IEC 61158-5-27:2023

IEC 61158-5-27 ®
Edition 1.0 2023-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Industrial communication networks – Fieldbus specifications –
Part 5-27: Application layer service definition – Type 27 elements

Réseaux de communication industriels – Spécifications des bus de terrain –
Partie 5-27: Définition des services de la couche application –
Éléments de type 27
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IEC 61158-5-27 ®
Edition 1.0 2023-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Industrial communication networks – Fieldbus specifications –

Part 5-27: Application layer service definition – Type 27 elements

Réseaux de communication industriels – Spécifications des bus de terrain –

Partie 5-27: Définition des services de la couche application –

Éléments de type 27
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 25.040 ISBN 978-2-8322-6582-6

– 2 – IEC 61158-5-27:2023 © IEC 2023
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
1.1 General . 9
1.2 Specifications . 10
1.3 Conformance . 10
2 Normative references . 10
3 Terms, definitions, symbols, abbreviated terms and conventions . 11
3.1 Referenced terms and definitions . 11
3.1.1 ISO/IEC 7498-1 terms . 11
3.1.2 ISO/IEC 9545 terms . 11
3.1.3 ISO/IEC 8824-1 terms . 11
3.1.4 Terms and definitions from ISO/IEC 10731 . 12
3.2 Additional terms and definitions . 12
3.3 Abbreviations and symbols . 17
3.4 Conventions . 18
3.4.1 Overview . 18
3.4.2 Conventions for class definitions . 19
3.4.3 Conventions for service definitions . 20
4 Concepts . 21
4.1 Common concepts . 21
4.2 Type specific concepts . 21
4.2.1 General . 21
4.2.2 Node type . 21
4.2.3 Basic system configuration . 22
4.2.4 Communication sequence overview . 22
4.2.5 Network initialization . 24
4.2.6 Multi control domain system . 24
4.2.7 Multiple transmission cycles . 24
4.2.8 Sync master switching . 24
4.2.9 TSN . 24
5 Data type ASE . 24
6 Communication model specifications . 25
6.1 Type specific concepts . 25
6.2 Overview. 25
6.3 FAL ASEs . 27
6.3.1 FSM ASE . 27
6.3.2 Field Device Control ASE . 60
6.3.3 Message ASE . 89
6.3.4 Event Management ASE . 103
6.4 FAL Ars . 107
6.4.1 AR model. 107
6.4.2 FSM AREP . 111
6.4.3 FDC AREP . 121
6.4.4 MSG AREP . 133
Bibliography . 140

Figure 1 – Transmission cycle with concurrent I/O data exchange . 22
Figure 2 – Transmission cycle with sequential I/O data exchange . 23
Figure 3 – Control domain transmission band . 23
Figure 4 – FAL ASE model of Type 27 . 27
Figure 5 – CDO (Communication Data Object) . 30
Figure 6 – AR model for field device control service . 110
Figure 7 – AR model for message service . 110
Figure 8 – MSG ARs between each APs . 111

Table 1 – AP type definition . 26
Table 2 – Support list of service for each class of FSM ASE . 29
Table 3 – Overall structure of CDO . 31
Table 4 – Node object categories . 31
Table 5 – Module object category . 31
Table 6 – List of node objects (object information) . 32
Table 7 – List of node objects (object status) . 33
Table 8 – List of node objects (control) . 34
Table 9 – List of node objects (configuration) . 34
Table 10 – List of module objects (configuration) . 41
Table 11 – FSM-Reset . 43
Table 12 – FSM-GetStatus . 43
Table 13 – FSM-SetContext . 44
Table 14 – FSM-GetContext . 45
Table 15 – FSM-GetTopology . 46
Table 16 – FSM-InformTopology . 47
Table 17 – FSM-ChangeAddress . 48
Table 18 – FSM-Start . 49
Table 19 – FSMUL-RESET . 51
Table 20 – FSMUL-SET-VALUE . 51
Table 21 – FSMUL-GET-VALUE . 52
Table 22 – FSMUL-START-NET . 53
Table 23 – FSMUL-DETECT . 54
Table 24 – FSMUL-RECOG . 55
Table 25 – FSUMUL-SW-TRANS-MODE . 55
Table 26 – FSMUL-MEAS-DELAY . 56
Table 27 – FSMUL-SW-EVD . 57
Table 28 – FSMUL-CONFIG . 58
Table 29 – FSMUL-START-SYNC . 59
Table 30 – FSMUL-CLR-ERR. 59
Table 31 – FSMUL-EVENT . 60
Table 32 – FSMUL error event primitive and parameters . 60
Table 33 – Support list of service for each class of FDC ASE . 61

