SIST EN 61784-3-17:2018

SLOVENSKI STANDARD
01-februar-2018
Industrijska komunikacijska omrežja - Profili - 3-17. del: Funkcijska varnost
procesnih vodil - Dodatne specifikacije za CPF 17 (IEC 61784-3-17:2016)
Industrial communication networks - Profiles - Part 3-17: Functional safety fieldbuses -
Additional specifications for CPF 17 (IEC 61784-3-17:2016)
Industrielle Kommunikationsnetze - Profile - Teil 3-17: Funktional sichere Übertragung
bei Feldbussen - Zusätzliche Festlegungen für die Kommunikationsprofilfamilie 17 (IEC
61784-3-17:2016)
Réseaux de communication industriels - Profils - Partie 3-17: Bus de terrain de sécurité
fonctionnelle - Spécifications supplémentaires pour CPF 17 (IEC 61784-3-17:2016)
Ta slovenski standard je istoveten z: EN 61784-3-17:2017
ICS:
25.040.40 Merjenje in krmiljenje Industrial process
industrijskih postopkov measurement and control
35.100.01 Medsebojno povezovanje Open systems
odprtih sistemov na splošno interconnection in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 61784-3-17

NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2017
ICS 25.040.40; 35.100.01
English Version
Industrial communication networks - Profiles - Part 3-17:
Functional safety fieldbuses - Additional specifications for CPF
(IEC 61784-3-17:2016)
Réseaux de communication industriels - Profils - Partie 3- Industrielle Kommunikationsnetze - Profile - Teil 3-17:
17: Bus de terrain de sécurité fonctionnelle - Spécifications Funktional sichere Übertragung bei Feldbussen -
supplémentaires pour CPF 17 Zusätzliche Festlegungen für die
(IEC 61784-3-17:2016) Kommunikationsprofilfamilie 17
(IEC 61784-3-17:2016)
This European Standard was approved by CENELEC on 2016-09-01. 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, 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
© 2017 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 61784-3-17:2017 E
European foreword
The text of document 65C/851/FDIS, future edition 1 of IEC 61784-3-17:2016, 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 EN 61784-3-17:2017.

The following dates are fixed:

