IEC 61158-4-2:2007

Industrial communication networks - Fieldbus specifications - Part 4-2: Data-link layer protocol specification - Type 2 elements

IEC 61158-4-2:2007 describes the protocol that provides communication opportunities to all participating data-link entities, sequentially and in a cyclic synchronous manner. Foreground scheduled access is available for time-critical activities together with background unscheduled access for less critical activities. This protocol optimizes each access opportunity by concatenating multiple DLSDUs and associated DLPCI into a single DLPDU, thereby improving data transfer efficiency for data-link entities that actively source multiple streams of data. This first edition and its companion parts of the IEC 61158-4 subseries cancel and replace IEC 61158-4:2003. This edition of this part constitutes a minor revision. This part and its companion Type 2 parts also cancel and replace IEC/PAS 62413, published in 2005. This edition of IEC 61158-4 includes the following changes:
- deletion of the former Type 6 fieldbus, and the placeholder for a Type 5 fieldbus data link layer, for lack of market relevance;
- addition of new types of fieldbuses;
- division of this part into multiple parts numbered -4 1, -4 2, , -4-19. This bilingual version (2014-07) corresponds to the English version, published in 2007-12.

Réseaux de communication industriels - Spécifications des bus de terrain - Partie 4-2: Spécification du protocole de la couche liaison de données - Eléments de type 2

L'IEC 61158-4-2:2007 décrit un protocole qui offre des opportunités de communication séquentielle et synchrone cyclique à toutes les entités de liaison de données participantes. Un accès planifié de premier plan est proposé à toutes les activités à contrainte de temps, un accès non planifié l'étant aux activités moins critiques. Ce protocole permet d'optimiser chaque opportunité d'accès en concaténant plusieurs DLSDU et DLPCI associés en une seule DLPDU, améliorant le transfert de données des entités de liaison de données qui émettent activement plusieurs flux de données. Cette première édition et ses parties d'accompagnement de la sous-série CEI 61158-4 annulent et remplacent la CEI 61158-4:2003. Elle constitue une révision mineure. Cette partie et ses parties d'accompagnement pour le Type 2 annulent et remplacent également la CEI/PAS 62413, publiée en 2005. Elle inclut les modifications suivantes:
- suppression du précédent bus de terrain de Type 6 et de la référence à une couche de liaison de données de bus de terrain de Type 5, en raison du manque d'adéquation au marché;
- ajout de nouveaux types de bus de terrain; division de cette partie en parties multiples numérotées -4 1, -4 2, , -4-19. La présente version bilingue (2014-07) correspond à la version anglaise monolingue publiée en 2007-12.

General Information

• Status: Published
• Publication Date: 13-Dec-2007
• ICS: 25.040.40 - Industrial process measurement and control
• ICS: 35.100.20 - Data link layer
• Technical Committee: SC 65C - Industrial networks
• Drafting Committee: WG 9 - TC 65/SC 65C/WG 9
• Current Stage: DELPUB - Deleted Publication
• Start Date: 06-Aug-2010
• Completion Date: 26-Oct-2025

Relations

• Replaces: IEC PAS 62413:2005 - Real-time Ethernet - EtherNet/IP(TM) with time synchronization
• Effective Date: 05-Sep-2023
• Replaces: IEC 61158-4:2003 - Digital data communications for measurement and control - Fieldbus for use in industrial control systems - Part 4: Data link protocol specification
• Effective Date: 05-Sep-2023
• Replaces: IEC 61158-4:2003/COR1:2004 - Corrigendum 1 - Digital data communications for measurement and control - Fieldbus for use in industrial control systems - Part 4: Data link protocol specification
• Effective Date: 05-Sep-2023
• Revised: IEC 61158-4-2:2010 - Industrial communication networks - Fieldbus specifications - Part 4-2: Application layer protocol specification - Type 2 elements
• Effective Date: 05-Sep-2023

Overview

IEC 61158-4-2:2007 is part of the IEC 61158 series of fieldbus standards and defines the data‑link layer protocol (Type 2 elements) for industrial communication networks. It specifies a deterministic, cyclic protocol that gives each participating data‑link entity communication opportunities in a sequential, cyclic manner. The protocol supports foreground scheduled access for time‑critical traffic and background unscheduled access for less critical traffic, and improves throughput by concatenating multiple DLSDUs and DLPCI into a single DLPDU.