– 4 – IEC 61158-5-27:2023 © IEC 2023
Table 34 – FDC-Reset for master class. 64
Table 35 – FDC-Open for master class . 65
Table 36 – FDC-Enable for master class . 66
Table 37 – FDC-Connect for master class . 66
Table 38 – FDC-SyncSet for master class . 67
Table 39 – FDC-Disconnect for master class . 68
Table 40 – FDC-ResumeCycle for master class . 69
Table 41 – FDC-ComCycle for master class . 69
Table 42 – FDC-Command for master class . 70
Table 43 – FDC-DataExchange for master class . 71
Table 44 – FDC-Reset for slave class . 75
Table 45 – FDC-Open for slave class . 75
Table 46 – FDC-Enable for slave class . 76
Table 47 – FDC-Connect for slave class . 77
Table 48 – FDC-SyncSet for slave class . 78
Table 49 – FDC-Disconnect for slave class . 80
Table 50 – FDC-ResumeCycle for slave class . 80
Table 51 – FDC-ComCycle for slave class . 81
Table 52 – FDC-Command for slave class . 81
Table 53 – FDC-DataExchange for slave class . 83
Table 54 – CTC-WRITE-DATA . 85
Table 55 – CTC-READ-DATA . 86
Table 56 – CTC-SDA . 87
Table 57 – CTC-SDN . 88
Table 58 – CTC-EVENT . 89
Table 59 – Values of Event_ID for event service . 89
Table 60 – Support list of service for each class of Message ASE. 90
Table 61 – MSG-Reset for requester class . 91
Table 62 – MSG-Open for requester class . 92
Table 63 – MSG-Enable for requester class . 93
Table 64 – MSG-UserMessage for requester class. 93
Table 65 – MSG-OnewayMessage for requester class . 95
Table 66 – MSG-AbortTransaction for requester class . 97
Table 67 – MSG-Reset for responder class . 98
Table 68 – MSG-Open for responder class . 99
Table 69 – MSG-Enable for responder class . 99
Table 70 – MSG-UserMessage for responder class . 100
Table 71 – MSG-OnewayMessage for responder class . 102
Table 72 – MSG-AbortTransaction for responder class . 103
Table 73 – Support list of service for each class of Event Management ASE . 104
Table 74 – EVM-Reset . 105
Table 75 – EVM-Enable . 105
Table 76 – EVM-SyncEvent . 106