• latest date by which this document has (dop) 2018-06-01
to be implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2020-12-01
standards conflicting with this
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 61784-3-17:2016 was approved by CENELEC as a
European Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards
indicated:
IEC 60204-1 NOTE  Harmonized as EN 60204-1
IEC 61000-6-7:2014 NOTE  Harmonized as EN 61000-6-7:2015
IEC 61131-6 NOTE  Harmonized as EN 61131-6
IEC 61158-2 NOTE  Harmonized as EN 61158-2
IEC 61496 (all parts) NOTE  Harmonized as EN 61496 (all parts)
IEC 61508-2 NOTE  Harmonized as EN 61508-2.
IEC 61508-4:2010 NOTE  Harmonized as EN 61508-4:2010 (not modified).
IEC 61508-5:2010 NOTE  Harmonized as EN 61508-5:2010 (not modified).
IEC 61511 (all parts) NOTE  Harmonized as EN 61511 (all parts)
IEC 61784-5 (all parts) NOTE  Harmonized as EN 61784-5 (all parts)
IEC 61800-5-2 NOTE  Harmonized as EN 61800-5-2
IEC 62061 NOTE  Harmonized as EN 62061
IEC 62443 (all parts) NOTE  Harmonized as prEN 62443 (all parts)
IEC/TR 62685 NOTE  Harmonized as CLC/TR 62685
ISO 10218-1 NOTE  Harmonized as EN ISO 10218-1
ISO 12100 NOTE  Harmonized as EN ISO 12100
ISO 13849 (all parts) NOTE  Harmonized as EN ISO 13849 (all parts)
ISO 13849-1:2006 NOTE  Harmonized as EN ISO 13849-1:2006
ISO 13849-2 NOTE  Harmonized as EN ISO 13849-2
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 When 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 61000-6-2 -  Electromagnetic compatibility (EMC) - Part EN 61000-6-2 -
6-2: Generic standards - Immunity
standard for industrial environments
IEC 61131-2 -  Industrial-process measurement and EN 61131-2 -
control - Programmable controllers - Part
2: Equipment requirements and tests
IEC 61158-3-21 2010 Industrial communication networks - EN 61158-3-21 2012
Fieldbus specifications - Part 3-21: Data-
link layer service definition - Type 21
elements
IEC 61158-4-21 2010 Industrial communication networks - EN 61158-4-21 2012
Fieldbus specifications -- Part 4-21: Data-
link layer protocol specification - Type 21
elements
IEC 61158-5-21 2010 Industrial communication networks - EN 61158-5-21 2012
Fieldbus specifications -- Part 5-21:
Application layer service definition - Type
21 elements
IEC 61158-6-21 2010 Industrial communication networks - EN 61158-6-21 2012
Fieldbus specifications - Part 6-21:
Application layer protocol specification -
Type 21 elements
IEC 61326-3-1 -  Electrical equipment for measurement, EN 61326-3-1 -
control and laboratory use - EMC
requirements - Part 3-1: Immunity
requirements for safety-related systems
and for equipment intended to perform
safety-related functions (functional safety)
- General industrial applications
IEC 61326-3-2 -  Electrical equipment for measurement, - -
control and laboratory use - EMC
requirements - Part 3-2: Immunity
requirements for safety-related systems
and for equipment intended to perform
safety-related functions (functional safety)
- Industrial applications with specified
electromagnetic environment
IEC 61508 series Functional safety of EN 61508 series
electrical/electronic/programmable
electronic safety-related systems -- Part 1:
General requirements
IEC 61508-1 2010 Functional safety of EN 61508-1 2010
electrical/electronic/programmable
electronic safety-related systems -- Part 1:
General requirements
IEC 61784-2 -  Industrial communication networks - EN 61784-2 -
Profiles - Part 2: Additional fieldbus profiles
for real-time networks based on ISO/IEC
8802-3
IEC 61784-3 -  Industrial communication networks - EN 61784-3 -
Profiles - Part 3: Functional safety
fieldbuses - General rules and profile
definitions
IEC 61784-5-17 2013 Industrial communication networks - EN 61784-5-17 2013
Profiles -- Part 5-17: Installation of
fieldbuses - Installation profiles for CPF 17
IEC 61918 -  Industrial communication networks - EN 61918 -
Installation of communication networks in
industrial premises
IEC 61784-3-17 ®
Edition 1.0 2016-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Industrial communication networks – Profiles –

Part 3-17: Functional safety fieldbuses – Additional specifications for CPF 17

Réseaux de communication industriels – Profils –

Partie 3-17: Bus de terrain de sécurité fonctionnelle – Spécifications

supplémentaires pour CPF 17
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 25.040.40, 35.100.05 ISBN 978-2-8322-3493-8

– 2 – IEC 61784-3-17:2016  IEC 2016
CONTENTS
FOREWORD . 5
0 Introduction . 7
0.1 General . 7
0.2 Patent declaration . 9
1 Scope . 10
2 Normative references. 10
3 Terms, definitions, symbols, abbreviated terms, and conventions . 11
3.1 Terms and definitions . 11
3.1.1 Common terms and definitions . 11
3.1.2 CPF 17: Additional terms and definitions . 17
3.2 Symbols and abbreviated terms . 17
3.2.1 Common symbols and abbreviated terms . 17
3.2.2 CPF 17: Additional symbols and abbreviated terms . 18
3.3 Conventions . 18
4 Overview of FSCP 17/1 (RAPIEnet Safety™). 18
5 General . 20
5.1 External documents providing specifications for the profile . 20
5.2 Safety functional requirements . 20
5.3 Safety measures . 20
5.3.1 General . 20
5.3.2 (Virtual) sequence number . 21
5.3.3 Time expectation with watchdog . 21
5.3.4 Connection authentication . 21
5.3.5 Feedback message . 21
5.3.6 Data integrity assurance . 21
5.4 Safety communication layer structure . 22
5.4.1 Principle of FSCP 17/1 safety communications . 22
5.4.2 CPF 17 communication structures . 22
5.5 Relationships with FAL (and DLL, PhL) . 22
5.5.1 General . 22
5.5.2 Data types . 23
6 Safety communication layer services . 23
6.1 Overview. 23
6.2 Functional Safety connection . 23
6.2.1 General . 23
6.2.2 Initiator class specification . 23
6.2.3 Responder-class specification . 24
6.2.4 Sender class specification . 25
6.2.5 Receiver class specification . 27
6.3 Functional Safety data transmission service . 29
6.4 Functional Safety connection relation . 29
7 Safety communication layer protocol . 30
7.1 Safety PDU format . 30
7.1.1 General . 30
7.1.2 FSPDU command. 31