This edition (2007) is a minor revision that cancels/replaces IEC 61158‑4:2003 and IEC/PAS 62413 (2005) and is presented in a bilingual (2014) version corresponding to the English 2007 release.

Key topics and technical requirements

• Media access model: Cyclic, sequential access with distinct scheduled (time‑critical) and unscheduled windows for mixed real‑time and non‑real‑time traffic.
• Efficiency mechanisms: Concatenation of multiple DLSDUs and DLPCI into a single DLPDU to optimize multi‑stream data transfers.
• DLPDU and Lpacket formats: Detailed structure and encoding rules for DLPDUs and multiple Lpacket types (generic tag, fixed tag, moderator, time distribution, UCMM, TUI, I’m‑alive, ping, IP/Ethernet Lpackets, etc.).
• Addressing: Definitions and encoding for DL addresses, MAC IDs, tag addressing schemes and group addressing.
• Station management objects: Specified objects and services for station management such as ControlNet, Keeper, Scheduling, TCP/IP Interface, Ethernet link, DeviceNet, and Connection Configuration (CCO).
• Operational procedures: Network attachment monitor (NAM), link parameter calculation, error and state machines, and conformance criteria.
• DLL component behavior: Access control machine (ACM), Tx/Rx LLC, transmit/receive machines, serializer/deserializer and DLL management functions.

Applications

IEC 61158-4-2 is applicable to industrial control and automation systems that require:

• Deterministic, time‑synchronized fieldbus communications
• Support for devices that source multiple data streams (PLCs, I/O modules, motion controllers)
• Mixed traffic types where strict timing is required for some messages but not for others
• Integration with Ethernet/TCP‑IP and other fieldbus layers via defined interface Lpackets and objects

Typical use cases include process control, discrete manufacturing, networked sensors/actuators and machine‑level real‑time communications.

Who should use this standard

• Fieldbus protocol designers and vendors
• Firmware and device manufacturers implementing Type 2 data‑link behavior
• System integrators and automation engineers specifying deterministic networks
• Test labs and certification bodies validating conformance to IEC 61158 data‑link requirements

Related standards

• IEC 61158 series (other parts for physical layer and higher protocol elements)
• IEC/PAS 62413 (replaced by this and companion parts)

Keywords: IEC 61158-4-2, fieldbus, data-link layer, DLPDU, DLSDU, deterministic communication, scheduled access, ControlNet, DeviceNet, industrial communication.

Standards Content (Sample)

IEC 61158-4-2
Edition 1.0 2007-12
INTERNATIONAL
STANDARD
Industrial communication networks – Fieldbus specifications –
Part 4-2: Data-link layer protocol specification – Type 2 elements

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IEC 61158-4-2
Edition 1.0 2007-12
INTERNATIONAL
STANDARD
Industrial communication networks – Fieldbus specifications –
Part 4-2: Data-link layer protocol specification – Type 2 elements

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
XH
ICS 35.100.20; 25.040.40 ISBN 2-8318-9428-X

