IEC 61784-3-6:2007

IEC 61784-3-6 ®
Edition 1.0 2007-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Industrial communication networks – Profiles –
Part 3-6: Functional safety fieldbuses – Additional specifications for CPF 6

Réseaux de communications industriels – Profils –
Partie 3-6: Bus de terrain de sécurité fonctionnelle – Spécifications
supplémentaires pour la CPF 6
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IEC 61784-3-6 ®
Edition 1.0 2007-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Industrial communication networks – Profiles –

Part 3-6: Functional safety fieldbuses – Additional specifications for CPF 6

Réseaux de communications industriels – Profils –

Partie 3-6: Bus de terrain de sécurité fonctionnelle – Spécifications

supplémentaires pour la CPF 6
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XC
ICS 25.040; 35.100.05 ISBN 978-2-8322-0845-8

– 2 – 61784-3-6 © IEC:2007
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 12
2 Normative references . 12
3 Terms, definitions, symbols, abbreviated terms and conventions . 13
3.1 Terms and definitions . 13
3.1.1 Common terms and definitions . 13
3.1.2 CPF 6: Additional terms and definitions . 17
3.2 Symbols and abbreviated terms. 18
3.2.1 Common symbols and abbreviated terms . 18
3.2.2 CPF 6: Additional symbols and abbreviated terms . 18
3.3 Conventions . 19
4 Overview of FSCP 6/7 (INTERBUS™ Safety) . 19
4.1 General . 19
4.2 Technical overview . 19
4.3 Functional Safety Communication Profile 6/7 . 20
5 General . 21
5.1 External documents providing specifications for the profile . 21
5.2 Safety functional requirements . 21
5.3 Safety measures . 21
5.3.1 General . 21
5.3.2 Sequence number . 22
5.3.3 Time stamp . 22
5.3.4 Time expectation . 22
5.3.5 Acknowledgement . 22
5.3.6 Connection authentication . 22
5.3.7 Distinction between safety relevant messages and non-safety
relevant messages – different data integrity assurance system . 23
5.3.8 Parameterized shutdown time . 23
5.4 Safety communication layer structure . 23
5.4.1 Decomposition process. 23
5.4.2 Definition of the safety function of the safety communication system . 24
5.4.3 Decomposition of the safety function of a safety communication
system into function blocks . 25
5.4.4 Assignment of the function blocks to subsystems . 26
5.4.5 Safety requirements and safety integrity requirements . 29
5.4.6 Specification of the safe state . 29
5.4.7 Response to a fault . 30
5.4.8 Stop category . 32
5.4.9 Safe Transmission . 32
5.5 Relationships with FAL (and DLL, PhL) . 33
5.5.1 Overview . 33
5.5.2 Use of the AR-US service to initiate and parameterize . 33
5.5.3 Use of the AR-US service to transmit safety data . 34
5.5.4 Use of the AR-US service to abort . 35
5.5.5 Data types . 35

61784-3-6 © IEC:2007 – 3 –
6 Safety communication layer services . 35
6.1 General . 35
6.2 Transmission principle for safety messages between SCLM and SCLS . 35
6.3 Function block requirements . 36
6.3.1 Input Safe Data function block . 36
6.3.2 Output Safe Data function block . 36
6.3.3 Safe Calculation function block . 36
6.4 Context management . 37
6.4.1 Initiate service . 37
6.4.2 Abort service . 38
6.5 Function block parameterization . 39
6.5.1 Send application parameter service . 39
6.5.2 Send application parameter ID service . 40
6.5.3 Parameterize device service . 41
6.6 Safe Process Data Mode . 41
6.6.1 Transmit-Safety-Data . 41
6.6.2 Set-Diagnostic-Data service . 43
6.6.3 Set-Acknowledgement-Data service . 43
7 Safety communication layer protocol . 44
7.1 Safety PDU format . 44
7.1.1 Structure of safety messages . 44
7.1.2 Description of the polynomial used . 45
7.1.3 Structure of safety messages for safe parameterization and idle . 45
7.1.4 Structure of safety messages for the transmission of safety data . 51
7.1.5 Messages for synchronization . 52
7.1.6 Structure of safety messages for aborting connections . 53
7.2 State description . 54
7.2.1 SCLM and SCLS state machines . 54
7.2.2 Initiate . 55
7.2.3 Parameterization . 56
7.2.4 Process data mode . 59
7.2.5 Process data mode with diagnostic data transmission . 64
7.2.6 Process data mode with Acknowledgement-Data transmission . 65
7.2.7 Connection aborted . 66
7.3 Abort . 66
7.3.1 Connection abort in the event of an error detected by the SCLM . 66
7.3.2 Abort of all connections in the event of an error detected by the
SCLS . 67
7.3.3 Abort of all connections in the event of an error detected by the
SCLM . 69
8 Safety communication layer management . 70
8.1 General . 70
8.2 Requirements of safety communication layer management . 70
8.3 Set-Safety-Configuration service . 70
8.4 Start IEC 61158 Type 8 service . 72
9 System requirements . 72
9.1 Indicators and switches . 72
9.2 Installation guidelines . 72
9.3 Safety function response time . 72