IEC 61784-3-17:2016  IEC 2016 – 3 –
7.1.3 Authentication key . 31
7.1.4 FSPDU CRC . 31
7.2 FSCP 17/1 communication procedure . 34
7.2.1 FSCP 17/1 device states . 34
7.3 Response to communication errors . 42
7.3.1 General . 42
7.4 State table for SCL of CPF 17 . 42
7.4.1 General . 42
7.4.2 Events . 43
7.4.3 State table for Initiator . 44
7.4.4 State table for Responder. 53
8 Safety communication layer management . 62
8.1 FSCP 17/1 parameter handling . 62
8.2 Functional Safety communication parameters . 62
9 System requirements . 62
9.1 Indicators and switches . 62
9.2 Installation guidelines . 62
9.3 Safety function response time . 62
9.4 Duration of demands . 65
9.5 Constraints for calculation of system characteristics . 65
9.5.1 General . 65
9.5.2 Number of devices . 65
9.5.3 Probabilistic consideration . 65
9.6 Maintenance . 66
9.7 Safety manual . 66
10 Assessment . 66
Annex A (informative) Additional information for functional safety communication
profiles of CPF 17 . 67
A.1 Hash function calculation . 67
A.2 … . 68
Annex B (informative) Information for assessment of the functional safety
communication profiles of CPF 17 . 69
Bibliography . 70

Figure 1 – Relationships of IEC 61784-3 with other standards (machinery) . 7
Figure 2 – Relationships of IEC 61784-3 with other standards (process) . 8
Figure 3 – Communication relationships among FSCP 17 devices . 19
Figure 4 – Safety layer architecture . 22
Figure 5 – Functional Safety Cycle . 29
Figure 6 – Connection relationships among FSCP 17/1 devices . 30
Figure 7 – Functional Safety PDU for CPF 17 over type 21 PDU . 30
Figure 8 – FSPDU CRC code generation process . 32
Figure 9 – Example of sequence number changing . 33
Figure 10 – CRC comparison operation . 34
Figure 11 – FSCP 17/1 device states . 35
Figure 12 – State diagram for Functional Safety device . 43
Figure 13 – State diagram for Initiator . 44

– 4 – IEC 61784-3-17:2016  IEC 2016
Figure 14 – State diagram for Responder . 53
Figure 15 – Safety function response time . 63
Figure 16 – Residual error rate of FSCP 17/1 . 66

Table 1 – Deployed measures to manage errors . 21
Table 2 – General FSPDU . 31
Table 3 – FSPDU command . 31
Table 4 – FSPDU with 4 octets of safety data and RESET command after restart (reset
connection) or error . 36
Table 5 – FSPDU with 4 octets of safety data and RESET command to acknowledge a
reset command from the Initiator . 36
Table 6 – Connection request PDU for the Initiator in CONNECTION state . 37
Table 7 – Connection response PDU for the Responder in CONNECTION state . 37
Table 8 – Safety data transferred in the SET_PARA state . 38
Table 9 – Sending FSPDU with 6 octets of safety data from the Initiator in SET_PARA
state . 38
Table 10 – Expected FSPDU with 6 octets of safety data from the Responder in
SET_PARA state . 39
Table 11 – Safety data from the Initiator in the WAIT_PARA state . 39
Table 12 – Sending FSPDU with 6 octets of safety data from the Initiator in the
WAIT_PARA state . 40
Table 13 – Receiving FSPDU with 6 octets of safety data from the Responder in the
WAIT_PARA state . 40
Table 14 – FSPDU of Safety data in the DATA state . 41
Table 15 – Example of 4 octets of safety data from a Sender . 41
Table 16 – Example of ACK PDU from the Receiver with 4 octets of safety data . 41
Table 17 – Functional Safety communication errors . 42
Table 18 – Functional Safety communication error codes . 42
Table 19 – States of the Functional Safety Initiator . 43
Table 20 – States of the Functional Safety Responder . 43
Table 21 – Events in the Functional Safety state . 44
Table 22 – Functional Safety communication parameters . 62
Table A.1 – the lookup table for FSCP 17/1 . 68