– 2 – 61158-4-2 © IEC:2007(E)
CONTENTS
FOREWORD.7

INTRODUCTION.9

1 Scope.10

1.1 General .10

1.2 Specifications.10

1.3 Procedures.10

1.4 Applicability.11

1.5 Conformance.11
2 Normative references .11
3 Terms, definitions, symbols and abbreviations.12
3.1 Reference model terms and definitions.12
3.2 Service convention terms and definitions.14
3.3 Common terms and definitions .15
3.4 Additional Type 2 definitions.16
3.5 Type 2 symbols and abbreviations.23
4 Overview of the DL-protocol .24
4.1 General .24
4.2 Services provided by the DL.26
4.3 Structure and definition of DL-addresses.27
4.4 Services assumed from the PhL .29
4.5 Functional classes.31
5 General structure and encoding of PhIDUs and DLPDUs and related elements of
procedure.32
5.1 Overview .32
5.2 Media access procedure.32
5.3 DLPDU structure and encoding .35
5.4 Lpacket components .39
5.5 DLPDU procedures .41
5.6 Summary of DLL support services and objects .42
6 Specific DLPDU structure, encoding and procedures.44
6.1 Modeling language .44
6.2 DLS user services .46
6.3 Generic tag Lpacket .52
6.4 Moderator Lpacket .53
6.5 Time distribution Lpacket .54
6.6 UCMM Lpacket.57
6.7 Keeper UCMM Lpacket.57
6.8 TUI Lpacket.58
6.9 Link parameters Lpacket and tMinus Lpacket .59
6.10 I’m-alive Lpacket .60
6.11 Ping Lpackets.62
6.12 WAMI Lpacket .64
6.13 Debug Lpacket .64
6.14 IP Lpacket .65
6.15 Ethernet Lpacket .65
7 Objects for station management .65

61158-4-2 © IEC:2007(E) – 3 –
7.1 General .65

7.2 ControlNet object .66

7.3 Keeper object.76

7.4 Scheduling object.98

7.5 TCP/IP Interface object .109

7.6 Ethernet link object.118

7.7 DeviceNet object .124

7.8 Connection configuration object (CCO). 132

8 Other DLE elements of procedure. 152

8.1 Network attachment monitor (NAM) .152
8.2 Calculating link parameters .159
9 Detailed specification of DL components .167
9.1 General .167
9.2 Access control machine (ACM).167
9.3 TxLLC .184
9.4 RxLLC .188
9.5 Transmit machine (TxM).191
9.6 Receive machine (RxM) .194
9.7 Serializer.200
9.8 Deserializer .201
9.9 DLL management .202
Annex A (normative) Indicators and switches.205
A.1 Purpose .205
A.2 Indicators .205
A.3 Switches .216
Bibliography.218
INDEX .219

Figure 1 – Relationships of DLSAPs, DLSAP-addresses and group DL-addresses .15
Figure 2 – Data-link layer internal architecture.25
Figure 3 – Basic structure of a MAC ID address.27
Figure 4 – Basic structure of a generic tag address .27
Figure 5 – Basic structure of a fixed tag address .28
Figure 6 – M_symbols and Manchester encoding at 5 MHz (informative) .29

Figure 7 – NUT structure .33
Figure 8 – Media access during scheduled time.33
Figure 9 – Media access during unscheduled time .34
Figure 10 – DLPDU format.35
Figure 11 – Aborting a DLPDU during transmission .39
Figure 12 – Lpacket format .39
Figure 13 – Generic tag Lpacket format .40
Figure 14 – Fixed tag Lpacket format.41
Figure 15 – Goodness parameter of TimeDist_Lpacket .55
Figure 16 – Example I’m alive processing algorithm.62
Figure 17 – Keeper CRC algorithm .82
Figure 18 – Keeper object power-up state diagram .94

– 4 – 61158-4-2 © IEC:2007(E)
Figure 19 – Keeper object operating state diagram .95

Figure 20 – Synchronized network change processing .98

Figure 21 – State transition diagram for TCP/IP Interface object .118

Figure 22 – Connection configuration object edit flowchart. 152

Figure 23 – NAM state machine .153

Figure A.1 – Non redundant network status indicator labeling . 209

Figure A.2 – Redundant network status indicator labeling . 210

Table 1 – Data-link layer components .24
Table 2 – MAC ID addresses allocation .27
Table 3 – Fixed tag service definitions .28
Table 4 – Data encoding rules .29
Table 5 – M Data symbols .30
Table 6 – Truth table for ph_status_indication.31
Table 7 – FCS length, polynomials and constants .37
Table 8 – DLL support services and objects.43
Table 9 – Elementary data types.46
Table 10 – DLL events.51
Table 11 – Time distribution priority .56
Table 12 – Format of the TUI Lpacket .58
Table 13 – ControlNet object class attributes .67
Table 14 – ControlNet object instance attributes .67
Table 15 – TUI status flag bits .71
Table 16 – Channel state bits .72
Table 17 – ControlNet object common services.74
Table 18 – ControlNet object class specific services .75
Table 19 – Keeper object revision history .77
Table 20 – Keeper object class attributes .77
Table 21 – Keeper object instance attributes .77
Table 22 – Keeper operating state definitions .80
Table 23 – Port status flag bit definitions .80

