  Parent Class Name
ATTRIBUTES:
1 (o) Key Attribute: numeric identifier
2 (o) Key Attribute: name
3 (m) Attribute: attribute name (values)
4 (m) Attribute: attribute name (values)
4.1 (s) Attribute: attribute name (values)
4.2 (s) Attribute: attribute name (values)
4.3 (s) Attribute: attribute name (values)
5 (c) Constraint: constraint expression
5.1 (m) Attribute: attribute name (values)
5.2 (o) Attribute: attribute name (values)
6 (m) Attribute: attribute name (values)
6.1 (s) Attribute: attribute name (values)
6.2 (s) Attribute: attribute name (values)
SERVICES:
1 (o) OpsService: service name
2 (c) Constraint: constraint expression
2.1 (o) OpsService: service name
3 (m) MgtService: service name

a) The "FAL ASE:" entry is the name of the FAL ASE that provides the services for the
class being specified.
b) The "CLASS:" entry is the name of the class being specified. All objects defined using
this template will be an instance of this class. The class may be specified by this
document, or by a user of this document.
c) The "CLASS ID:" entry is a number that identifies the class being specified. This number
is unique within the FAL ASE that will provide the services for this class. When qualified
by the identity of its FAL ASE, it unambiguously identifies the class within the scope of
the FAL. The value "NULL" indicates that the class cannot be instantiated. Class IDs
between 1 and 255 are reserved by this document to identify standardized classes. They
have been assigned to maintain compatibility with existing national standards. CLASS
IDs between 256 and 2048 are allocated for identifying user defined classes.
d) The "PARENT CLASS:" entry is the name of the parent class for the class being

IEC 61158-5-25:2019 © IEC 2019 – 15 –
specified. All attributes defined for the parent class and inherited by it are inherited for
the class being defined, and therefore do not have to be redefined in the template for this
class.
NOTE The parent-class "TOP" indicates that the class being defined is an initial class definition. The parent
class TOP is used as a starting point from which all other classes are defined. The use of TOP is reserved for
classes defined by this document.
e) The "ATTRIBUTES" label indicate that the following entries are attributes defined for the
class.
1) Each of the attribute entries contains a line number in column 1, a mandatory (m) /
optional (o) / conditional (c) / selector (s) indicator in column 2, an attribute type label
in column 3, a name or a conditional expression in column 4, and optionally a list of
enumerated values in column 5. In the column following the list of values, the default
value for the attribute may be specified.
2) Objects are normally identified by a numeric identifier or by an object name, or by
both. In the class templates, these key attributes are defined under the key attribute.
3) The line number defines the sequence and the level of nesting of the line. Each
nesting level is identified by a period. Nesting is used to specify
i) fields of a structured attribute (4.1, 4.2, 4.3),
ii) attributes conditional on a constraint statement (5). Attributes may be mandatory
(5.1) or optional (5.2) if the constraint is true. Not all optional attributes require
constraint statements as does the attribute defined in (5.2),
iii) the selection fields of a choice type attribute (6.1 and 6.2).
f) The "SERVICES" label indicates that the following entries are services defined for the
class.
1) An (m) in column 2 indicates that the service is mandatory for the class, while an (o)
indicates that it is optional. A (c) in this column indicates that the service is
conditional. When all services defined for a class are defined as optional, at least one
has to be selected when an instance of the class is defined.
2) The label "OpsService" designates an operational service (1).
3) The label "MgtService" designates a management service (2).
4) The line number defines the sequence and the level of nesting of the line. Each
nesting level is identified by a period. Nesting within the list of services is used to
specify services conditional on a constraint statement.
Subclause 3.4.3 represents additions in the context of their respective IEC document
standards.
3.4.3 Conventions for service definitions
3.4.3.1 General
The service model, service primitives, and time-sequence diagrams used are entirely
abstract descriptions; they do not represent a specification for implementation.
3.4.3.2 Service parameters
Service primitives are used to represent service user/service provider interactions (see
ISO/IEC 10731). They convey parameters which indicate information available in the
user/provider interaction. In any particular interface, not all parameters need be stated
explicitly.
The service specifications of this document use a tabular format to describe the component
parameters of the ASE service primitives. The parameters which apply to each group of
service primitives are set out in tables. Each table consists of up to five columns for the

– 16 – IEC 61158-5-25:2019 © IEC 2019
a) parameter name,
b) request primitive, (transmitted from the sender),
c) indication primitive, (transmitted to the receiver),
d) response primitive, (transmitted from the receiver), and
e) confirm primitive (transmitted to the sender).
One parameter or component of it is listed in each row of each table. Under the appropriate
service primitive columns, a code is used to specify the type of usage of the parameter on
the primitive specified in the column:
M parameter is mandatory for the primitive
U parameter is a User option, and may or may not be provided depending on
dynamic usage of the service user. When not provided, a default value for the
parameter is assumed.
C parameter is conditional upon other parameters or upon the environment of the
service user.
— (blank) parameter is never present.
S parameter is a selected item.
Some entries are further qualified by items in brackets. These may be
1) a parameter-specific constraint
(=) indicates that the parameter is semantically equivalent to the parameter in the
service primitive to its immediate left in the table;
2) an indication that some note applies to the entry
(n) indicates that the following note n contains additional information pertaining to
the parameter and its use.
3.4.3.3 Service procedure
The procedures are defined in terms of:
• the interactions between application entities through the exchange of fieldbus Application
Protocol Data Units, and
• the interactions between an application layer service provider and an application layer
service user in the same system through the invocation of application layer service
primitives.
These procedures are applicable to instances of communication between systems which
support time-constrained communications services within the fieldbus application layer.
4 Concept
The basic concept of application layer services follows Clause 9 of IEC 61158-1.
The FAL defined herein has two primary deployment models. Type S network ha
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