IEC 61784-3-17:2016  IEC 2016 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL COMMUNICATION NETWORKS –
PROFILES –
Part 3-17: Functional safety fieldbuses –
Additional specifications for CPF 17

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.
International Standard IEC 61784-3-17 has been prepared by subcommittee 65C: Industrial
networks, of IEC technical committee 65: Industrial-process measurement, control and
automation.
The text of this standard is based on the following documents:
FDIS Report on voting
65C/851/FDIS 65C/854/RVD
Full information on the voting for the approval of this 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 61784-3-17:2016  IEC 2016
A list of all parts of the IEC 61784-3 series, published under the general title Industrial
communication networks – Profiles – Functional safety fieldbuses, 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.
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.
IEC 61784-3-17:2016  IEC 2016 – 7 –
0 Introduction
0.1 General
The IEC 61158 fieldbus standard together with its companion standards IEC 61784-1 and
IEC 61784-2 defines a set of communication protocols that enable distributed control of
automation applications. Fieldbus technology is now considered well accepted and well
proven. Thus fieldbus enhancements continue to emerge, addressing applications for areas
such as real time, safety-related and security-related applications.
This standard explains the relevant principles for functional safety communications with
reference to IEC 61508 series and specifies several safety communication layers (profiles and
corresponding protocols) based on the communication profiles and protocol layers of
IEC 61784-2 and the IEC 61158 series. It does not cover electrical safety and intrinsic safety
aspects.
Figure 1 shows the relationships between this standard and relevant safety and fieldbus
standards in a machinery environment.
IEC
NOTE Subclauses 6.7.6.4 (high complexity) and 6.7.8.1.6 (low complexity) of IEC 62061 specify the relationship
between PL (Category) and SIL.
Figure 1 – Relationships of IEC 61784-3 with other standards (machinery)

– 8 – IEC 61784-3-17:2016  IEC 2016
Figure 2 shows the relationships between this standard and relevant safety and fieldbus
standards in a process environment.
IEC
a
For specified electromagnetic environments; otherwise IEC 61326-3-1 or IEC 61000-6-7.
b
EN ratified.
Figure 2 – Relationships of IEC 61784-3 with other standards (process)
Safety communication layers which are implemented as parts of safety-related systems
according to IEC 61508 series provide the necessary confidence in the transportation of
messages (information) between two or more participants on a fieldbus in a safety-related
system, or sufficient confidence of safe behaviour in the event of fieldbus errors or failures.
Safety communication layers specified in this standard do this in such a way that a fieldbus
can be used for applications requiring functional safety up to the Safety Integrity Level (SIL)
specified by its corresponding functional safety communication profile.
The resulting SIL claim of a system depends on the implementation of the selected functional
safety communication profile (FSCP) within this system – implementation of a functional
safety communication profile in a standard device is not sufficient to qualify it as a safety
device.
IEC 61784-3-17:2016  IEC 2016 – 9 –
This standard describes:
• basic principles for implementing the requirements of IEC 61508 series for safety-
related data communications, including possible transmission faults, remedial
measures and considerations affecting data integrity;
• functional safety communication profiles for several communication profile families in
IEC 61784-1 and IEC 61784-2, including safety layer extensions to the communication
service and protocols sections of the IEC 61158 series.
0.2 Patent declaration
The International Electrotechnical Commission (IEC) draws attention to the fact that it is
claimed that compliance with this document may involve the use of patents concerning the
functional safety communication profiles for family 17 as follows, where the [xx] notation
indicates the holder of the patent right:
PCT/KR2012/008651 [LSIS] Communication apparatus and Communication method
PCT/KR2012/008653 [LSIS] Communication apparatus and Communication method
PCT/KR2012/008654 [LSIS] Communication apparatus and Communication method
PCT/KR2012/008655 [LSIS] Communication apparatus and Communication method
KR 10-1389604 [LSIS] Communication Device and communication method
KR 10-1442963 [LSIS] Communication Device and communication method
KR 10-1389646 [LSIS] Communication Device and communication method
IEC takes no position concerning the evidence, validity and scope of these patent rights.
The holders of these patents rights have assured the IEC that they are willing to negotiate
licences either free of charge or under reasonable and non-discriminatory terms and
conditions with applicants throughout the world. In this respect, the statements of the holders
of these patent rights are registered with IEC.
Information may be obtained from:
LSIS Co Ltd
[LSIS]
LS Tower
1026-6, Hogye-Dong
Dongan-Gu
Anyang, Gyeonggi-Do, 431-848
South Korea
Attention is drawn to the possibility that some of the elements of this document may be the
subject of patent rights other than those identified above. IEC shall not be held responsible for
identifying any or all such patent rights.