Table 24 – TUI status flag bits .81
Table 25 – Keeper attributes.84
Table 26 – Memory requirements (in octets) for the Keeper attributes.84
Table 27 – Keeper object common services .85
Table 28 – Keeper object class specific services .86
Table 29 – Service error codes .87
Table 30 – Wire order format of the TUI Lpacket.91
Table 31 – Service error codes .92
Table 32 – Keeper object operating states .92
Table 33 – Keeper object state event matrix .96
Table 34 – Scheduling object class attributes .99
Table 35 – Scheduling object instance attributes .100

61158-4-2 © IEC:2007(E) – 5 –
Table 36 – Scheduling object common services . 100

Table 37 – Status error descriptions for Create.101

Table 38 – Status error descriptions for Delete and Kick_Timer .102

Table 39 – Scheduling object class specific services . 102

Table 40 – Status error descriptions for Read .104

Table 41 – Status error descriptions for Conditional_Write.105

Table 42 – Status error descriptions for Forced_Write . 105

Table 43 – Status error descriptions for Change_Start .106

Table 44 – Status error descriptions for Break_Connections . 106
Table 45 – Status error descriptions for Change_Complete. 107
Table 46 – Status error descriptions for Restart_Connections .108
Table 47 – TCP/IP Interface object class attributes.109
Table 48 – TCP/IP Interface object instance attributes. 110
Table 49 – Status bits .112
Table 50 – Configuration capability bits .112
Table 51 – Configuration control bits.113
Table 52 – Example path .113
Table 53 – Interface configuration components .114
Table 54 – Alloc control values .115
Table 55 – TCP/IP Interface object common services .116
Table 56 – Get_Attribute_All reply format .117
Table 57 – Ethernet link object revision history .118
Table 58 – Ethernet link object class attributes .119
Table 59 – Ethernet link object instance attributes . 119
Table 60 – Interface flags bits.121
Table 61 – Control bits.123
Table 62 – Ethernet Link object common services. 123
Table 63 – Ethernet Link object class specific services .124
Table 64 – DeviceNet object revision history.124
Table 65 – DeviceNet object class attributes.125
Table 66 – DeviceNet object instance attributes.125

Table 67 – Bit rate attribute values .127
Table 68 – BOI attribute values.128
Table 69 – Diagnostic counters bit description .129
Table 70 – DeviceNet object common services .130
Table 71 – Reset service parameter .130
Table 72 – Reset service parameter values .131
Table 73 – DeviceNet object class specific services. 131
Table 74 – Connection configuration object revision history .132
Table 75 – Connection configuration object class attributes . 132
Table 76 – Format number values.134
Table 77 – Connection configuration object instance attributes . 135
Table 78 – Originator connection status values.137

