IEC 61158-5-2:2019

IEC 61158-5-2 ®
Edition 4.0 2019-04
INTERNATIONAL
STANDARD
colour
inside
Industrial communication networks – Fieldbus specifications –
Part 5-2: Application layer service definition – Type 2 elements

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IEC 61158-5-2 ®
Edition 4.0 2019-04
INTERNATIONAL
STANDARD
colour
inside
Industrial communication networks – Fieldbus specifications –

Part 5-2: Application layer service definition – Type 2 elements

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 25.040.40; 35.100.70; 35.110 ISBN 978-2-8322-6738-7

– 2 – IEC 61158-5-2:2019 © IEC 2019
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 . 12
3.1 ISO/IEC 7498-1 terms . 12
3.2 ISO/IEC 8822 terms . 13
3.3 ISO/IEC 9545 terms . 13
3.4 ISO/IEC 8824-1 terms . 13
3.5 Type 2 fieldbus data-link layer terms . 13
3.6 Type 2 fieldbus application-layer specific definitions . 13
3.7 Type 2 abbreviated terms and symbols . 21
3.8 Conventions . 22
3.8.1 Overview . 22
3.8.2 General conventions . 23
3.8.3 Conventions for class definitions . 23
3.8.4 Conventions for service definitions . 24
4 Common concepts . 25
5 Data type ASE . 25
5.1 General . 25
5.2 Formal definition of data type objects . 25
5.3 FAL defined data types . 26
5.3.1 Fixed length types . 26
5.3.2 String types . 31
5.3.3 Structure types . 32
5.4 Data type ASE service specification . 36
6 Communication model specification . 36
6.1 Concepts . 36
6.1.1 General . 36
6.1.2 General concepts . 36
6.1.3 Relationships between ASEs . 37
6.1.4 Naming and addressing . 38
6.1.5 Data types . 39
6.2 ASEs . 46
6.2.1 Object management ASE . 46
6.2.2 Connection manager ASE . 154
6.2.3 Connection ASE . 172
6.3 ARs . 186
6.3.1 Overview . 186
6.3.2 UCMM AR formal model . 197
6.3.3 Transport AR formal model . 199
6.3.4 AR ASE services . 209
6.4 Summary of FAL classes . 217

6.5 Permitted FAL services by AR type . 218
Bibliography . 220

Figure 1 – Overview of ASEs and object classes . 38
Figure 2 – Addressing format using MAC, class, instance and attribute IDs . 39
Figure 3 – Identity object state transition diagram . 60
Figure 4 – Explicit and Implicit Setting interaction . 63
Figure 5 – Static Assembly state transition diagram . 67
Figure 6 – Dynamic Assembly state transition diagram . 68
Figure 7 – Typical timing relationships for acknowledged data production . 79
Figure 8 – Example of a COS system with two acking devices . 80
Figure 9 – Message flow in COS connection – one Connection object, one consumer . 80
Figure 10 – Message flow in COS connection – multiple consumers . 81
Figure 11 – Path Reconfiguration in a ring topology . 93
Figure 12 – CPF2 time synchronization offset clock model . 94
Figure 13 – CPF2 time synchronization system with offset clock model . 95
Figure 14 – CPF2 time synchronization group startup sequence . 97
Figure 15 – Parameter object state transition diagram . 104
Figure 16 – Example of Find_Next_Object_Instance service . 130
Figure 17 – Transmission Trigger Timer behavior . 180
Figure 18 – Inactivity watchdog timer . 181
Figure 19 – Using tools for configuration . 181
Figure 20 – Production Inhibit Timer behavior . 182
Figure 21 – Context of transport services within the connection model . 189
Figure 22 – Application–to–application view of data transfer . 189
Figure 23 – Data flow diagram for a link producer . 190
Figure 24 – Data flow diagram for a link consumer . 191
Figure 25 – Triggers . 192
Figure 26 – Binding transport instances to the producer and consumer of a transport
connection that does not have a reverse data path . 193
Figure 27 – Binding transport instances to the producers and consumers of a transport
connection that does have a reverse data path . 193
Figure 28 – Binding transport instances to the producer and consumers of a multipoint
connection when the transport connection does not have a reverse data path . 194
Figure 29 – Binding transport instances to the producers and consumers of a
multipoint connection when the transport connection does have reverse data paths . 194