– 10 – IEC 61784-3-17:2016  IEC 2016
INDUSTRIAL COMMUNICATION NETWORKS –
PROFILES –
Part 3-17: Functional safety fieldbuses –
Additional specifications for CPF 17

1 Scope
This part of the IEC 61784-3 series specifies a safety communication layer (services and
protocol) based on CPF 17 of IEC 61784-2 (CP 17/1) and IEC 61158 Type 21. It identifies the
principles for functional safety communications defined in IEC 61784-3 that are relevant for
this safety communication layer. This safety communication layer is intended for
implementation in safety devices only.
NOTE 1 It does not cover electrical safety and intrinsic safety aspects. Electrical safety is related to hazards such
as electrical shock. Intrinsic safety is related to hazards associated with potentially explosive atmospheres.
This part defines mechanisms for the transmission of safety-relevant messages among
participants within a distributed network using fieldbus technology in accordance with the
requirements of IEC 61508 series for functional safety. These mechanisms may be used in
various industrial applications such as process control, manufacturing automation, and
machinery.
This part provides guidelines for both developers and assessors of compliant devices and
systems.
NOTE 2 The resulting SIL claim of a system depends on implementation of the selected functional safety
communication profile within this system; implementation of a functional safety communication profile according to
this part in a standard device is not sufficient for it to qualify as a safety device.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 61000-6-2, Electromagnetic compatibility (EMC) – Part 6-2: Generic standards –
Immunity for industrial environments
IEC 61131-2, Programmable controllers – Part 2: Equipment requirements and tests
IEC 61158-3-21:2010, Industrial communication networks – Fieldbus specifications –
Part 3-21: Data-link layer service definition – Type 21 elements
IEC 61158-4-21:2010, Industrial communication networks – Fieldbus specifications –
Part 4-21: Data-link layer protocol specification – Type 21 elements
IEC 61158-5-21:2010, Industrial communication networks – Fieldbus specifications –
Part 5-21: Application layer service definition –Type 21 elements
____________
1 In the following pages of this standard, “this part” will be used for “this part of the IEC 61784-3 series.”
2 In the following pages of this standard, “IEC 61508” will be used for “IEC 61508 series.”