Table 77 – EVM-ReadNetClock . 106
Table 78 – Support list of service for each class of AR ASE . 108
Table 79 – AR-Reset for FSM AR class . 113
Table 80 – AR-Open for FSM AR class . 113
Table 81 – AR-Enable for FSM AR class . 114
Table 82 – AR-SendSync for FSM AR class . 115
Table 83 – AR-SendToken for FSM AR class . 116
Table 84 – AR-ReqSend for FSM AR class . 117
Table 85 – AR-SendDelay for FSM AR class . 118
Table 86 – AR-ReqCDO for FSM AR class . 119
Table 87 – AR-WriteCDO for FSM AR class . 120
Table 88 – AR-SendAsync for FSM AR class . 121
Table 89 – AR-Reset for FDC Master AR class . 124
Table 90 – AR-Open for FDC Master AR class . 124
Table 91 – AR-Enable for FDC Master AR class . 125
Table 92 – AR-CycleEvent for FDC Master AR class . 125
Table 93 – AR-StartComCycle for FDC Master AR class . 126
Table 94 – AR-ResetCycle for FDC Master AR class . 126
Table 95 – AR-SendCommand for FDC Master AR class . 127
Table 96 – AR-Reset for FDC Slave AR class . 130
Table 97 – AR-Open for FDC Slave AR class . 130
Table 98 – AR-Enable for FDC Slave AR class . 131
Table 99 – AR-CycleEvent for FDC Slave AR class . 131
Table 100 – AR-StartComCycle for FDC Slave AR class . 132
Table 101 – AR-ResetCycle for FDC Slave AR class . 132
Table 102 – AR-SendCommand for FDC Slave AR class . 133
Table 103 – AR-Reset for Message AR class . 135
Table 104 – AR-Open for Message AR class . 135
Table 105 – AR-Enable for Message AR class . 136
Table 106 – AR-SendMessage for Message AR class . 137
Table 107 – AR-ReceiveMessage for Message AR class . 138
Table 108 – AR-AbortMessage for Message AR class . 139

– 6 – IEC 61158-5-27:2023 © IEC 2023
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 5-27: Application layer service definition –
Type 27 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
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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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
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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.
Attention is drawn to the fact that the use of the associated protocol type is restricted by its
intellectual-property-right holders. In all cases, the commitment to limited release of intellectual-
property-rights made by the holders of those rights permits a layer protocol type to be used with
other layer protocols of the same type, or in other type combinations explicitly
authorized by its intellectual-property-right holders.
NOTE Combinations of protocol types are specified in the IEC 61784-1 series and the IEC 61784-2 series.
IEC 61158-5-27 has been prepared by subcommittee 65C: Industrial networks, of IEC technical
committee 65: Industrial-process measurement, control and automation. It is an International
Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
65C/1205/FDIS 65C/1234/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts of the IEC 61158 series, under the general title Industrial communication
networks – Fieldbus specifications, can be found on the IEC web site.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 8 – IEC 61158-5-27:2023 © IEC 2023
INTRODUCTION
This document 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 can
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.

INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 5-27: Application layer service definition –
Type 27 elements
1 Scope
1.1 General
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 part of IEC 61158 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 27 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 fieldbus Application Layer in terms of
• an abstract model for defining application resources (objects) capable of being manipulated
by users via the use of the FAL service,
• the primitive actions and events of the service,
• the parameters associated with each primitive action and event, and the form which they
take, and
• the interrelationship between these actions and events, and their valid sequences.
The purpose of this document is to define the services provided to
• the FAL user at the boundary between the user and the Application Layer of the Fieldbus
Reference Model, and
• 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 can