Table 1 – Valid IANA MIB printer codes for character set selection . 35
Table 2 – Common elements . 41
Table 3 – ST language elements . 42
Table 4 – Type conversion operations. 43
Table 5 – Values of implementation-dependent parameters . 45
Table 6 – Extensions to IEC 61131-3:2003 . 45
Table 7 – Identity object state event matrix . 61

– 4 – IEC 61158-5-2:2019 © IEC 2019
Table 8 – Static Assembly state event matrix . 67
Table 9 – Static Assembly instance attribute access . 68
Table 10 – Dynamic Assembly state event matrix . 69
Table 11 – Dynamic Assembly instance attribute access. 69
Table 12 – Message Router object Forward_Open parameters . 72
Table 13 – Acknowledge Handler object state event matrix . 76
Table 14 – Producing I/O application object state event matrix . 77
Table 15 – PTPEnable attribute default values . 84
Table 16 – Profile identification . 90
Table 17 – Profile default settings and ranges . 91
Table 18 – Profile transports . 91
Table 19 – Default PTP clock settings . 92
Table 20 – Hand_Set clock quality management . 92
Table 21 – Path Reconfiguration Signalling message . 93
Table 22 – Parameter object state event matrix . 104
Table 23 – Status codes . 107
Table 24 – Get_Attributes_All service parameters . 109
Table 25 – Set_Attributes_All service parameters . 111
Table 26 – Get_Attribute_List service parameters . 113
Table 27 – Set_Attribute_List service parameters . 115
Table 28 – Reset service parameters . 117
Table 29 – Start service parameters . 119
Table 30 – Stop service parameters . 120
Table 31 – Create service parameters . 122
Table 32 – Delete service parameters . 124
Table 33 – Get_Attribute_Single service parameters . 125
Table 34 – Set_Attribute_Single service parameters . 127
Table 35 – Find_Next_Object_Instance service parameters . 129
Table 36 – NOP service parameters . 131
Table 37 – Apply_Attributes service parameters . 132
Table 38 – Save service parameters . 134
Table 39 – Restore service parameters . 135
Table 40 – Get_Member service parameters . 137
Table 41 – Set_Member service parameters . 139
Table 42 – Insert_Member service parameters. 141
Table 43 – Remove_Member service parameters . 143
Table 44 – Group_Sync service parameters . 144
Table 45 – Add_AckData_Path service parameters . 146
Table 46 – Remove_AckData_Path service parameters . 147
Table 47 – Get_Enum_String service parameters . 148
Table 48 – Symbolic_Translation service parameters . 150
Table 49 – Flash_LEDs service parameters . 151
Table 50 – Multiple_Service_Packet service parameters . 153

Table 51 – CM_Open service parameters . 163
Table 52 – CM_Close service parameters . 165
Table 53 – CM_ Unconnected_Send service parameters . 167
Table 54 – CM_Get_Connection_Data service parameters . 168
Table 55 – CM_Search_Connection_Data service parameters . 170
Table 56 – CM_Get_Connection_Data service parameters . 171
Table 57 – I/O Connection object attribute access . 176
Table 58 – Bridged Connection object attribute access . 177
Table 59 – Explicit messaging object attribute access . 178
Table 60 – Connection_Bind service parameters . 184
Table 61 – Service_Name service parameters . 185
Table 62 – How production trigger, transport class, and CM_RPI determine when data
is produced . 188
Table 63 – Transport classes . 199
Table 64 – UCMM_Create service parameters . 210
Table 65 – UCMM_Delete service parameters . 211
Table 66 – UCMM_Write service parameters . 212
Table 67 – UCMM_Abort service parameters . 213
Table 68 – TR_Write service parameters . 214
Table 69 – TR_Trigger service parameters . 215
Table 70 – TR_Packet_arrived service parameters . 215
Table 71 – TR_Ack_received service parameters . 216
Table 72 – TR_Verify service parameters . 216
Table 73 – TR_Status_updated service parameters . 217
Table 74 – FAL class summary . 218
Table 75 – FAL services by AR type . 219