– 4 – 61784-3-6 © IEC:2007
9.3.1 General . 72
9.3.2 Calculation of the parameterized shutdown time . 73
9.4 Duration of demands . 77
9.5 Constraints for calculation of system characteristics . 77
9.5.1 System characteristics . 77
9.5.2 Calculation of the number of telegrams per second . 77
9.6 Maintenance . 78
9.7 Safety manual . 79
10 Certification . 79
Bibliography . 80

Table 1 – Overview of profile identifier usable for FSCP 6/7. 21
Table 2 – Selection of the various measures for possible errors . 22
Table 3 – List of function blocks and subsystems . 26
Table 4 – Signal flow between the function blocks . 28
Table 5 – Initiate service parameters . 37
Table 6 – Parameterization mode and related services . 38
Table 7 – Abort service parameters . 38
Table 8 – Abort of a point-to-point connection by the SRP or SRC . 39
Table 9 – Send application parameter service . 39
Table 10 – Send application parameter ID service . 40
Table 11 – Parameterize device parameters . 41
Table 12 – Transmit-Safety-Data service parameters . 42
Table 13 – Set-Diagnostic-Data service parameters . 43
Table 14 – Set-Acknowledgement-Data service parameters . 44
Table 15 – Parameter ID . 47
Table 16 – Block 0: Device ID . 48
Table 17 – Block 1: Parameter record ID . 49
Table 18 – Block 2: Application parameter . 49
Table 19 – TIME encoding . 52
Table 20 – Abort_Info: Connection abort in the event of an error detected by the SCLM . 67
Table 21 – Abort_Info: Abort of all connections in the event of an error detected by the
SCLS . 68
Table 22 – Abort_Info: Abort of all connections in the event of an error detected by the
SCLM . 70
Table 23 – Set-Safety-Configuration service . 71
Table 24 – Error_Info . 71
Table 25 – Calculation of t . 76
IB
Table 26 – Calculation of t . 77
SRC
Table 27 – Calculation of t . 77
PST
Figure 1 – Relationships of IEC 61784-3 with other standards (machinery) . 9
Figure 2 – Relationships of IEC 61784-3 with other standards (process) . 10

