IEC 61784-3-18:2011/AMD2:2021

IEC 61784-3-18 ®
Edition 1.0 2021-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
A MENDMENT 2
AM ENDEMENT 2
Industrial communication networks – Profiles –
Part 3-18: Functional safety fieldbuses – Additional specifications for CPF 18
Réseaux de communication industriels – Profils –
Partie 3-18: Bus de terrain de sécurité fonctionnelle – Spécifications
supplémentaires pour CPF 18
IEC 61784-3-18:2011-04/AMD2:2021-04(en-fr)

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IEC 61784-3-18 ®
Edition 1.0 2021-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
A MENDMENT 2
AM ENDEMENT 2
Industrial communication networks – Profiles –
Part 3-18: Functional safety fieldbuses – Additional specifications for CPF 18
Réseaux de communication industriels – Profils –
Partie 3-18: Bus de terrain de sécurité fonctionnelle – Spécifications
supplémentaires pour CPF 18
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 25.040.40; 35.100.05 ISBN 978-2-8322-9757-5
– 2 – IEC 61784-3-18:2011/AMD2:2021
© IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL COMMUNICATION NETWORKS –
PROFILES –
Part 3-18: Functional safety fieldbuses –
Additional specifications for CPF 18

AMENDMENT 2
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,
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in the subject dealt with may participate in this preparatory work. International, governmental and non-
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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
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Amendment 2 to IEC 61784-3-18:2011 has been prepared by subcommittee 65C: Industrial
networks, of IEC technical committee 65: Industrial-process measurement, control and
automation.
© IEC 2021
The text of this Amendment is based on the following documents:
FDIS Report on voting
65C/1083/FDIS 65C/1087/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/standardsdev/publications.
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 document will remain unchanged until the
stability date indicated on the IEC website under "http://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.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates that it
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_____________
INTRODUCTION to Amendment 2
This Amendment 2 introduces several editorial and informational corrections in the context of
Edition 4 of IEC 61784-3.
– 4 – IEC 61784-3-18:2011/AMD2:2021
© IEC 2021
0 Introduction
0.1 General
Replace the existing Figure 1 by the following new figure:

Replace the existing text of the NOTE below Figure 1 (before the title) by the following:
IEC 62061 specifies the relationship between PL (Category) and SIL.

© IEC 2021
Replace the existing Figure 2 by the following new figure:

Replace, below Figure 2, the existing text of figure footnote a by the following:
For specified electromagnetic environments; otherwise IEC 61326-3-1 or IEC 61000-6-7.
Delete, below Figure 2, figure footnote b.
5 General
5.1 External documents providing specifications for the profile
Replace the existing text by the following:
There is no additional external document used for FSCP 18/1.
7 Safety communication layer protocol
7.1.2.4 Safety data
Delete, at the end of second paragraph: "as proven in 9.5.2".
7.1.2.7 SPDO CRC
Replace, in second paragraph: "0x20044009" with "0x120044009".

– 6 – IEC 61784-3-18:2011/AMD2:2021
© IEC 2021
Replace, at the end of second paragraph: "9.5.2" with "Clause A.1".
7.1.3.8 SHB CRC
Replace, in second paragraph: "0x20044009" with "0x120044009".
Replace, at the end of second paragraph: "9.5.2" with "Clause A.1".
9 System requirements
9.5 Constraints for calculation of system characteristics
Delete Subclause 9.5.2.
Annex A – Additional information for functional safety communication profiles
of CPF 18
Delete the sentence: "There is no additional information for this FSCP. "
Add the following new Clauses A.1 and A.2.
A.1 Hash function calculation
The 32-bit CRC used in this FSCP is 0x120044009. It is calculated by:
G(x) = x32 + x29 + x18 + x14 + x3 + 1
Table A.1 contains the residual error probabilities for the used 32-bit polynomial for different
code length and bit error probabilities in the range of 120 bits up to data lengths of 1 024 bits
(128 octets) as specified in 9.5.1.4 including the CRC signature and incorporating the overall
safety PDU structure as described in 7.1.
Table A.1 – Residual error probabilities for CRC32 Polynomial 0x120044009
Length P = 0,000 1 P = 0,001 P = 0,01 P = 2/n P = 4/n P = 8/n
BER BER BER BER BER BER
n (bits)
(2/n < 0,01) (4/n < 0,01) (8/n < 0,01)
120 1,4236765E-22 1,2847875E-16 4,5824514E-11 - - -
128 1,5805978E-22 1,4161637E-16 4,6991099E-11 - - -
136 1,8162338E-22 1,6156082E-16 4,9874896E-11 - - -
144 2,0514920E-22 1,8117854E-16 5,2040784E-11 - - -
152 2,2863728E-22 2,0047350E-16 5,3582492E-11 - - -
160 2,5208766E-22 2,1944972E-16 5,4586144E-11 - - -
168 2,7550040E-22 2,3811128E-16 5,5130780E-11 - - -
176 2,9887554E-22 2,5646232E-16 5,5287180E-11 - - -
184 3,2221313E-22 2,7450668E-16 5,5112762E-11 - - -
192 3,4551322E-22 2,9224828E-16 5,4660017E-11 - - -
200 3,6877585E-22 3,0969120E-16 5,3978908E-11 - - -
208 3,9200108E-22 3,2683958E-16 5,3114126E-11 4,5363410E-11 - -
216 4,1518896E-22 3,4369773E-16 5,2107322E-11 3,8340651E-11 - -

© IEC 2021
Length P = 0,000 1 P = 0,001 P = 0,01 P = 2/n P = 4/n P = 8/n
BER BER BER BER BER BER
n (bits)
(2/n < 0,01) (4/n < 0,01) (8/n < 0,01)
224 4,3833955E-22 3,6026990E-16 5,0993464E-11 3,2582177E
...