– 6 – IEC 61158-5-2:2019 © IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 5-2: Application layer service definition –
Type 2 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
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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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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
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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 IEC 61784-1 and IEC 61784-2.
International Standard IEC 61158-5-2 has been prepared by subcommittee 65C: Industrial
networks, of IEC technical committee 65: Industrial-process measurement, control and
automation.
This fourth edition cancels and replaces the third edition published in 2014. This edition
constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous
edition:
• addition of a data type in 5.3.2;
• clarifications of Object management ASE in 6.2.1;
• extensions of General ASE in 6.2.1.2.1;
• extensions/clarifications of Identity ASE in 6.2.1.2.2;
• update of Message Router ASE in 6.2.1.2.4;
• extensions/clarifications of Time Sync ASE in 6.2.1.2.6;
• updates of Parameter ASE in 6.2.1.2.7;
• updates of FAL ASE service specification in 6.2.1.3;
• extensions/clarifications of Connection manager ASE in 6.2.2;
• extensions/clarifications of Connection ASE in 6.2.3;
• extensions/clarifications of Application type in 6.3.1.4.5.
• miscellaneous editorial corrections.
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 ISO/IEC Directives, Part 2.
A list of all parts of the IEC 61158 series, published 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 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.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 8 – IEC 61158-5-2:2019 © IEC 2019
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 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.

INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 5-2: Application layer service definition –
Type 2 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 2 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 International Standard defines in an abstract way the externally visible service provided
by the Type 2 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 Type 2 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 61158-5-2:2019 © IEC 2019
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.
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 the Type 2 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 61131-3:2003 , Programmable controllers – Part 3: Programming languages
IEC 61158-1:2019, Industrial communication networks – Fieldbus specifications – Part 1:
Overview and guidance for the IEC 61158 and IEC 61784 series
IEC 61158-3-2:2014, Industrial communication networks – Fieldbus specifications – Part 3-2:
Data-link layer service definition – Type 2 elements
IEC 61158-3-2:2014/AMD1:2019
IEC 61158-4-2:2019, Industrial communication networks – Fieldbus specifications – Part 4-2:
Data-link layer protocol specification – Type 2 elements
___________
A newer edition of this standard has been published, but only the cited edition applies.

IEC 61158-6-2:2019, Industrial communication networks – Fieldbus specifications – Part 6-2:
Application layer protocol specification – Type 2 elements
IEC 61588:2009, Precision clock synchronization protocol for networked measurement and
control systems
IEC 61784-3-2, Industrial communication networks – Profiles – Part 3-2: Functional safety
fieldbuses – Additional specifications for CPF 2
ISO/IEC 646, Information technology – ISO 7–bit coded character set for information
interchange
ISO/IEC 7498-1, Information technology – Open Systems Interconnection – Basic Reference
Model: The Basic Model
ISO/IEC 8859-1, Information technology – 8-bit single-byte coded graphic character sets –
Part 1: Latin alphabet No. 1
ISO/IEC 9545, Information technology – Open Systems Interconnection – Application Layer
structure
ISO/IEC 10646, Information technology – Universal Coded Character Set (UCS)
ISO/IEC 10731, Information technology – Open Systems Interconnection – Basic Reference
Model – Conventions for the definition of OSI services
ISO/IEC/IEEE 60559, Information technology – Microprocessor Systems – Floating-Point
arithmetic
ISO 639-2, Codes for the representation of names of languages – Part 2: Alpha-3 code
ISO 8859-1 :1987, Information processing – 8-bit single-byte coded graphic character sets –
Part 1: Latin alphabet No. 1
ISO 8859-2 :1987, Information processing – 8-bit single-byte coded graphic character sets –
Part 2: Latin alphabet No. 2
ISO 8859-3 :1988, Information processing – 8-bit single-byte coded graphic character sets –
Part 3: Latin alphabet No. 3
ISO 8859-4 :1988, Information processing – 8-bit single-byte coded graphic character sets –
Part 4: Latin alphabet No. 4
:1988, Information processing – 8-bit single-byte coded graphic character sets –
ISO 8859-5
Part 5: Latin/Cyrillic alphabet
___________
A newer edition of this standard has been published by ISO/IEC, but the cited edition is the one used in the
referenced IETF standards.
A newer edition of this standard has been published by ISO/IEC, but the cited edition is the one used in the
referenced IETF standards.
A newer edition of this standard has been published by ISO/IEC, but the cited edition is the one used in the
referenced IETF standards.
A newer edition of this standard has been published by ISO/IEC, but the cited edition is the one used in the
referenced IETF standards.
– 12 – IEC 61158-5-2:2019 © IEC 2019
ISO 8859-6 :1987, Information processing – 8-bit single-byte coded graphic character sets –
Part 6: Latin/Arabic alphabet
ISO 8859-7 :1987, Information processing – 8-bit single-byte coded graphic character sets –
Part 7: Latin/Greek alphabet
ISO 8859-8 :1988, Information processing – 8-bit single-byte coded graphic character sets –
Part 8: Latin/Hebrew alphabet
ISO 8859-9 :1989, Information processing – 8-bit single-byte coded graphic character sets –
Part 9: Latin alphabet No. 5
ISO 11898:1993 , Road vehicles – Interchange of digital information – Controller area
network (CAN) for high-speed communication
IETF RFC 1759, Printer MIB, available at [viewed 2018-09-04]
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 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 ISO/IEC 7498-1 terms
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
___________
A newer edition of this standard has been published by ISO/IEC, but the cited edition is the one used in the
referenced IETF standards.
A newer edition of this standard has been published by ISO/IEC, but the cited edition is the one used in the
referenced IETF standards.
A newer edition of this standard has been published by ISO/IEC, but the cited edition is the one used in the
referenced IETF standards.
A newer edition of this standard has been published by ISO/IEC, but the cited edition is the one used in the
referenced IETF standards.
A newer edition of this standard has been published by ISO/IEC, but the cited edition is the one used in the
referenced IETF standards.
A newer edition of this standard has been published, but only the cited edition applies.