61784-3-6 © IEC:2007 – 5 –
Figure 3 – FSCP 6/7 communication preconditions . 20
Figure 4 – Example of a safety function . 24
Figure 5 – Decomposition of safety function into function blocks . 25
Figure 6 – Overview of the results of the decomposition process . 27
Figure 7 – Signal flow between the function blocks . 27
Figure 8 – Interfaces between the safety devices within the safety communication
system . 28
Figure 9 – Signal flow and safe states . 30
Figure 10 – Mapping of the Safe Transmission function block . 32
Figure 11 – Relationship between SCL and the other layers of IEC 61158 Type 8. 33
Figure 12 – Use of the AR-US service to initiate and parameterize . 34
Figure 13 – Use of the AR-US service to transmit safety data . 34
Figure 14 – Use of the AR-US service to abort . 35
Figure 15 – Use of the AR-US service to abort . 35
Figure 16 – Structure of the safety PDU . 44
Figure 17 – Integration of safety data and deterministic remedial measures in the
summation frame . 45
Figure 18 – Write_Parameter_Byte_Req message . 46
Figure 19 – Read_Parameter_Byte_Req message . 46
Figure 20 – Parameter_Byte_Con message . 46
Figure 21 – Set_Safety_Connection_ID_Req message . 50
Figure 22 – Set_Safety_Connection_ID_Con message of safety slaves . 50
Figure 23 – Parameter_Idle_Req . 50
Figure 24 – Parameter_Idle_Con . 50
Figure 25 – Parameter_Check_Con . 51
Figure 26 – Parameter_Loc_ID_Changed_Con . 51
Figure 27 – Transmit Safety Data Message . 51
Figure 28 – Sync_a message of the SCLM. 52
Figure 29 – Req_b message of the SCLM . 53
Figure 30 – Req_c message of the SCLM . 53
Figure 31 – Req_d message of the SCLM . 53
Figure 32 – Abort_Connection message . 54
Figure 33 – Safety-Slave_Error message . 54
Figure 34 – SCLM state machine . 54
Figure 35 – SCLS state machine . 55
Figure 36 – Initiate sequence . 56
Figure 37 – Send Application Parameter sequence . 57
Figure 38 – Send Application Parameter ID sequence . 58
Figure 39 – Parameterize device sequence . 59
Figure 40 – Simultaneous transmission of safety data to the safety slaves . 60
Figure 41 – Use of the sequence number in the SCLM and SCLS . 61
Figure 42 – Startup and error-free operation . 62
Figure 43 – Resynchronization during operation . 63
Figure 44 – Invalid CRC 24 checksum detected by the SCLS . 64

– 6 – 61784-3-6 © IEC:2007
Figure 45 – Process data mode with diagnostic data transmission . 65
Figure 46 – Process data mode with Acknowledgement-Data transmission . 66
Figure 47 – Error when initiating a connection . 67
Figure 48 – Error at an SCLS when aborting all connections . 68
Figure 49 – Abort of all connections in the event of an error detected by the SCLM . 69
Figure 50 – Overview of the shutdown time . 74

61784-3-6 © IEC:2007 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL COMMUNICATION NETWORKS –
PROFILES –
Part 3-6: Functional safety fieldbuses –
Additional specifications for CPF 6

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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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
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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
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5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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.
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 6 as follows, where the [xx] notation indicates the holder of the patent right:
DE 103 25 263 A1 [PxC] Sicherstellung von maximalen Reaktionszeiten in
komplexen oder verteilten sicheren und/oder nicht
sicheren Systemen
DE 103 18 068 A1 [PxC] Verfahren und Vorrichtung zum Paket-orientierten
Übertragen sicherheitsrelevanter Daten
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 under
reasonable and non-discriminatory terms and conditions with applicants throughout the world. In this respect, the
statement of the holders of these patent rights are registered with IEC.

– 8 – 61784-3-6 © IEC:2007
Information may be obtained from:
[PxC] Phoenix Contact GmbH & Co. KG
Intellectual Property Licenses &
Standards
Flachsmarktstr. 8
D-32825 Blomberg,
Germany
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.
International Standard IEC 61784-3-6 has been prepared by subcommittee 65C: Industrial
networks, of IEC technical committee 65: Industrial process measurement, control and
automation.
This bilingual version (2013-07) corresponds to the monolingual English version, published in
2007-12.
The text of this standard is based on the following documents:
FDIS Report on voting
65C/470/FDIS 65C/481/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.
The French version of this standard has not been voted upon.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result 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.
The list of all parts of the IEC 61784-3 series, under the general title Industrial communication
networks – Profiles – Functional safety fieldbuses, can be found on the IEC website.