IEC 61784-3-17:2016  IEC 2016 – 11 –
IEC 61158-6-21:2010, Industrial communication networks – Fieldbus specifications –
Part 6-21: Application layer protocol specification – Type 21 elements
IEC 61326-3-1, Electrical equipment for measurement, control, and laboratory use – EMC
requirements – Part 3-1: Immunity requirements for safety-related systems and for equipment
intended to perform safety-related functions (functional safety) – General industrial
applications
IEC 61326-3-2, Electrical equipment for measurement, control, and laboratory use – EMC
requirements – Part 3-2: Immunity requirements for safety-related systems and for equipment
intended to perform safety-related functions (functional safety) – Industrial applications with
specified electromagnetic environment
IEC 61508 (all parts), Functional safety of electrical/electronic/programmable electronic
safety-related systems
IEC 61508-1:2010, Functional safety of electrical/electronic/programmable electronic safety-
related systems – Part 1: General requirements
IEC 61784-2, Industrial communication networks – Profiles – Part 2: Additional fieldbus
profiles for real-time networks based on ISO/IEC 8802-3
, Industrial communication networks – Profiles – Part 3: Functional safety
IEC 61784-3:—
fieldbuses – General rules and profile definitions
IEC 61784-5-17:2013, Industrial communication networks – Profiles – Part 5: Installation of
fieldbuses – Installation profiles for CPF 17
IEC 61918, Industrial communication networks – Installation of communication networks in
industrial premises
3 Terms, definitions, symbols, abbreviated terms, and conventions
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
NOTE Italics are used in the definitions to highlight terms which are themselves defined in 3.1.
3.1.1 Common terms and definitions
NOTE These common terms and definitions are inherited from IEC 61784-3:—.
3.1.1.1
availability
probability in an automated system that for a given period of time, there are no unsatisfactory
system conditions such as loss of production
3.1.1.2
black channel
defined communication system containing one or more elements without evidence of design
or validation according to IEC 61508
Note 1 to entry: This definition expands the usual meaning of channel to include the system that contains the
channel.
____________
To be published.
– 12 – IEC 61784-3-17:2016  IEC 2016
3.1.1.3
closed communication system
fixed number or fixed maximum number of participants linked by a communication system with
well-known and fixed properties, and where the risk of unauthorized access is considered
negligible
[SOURCE: IEC 62280:2014, 3.16, modified – transmission replaced by communication]
3.1.1.4
communication channel
logical connection between two end-points within a communication system
3.1.1.5
communication system
arrangement of hardware, software, and propagation media to allow the transfer of messages
(ISO/IEC 7498-1 application layer) from one application to another
3.1.1.6
connection
logical binding between two application objects within the same or different devices
3.1.1.7
Cyclic Redundancy Check
CRC
redundant data derived from, and stored or transmitted together with, a block of data
to detect data corruption
procedure used to calculate the redundant data
Note 1 to entry: Terms “CRC code” and “CRC signature” and labels such as CRC1, CRC2 may also be used in
this standard to refer to redundant data.
Note 2 to entry: See also [34], [35] .
3.1.1.8
defined communication system
defined channel
fixed number or fixed maximum number of participants linked by a fieldbus based
communication system with well-known and fixed properties, such as installation conditions,
electromagnetic immunity, industrial (active) network elements, and where the risk of
unauthorized access is reduced to a tolerated level according to the lifecycle model of
IEC 62443, using for example zones and conduits
3.1.1.9
error
discrepancy between a computed, observed, or measured value or condition and the true,
specified, or theoretically correct value or condition
Note 1 to entry: Errors may be due to design mistakes within hardware/software and/or corrupted information due
to electromagnetic interference and/or other effects.
Note 2 to entry: Errors do not necessarily result in a failure or a fault.
[SOURCE: IEC 61508-4:2010, 3.6.11, modified – notes added]
____________
Figures in square brackets refer to the bibliography.

IEC 61784-3-17:2016  IEC 2016 – 13 –
3.1.1.10
failure
termination of the ability of a functional unit to perform a required function or operation of a
functional unit in any way other than as required
Note 1 to entry: Failure may be due to an error (for example, problem with hardware/software design or message
disruption).
[SOURCE: IEC 61508-4:2010, 3.6.4, modified – notes and figures replaced]
3.1.1.11
fault
abnormal condition that may cause a reduction in or loss of the capability of a functional unit
to perform a required function
Note 1 to entry: IEC 60050-191:1990, 191.05.01 defines “fault” as a state characterized by the inability to
perform a required function, excluding such inability during preventive maintenance or other planned actions or due
to lack of external resources.
[SOURCE: IEC 61508-4:2010, 3.6.1, modified – figure reference deleted]
3.1.1.12
fieldbus
communication system based on serial data transfer and used in industrial automation or
process-control applications
3.1.1.13
fieldbus system
system using a fieldbus with connected devices
3.1.1.14
frame
denigrated synonym for DLPDU
3.1.1.15
Frame Check Sequence
FCS
redundant data derived from a block of data within a DLPDU (frame) using a hash function
and stored or transmitted together with the block of data to detect data corruption
Note 1 to entry: An FCS can be derived using for example a CRC or other hash function.
Note 2 to entry: See also [34], [35].
3.1.1.16
hash function
(mathematical) function that maps values from a (possibly very) large set of values into a
(usually) smaller range of values
Note 1 to entry: Hash functions can be used to detect data corruption.
Note 2 to entry: Common hash functions include parity, checksum, or CRC.
[SOURCE: IEC TR 62210:2003, 4.1.12, modified – addition of “usually” and notes]
3.1.1.17
hazard
state or set of conditions of a system that, together with other related conditions, will
inevitably lead to harm to persons, property, or the environment

– 14 – IEC 61784-3-17:2016  IEC 2016
3.1.1.18
message
ordered series of octets intended to convey information
[SOURCE: ISO/IEC 2382-16:1996, 16.02.01, modified – character replaced by octet]
3.1.1.19
nuisance trip
spurious trip with no harmful effect
Note 1 to entry: Internal abnormal errors can arise in communication systems, such as wireless transmission, for
example, by too many retries in the presence of interference.
3.1.1.20
proof test
...