3.2 ISO/IEC 8822 terms
a) abstract syntax
b) presentation context
3.3 ISO/IEC 9545 terms
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
3.4 ISO/IEC 8824-1 terms
a) object identifier
b) type
3.5 Type 2 fieldbus data-link layer terms
The following terms, defined in IEC 61158-3-2 and IEC 61158-4-2, apply.
a) DL-time
b) DL-scheduling-policy
c) DLCEP
d) DLC
e) DL-connection-oriented mode
f) DLPDU
g) DLSDU
h) DLSAP
i) fixed tag
j) generic tag
k) link
l) MAC ID
m) network address
n) node address
o) node
p) tag
q) scheduled
r) unscheduled
3.6 Type 2 fieldbus application-layer specific definitions
For the purposes of this document, the following terms and definitions apply.

– 14 – IEC 61158-5-2:2019 © IEC 2019
3.6.1
allocate
take a resource from a common area and assign that resource for the exclusive use of a
specific entity
3.6.2
application
function or data structure for which data is consumed or produced
3.6.3
application objects
multiple object classes that manage and provide a run time exchange of messages across the
network and within the network device
3.6.4
application process
part of a distributed application on a network, which is located on one device and
unambiguously addressed
3.6.5
application process object
component of an application process that is identifiable and accessible through an FAL
application relationship
3.6.6
application process object class
class of application process objects defined in terms of the set of their network-accessible
attributes and services
3.6.7
application relationship
cooperative association between two or more application-entity-invocations for the purpose of
exchange of information and coordination of their joint operation
Note 1 to entry: This relationship is activated either by the exchange of application-protocol-data-units or as a
result of preconfiguration activities.
3.6.8
application relationship application service element
application-service-element that provides the exclusive means for establishing and
terminating all application relationships
3.6.9
application relationship endpoint
context and behavior of an application relationship as seen and maintained by one of the
application processes involved in the application relationship
Note 1 to entry: Each application process involved in the application relationship maintains its own application
relationship endpoint.
3.6.10
attribute
description of an externally visible characteristic or feature of an object
Note 1 to entry: The attributes of an object contain information about variable portions of an object. Typically,
they provide status information or govern the operation of an object. Attributes may also affect the behavior of an
object. Attributes are divided into class attributes and instance attributes.

3.6.11
behavior
indication of how an object responds to particular events
3.6.12
Best Master Clock Algorithm
BMCA
algorithm performed by each node to determine the clock that will become the master clock
on a subnet and the grandmaster clock for the domain
Note 1 to entry: The algorithm primarily compares priority1, clock quality, priority2, and source identity to
determine the best master among available candidates.
3.6.13
boundary clock
clock that has multiple Precision Time Protocol (PTP) ports in a domain and maintains the
timescale used in the domain
Note 1 to entry: It may serve as the source of time, i.e., be a master clock, and may synchronize to another clock,
i.e., be a slave clock.
[SOURCE: IEC 61588:2009, 3.1.3, modified – second sentence changed to a Note]
3.6.14
class
set of objects, all of which represent the same kind of system component
Note 1 to entry: A class is a generalization of an object; a template for defining variables and methods. All objects
in a class a
...