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.
61784-3-6 © IEC:2007 – 9 –
INTRODUCTION
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 many fieldbus enhancements are emerging, addressing not yet standardized
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 61784-1, 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.
Product standards
ISO 12100-1 and ISO 14121
ISO 12100-1 and ISO 14121
IEC 61496 IEC 61131-6 IEC 61800-5-2 Safety of machinery – Principles for
Safety of machinery – Principles for
IEC 61496 IEC 61131-6 IEC 61800-5-2
Safety f. e.g. SafSaetfye tfyorf PorLC Safety functions design and risk assessment
design and risk assessment
Safety f. e.g. Safety for Safety functions
light curtains (under cPonsLCideration) for drives
light curtains PLC for drives
IEC 61784-4 IEC 62443 Design of safety-related electrical, electronic and programmable
IEC 61784-4 IEC 62443
electronic control systems (SRECS) for machinery
Security Security
Security Security
(profile-specific) (common part)
(profile-specific) (common part)
SIL based PL based
IEC 61784-5 IEC 61918
IEC 61784-5 IEC 61918
Design objective
Installation guide Installation guide
Installation guide Installation guide
(profile-specific) (common part) Applicable standards
(profile-specific) (common part)
ISO 13849-1, -2
ISO 13849-1, -2
IEC 60204-1
IEC 60204-1
Safety-related parts
Safety-related parts
Safety of electrical
Safety of electrical
IEC 61326-3-1 of machinery
IEC 61326-3-1 of machinery
equipment
equipment
EMC and (SRPCS)
EMC and (SRPCS)
functional safety
functional safety
IEC 61784-3
IEC 61784-3
Non-electrical
Non-electrical
Functional safety
Functional safety
communication
communication
Electrical
Electrical
US: NFPA 79
US: NFPA 79
profiles
profiles
(2006)
(2006)
IEC 62061
IEC 62061
Functional safety
Functional safety
IEC 61158 series /
IEC 61158 series /
for machinery
for machinery
IEC 61784-1, -2 IEC 61508 series
IEC 61784-1, -2 IEC 61508 series (SRECS)
(SRECS)
Functional safety
Fieldbus for use in Functional safety (including EMI for
Fieldbus for use in
(including EMI for
(basic standard)
industrial environment)
industrial control systems (basic standard)
industrial environment)
industrial control systems
Key
(yellow) safety-related standards
(blue) fieldbus-related standards
(dashed yellow) this standard
Figure 1 – Relationships of IEC 61784-3 with other standards (machinery)

– 10 – 61784-3-6 © IEC:2007
Figure 2 shows the relationships between this standard and relevant safety and fieldbus
standards in a process environment.
Product standards
IEC 61496 IEC 61131-6 IEC 61800-5-2
IEC 61496 IEC 61131-6 IEC 61800-5-2
Safety f. e.g. SafSetafyet foyrf PorLC Safety functions
Safety f. e.g. Safety for Safety functions
(under consideration)
light curtains PLC for drives
light curtains PLC for drives
IEC 61784-4 IEC 62443
IEC 61784-4 IEC 62443
Security Security
Security Security
(profile-specific) (common part)
(profile-specific) (common part)
See safety standards for machinery
(Figure 1)
IEC 61784-5 IEC 61918
IEC 61784-5 IEC 61918
Installation guide Installation guide
Installation guide Installation guide
(profile-specific) (common part)
(profile-specific) (common part)
Valid also in process industries,
whenever applicable
a)
a)
IEC 61326-3-2
IEC 61326-3-2
EMC and
EMC and
functional safety
functional safety
IEC 61784-3
IEC 61784-3
Functional safety
Functional safety
communication
communication
profiles
profiles
US:
US:
ISA-84.00.01
ISA-84.00.01
b)
b)
IEC 61511 series (3 parts = modified
IEC 61511 series (3 parts = modified
Functional safety – IEC 61511)
IEC 61158 series / Functional safety – IEC 61511)
IEC 61158 series /
Safety instrumented
Safety instrumented
IEC 61784-1, -2 IEC 61508 series
IEC 61784-1, -2 IEC 61508 series
systems for the
systems for the
Functional safety
Fieldbus for use in
Functional safety
Fieldbus for use in DE: VDI 2180
DE: VDI 2180
process industry sector
process industry sector
(basic standard)
(basic standard)
industrial control systems Part 1-4
industrial control systems
Part 1-4
Key
(yellow) safety-related standards
(blue) fieldbus-related standards
(dashed yellow) this standard
a
For specified electromagnetic environments; otherwise IEC 61326-3-1.
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 within this system – implementation of a functional safety
communication profile in a standard device is not sufficient to qualify it as a safety device.