– 10 – IEC 61158-5-27:2023 © IEC 2023
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 Specifications
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 series.
This document can 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 document, including
• the sizes and octet ordering of various multi-octet service parameters, and
• 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 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 fulfil 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 the IEC 61784-1 series and the IEC 61784-2 series 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 61158-1:2023, Industrial communication networks – Fieldbus specifications – Part 1:
Overview and guidance for the IEC 61158 and IEC 61784 series
IEC 61158-6-27:2023, Industrial communication networks – Fieldbus specifications – Part 6-27:
Application layer protocol specification – Type 27 elements
ISO/IEC 7498-1, Information technology – Open Systems Interconnection – Basic Reference
Model – Part 1: The Basic Model
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
IEEE Std 802-2014, IEEE Standard for Local and Metropolitan Area Networks: Overview and
Architecture
IEEE Std 802.1AS, IEEE Standard for Local and Metropolitan Area Networks – Timing and
Synchronization for Time-Sensitive Applications
3 Terms, definitions, symbols, abbreviated terms and conventions
For the purposes of this document, the following terms, definitions, symbols, abbreviated terms
and conventions apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://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 as defined in ISO/IEC 7498-1 apply:
• abstract syntax;
• application-entity;
• application process;
• application protocol data unit;
• application-process-invocation;
• (N)-facility;
• (N)-function;
• correspondent-(N)-entities;
• presentation context;
• real system;
• transfer syntax.
3.1.2 ISO/IEC 9545 terms
For the purposes of this document, the following terms as defined in ISO/IEC 9545 apply:
• application-association;
• application-context;
• application-entity-invocation;
• application-entity-type;
• application-service-element.
3.1.3 ISO/IEC 8824-1 terms
For the purposes of this document, the following terms as defined in ISO/IEC 8824-1 apply:
• object identifier.
– 12 – IEC 61158-5-27:2023 © IEC 2023
3.1.4 Terms and definitions from ISO/IEC 10731
For the purposes of this document, the following terms as defined in ISO/IEC 10731 apply:
• OSI-service-primitive; primitive;
• OSI-service-provider; provider;
• OSI-service-user; user.
3.2 Additional terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.2.1
alarm
field device status to tell that the device has detected a fatal problem to be solved and cannot
continue normal working, through the field device control (FDC) service of the Type 27 fieldbus
Note 1 to entry: Any alarm statuses are latched and need some operations to be cleared.
Note 2 to entry: Alarms are classified into three groups; communication alarms, illegal-command-related ones, and
application specific ones. But concrete definitions are dependent on implementation of each field device.
3.2.2
application process object
network representation of a specific aspect of an application process (AP), which is modelled
as a network accessible object contained within an AP or within another APO
Note 1 to entry: Details are given in IEC 61158-1, 9.3.4.
3.2.3
application process context
AP context
shared knowledge or a common set of rules, governing communication of FAL application
entities (AEs) and describing the permissible collective communications behavior between the
AEs that are party to a specific set of application relationships (ARs)
Note 1 to entry: Data within AP context can be specified by the user in advance, by the option selected while the
user uses a field bus management (FSM) service to read out the facility of peer AP, by the automatic negotiation
function that the FSM system handles, etc. The method that is to be adopted depends on the specification of each
implementation.
3.2.4
application process type
AP type
description of a classification of application processes (APs) in terms of a set of capabilities for
FAL of the Type 27 fieldbus
Note 1 to entry: AP types are classified into three ones, C1 master AP, C2 master AP and slave AP, by their
application roles in the fieldbus network, see 6.2.
3.2.5
async command
type of a command application protocol data unit (APDU) of the FDC service of the Type 27
FAL, which can be issued any time after the previous transaction without consideration of
synchronization with the communication cycle
Note 1 to entry: Definitions, which command should be async one or not, are dependent on an application. They
can be provided as a registered set of commands and responses or device profiles (see IEC 61158-6-27, 4.4 and
Annex A).
3.2.6
asynchronous communication
state or a way of communication for the FDC service of the Type 27 FAL, in which a command
can be issued any time after the previous transaction without consideration of synchronization
with the communication cycle
Note 1 to entry: In this state, sync commands cannot be issued, but async commands can.
3.2.7
attribute
information or parameter contained in variable portions of an object
Note 1 to entry: Typically, they provide status information or govern the operation of an object. Attributes also affect
the behavior of an object.
3.2.8
C1 master
AP type that has master facilities for the FDC service of the Type 27 FAL, or the device
implementing that AP type
Note 1 to entry: Only one C1 master exists in a network of the Type 27 fieldbus.
3.2.9
C2 master
AP type that has only monitor facilities for the FDC service but requester facilities for message
(MSG) service of the Type 27 FAL, or the device implementing that AP type
Note 1 to entry: Less than two C2 masters can exist in a network of the Type 27 fieldbus.
3.2.10
command
PDU issued by a requester or a master to make a responder or a slave execute some functions
3.2.11
communication
process to exchange information in a formal manner between two or more devices, users, APs
or entities
3.2.12
transfer
process to convey a PDU from a sender to a receiver
3.2.13
transmission
process to send out and propagate electrical signals or encoded data
3.2.14
communication cycle
period of repetitive activities synchronized with the transmission cycle while the connection
establishing for the FDC protocol of the Type 27 FAL
Note 1 to ent
...