61784-3-6 © IEC:2007 – 11 –
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;
 individual description of functional safety profiles for several communication profile
families in IEC 61784-1 and IEC 61784-2;
 safety layer extensions to the communication service and protocols sections of the
IEC 61158 series.
– 12 – 61784-3-6 © IEC:2007
INDUSTRIAL COMMUNICATION NETWORKS –
PROFILES –
Part 3-6: Functional safety fieldbuses –
Additional specifications for CPF 6

1 Scope
This part of the IEC 61784-3 series specifies a safety communication layer (services and
protocol) based on CPF 6 of IEC 61784-1, IEC 61784-2 and IEC 61158 Type 8. It identifies
the principles for functional safety communications defined in IEC 61784-3 that are relevant
for this safety communication layer.
NOTE 1 It does not cover electrical safety and intrinsic safety aspects. Electrical safety relates to hazards such
as electrical shock. Intrinsic safety relates 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 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 the 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 to qualify it as a safety device.
2 Normative references
The following referenced documents are indispensable for the application 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.
IEC 61131-3, Programmable controllers – Part 3: Programming languages
IEC 61158-2, Industrial communication networks – Fieldbus specifications – Part 2: Physical
layer specification and service definition
IEC 61158-3-8, Industrial communication networks – Fieldbus specifications – Part 3-8: Data-
link layer service definition
IEC 61158-4-8, Industrial communication networks – Fieldbus specifications – Part 4-8: Data-
link layer protocol specification
IEC 61158-5-8, Industrial communication networks – Fieldbus specifications – Part 5-8:
Application layer service definition
IEC 61158-6-8, Industrial communication networks – Fieldbus specifications – Part 4-8:
Application layer protocol specification
—————————
In the following pages of this standard, “this part” will be used for “this part of the IEC 61784-3 series”.

61784-3-6 © IEC:2007 – 13 –
IEC 61508 (all parts), Functional safety of electrical/electronic/programmable electronic
safety-related systems
IEC 61784-1, Industrial communication networks – Profiles – Part 1: Fieldbus profiles
IEC 61784-2, Industrial communication networks – Profiles – Part 2: Additional fieldbus
profiles for real-time networks based on ISO/IEC 8802-3
IEC 61784-3, Industrial communication networks – Profiles – Part 3: Functional safety
fieldbuses – General rules and profile definitions
IEC 61784-5-6, Industrial communication networks – Profiles – Part 5: Installation of
fieldbuses – Installation profiles for CPF 6
IEC 61918, Industrial communication networks – Installation of communication networks in
industrial premises
IEC 62061, Safety of machinery – Functional safety of safety-related electrical, electronic and
programmable electronic control systems
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.
3.1.1 Common terms and definitions
3.1.1.1
availability
probability for an automated system that for a given period of time there are no unsatisfactory
system conditions such as loss of production
NOTE Availability depends on MTBF (mean time between failure) and MDT (mean down time):
Availability = MTBF / (MTBF + MDT).
3.1.1.2
communication system
arrangement of hardware, software and propagation media to allow the transfer of messages
(ISO/IEC 7498 application layer) from one application to another
3.1.1.3
connection
logical binding between two application objects within the same or different devices
3.1.1.4
Cyclic Redundancy Check (CRC)
redundant data derived from, and stored or transmitted together with, a block of data
in order to detect data corruption
procedure used to calculate the redundant data
NOTE 1 Terms “CRC code” and "CRC signature" , and labels such as CRC1, CRC2, may also be used in this
standard to refer to the redundant data.
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