– 6 – 61158-4-2 © IEC:2007(E)
Table 79 – Target connection status values .138

Table 80 – Connection flags .138

Table 81 – I/O mapping formats .140

Table 82 – Connection configuration object common services. 141

Table 83 – Get_Attribute_All error codes .141

Table 84 – Get_Attribute_All response.142

Table 85 – Set_Attribute_All error codes.143

Table 86 – Set_Attribute_All request.144

Table 87 – Create request parameters.145
Table 88 – Create error codes .146
Table 89 – Delete error codes.146
Table 90 – Restore error codes.146
Table 91 – Connection configuration object class specific services . 147
Table 92 – Kick_Timer error codes .147
Table 93 – Open_Connection error codes .148
Table 94 – Close_Connection error codes .148
Table 95 – Stop_Connection error codes .148
Table 96 – Change_Start error codes .149
Table 97 – Get_Status service parameter .149
Table 98 – Get_Status service response.149
Table 99 – Get_Status service error codes .150
Table 100 – Change_Complete service parameter . 150
Table 101 – Change_Complete service error codes . 150
Table 102 – Audit_Changes service parameter .151
Table 103 – Audit_Changes service error codes . 151
Table 104 – NAM states.153
Table 105 – Default link parameters.154
Table 106 – PhL timing characteristics.160
Table A.1 – Module status indicator .206
Table A.2 – Network status indicators .207
Table A.3 – Network status indicator.211

Table A.4 – Network status indicator.213
Table A.5 – Combined module/network status indicator . 214
Table A.6 – I/O status indicator.215
Table A.7 – Bit rate switch encoding .217

61158-4-2 © IEC:2007(E) – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
INDUSTRIAL COMMUNICATION NETWORKS –

FIELDBUS SPECIFICATIONS –
Part 4-2: Data-link layer protocol specification – Type 2 elements

FOREWORD
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5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
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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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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.
NOTE  Use of some of the associated protocol types is restricted by their 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 particular data-link layer protocol type to be used with physical layer and application layer protocols in Type

combinations as specified explicitly in the IEC 61784 series. Use of the various protocol types in other
combinations may require permission from their respective intellectual-property-right holders.
IEC draws attention to the fact that it is claimed that compliance with this standard may involve the use of patents
as follows, where the [xx] notation indicates the holder of the patent right:
Type 2 and possibly other types:
US 5,400,331 [RA] Communication network interface with screeners for incoming messages
US 5,471,461 [RA] Digital communication network with a moderator station election process
US 5,491,531 [RA] Media access controller with a shared class message delivery capability
US 5,493,571 [RA] Apparatus and method for digital communications with improved delimiter
detection
US 5,537,549 [RA] Communication network with time coordinated station activity by time slot and
periodic interval number
US 5,553,095 [RA] Method and apparatus for exchanging different classes of data during different
time Intervals
IEC takes no position concerning the evidence, validity and scope of these patent rights.

– 8 – 61158-4-2 © IEC:2007(E)
The holders of these patent rights have assured 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. Information may be obtained from

[RA]: Rockwell Automation, Inc.
1201 S. Second Street
Milwaukee, WI 53204
USA
Attention: Intellectual Property Dept.

Attention is drawn to the possibility that some of the elements of this standard 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 61158-4-2 has been prepared by subcommittee 65C: Industrial

networks, of IEC technical committee 65: Industrial-process measurement, control and

automation.
This first edition and its companion parts of the IEC 61158-4 subseries cancel and replace
IEC 61158-4:2003. This edition of this part constitutes a minor revision. This part and its
companion Type 2 parts also cancel and replace IEC PAS 62413, published in 2005.
This edition of IEC 61158-4 includes the following significant changes from the previous
edition:
a) deletion of the former Type 6 fieldbus, and the placeholder for a Type 5 fieldbus data link
layer, for lack of market relevance;
b) addition of new types of fieldbuses;
c) division of this part into multiple parts numbered -4-1, -4-2, …, -4-19.
The text of this standard is based on the following documents:
FDIS Report on voting
65C/474/FDIS 65C/485/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 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.
NOTE  The revision of this standard will be synchronized with the other parts of the IEC 61158 series.
The list of all the parts of the IEC 61158 series, under the general title Industrial
communication networks – Fieldbus specifications, can be found on the IEC web site.

61158-4-2 © IEC:2007(E) – 9 –
INTRODUCTION
This part of IEC 61158 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/TR 61158-1.

The data-link protocol provides the data-link service by making use of the services available

from the physical layer. The primary aim of this standard is to provide a set of rules for

communication expressed in terms of the procedures to be carried out by peer data-link

entities (DLEs) at the time of communication. These rules for communication are intended to

provide a sound basis for development in order to serve a variety of purposes:

a) as a guide for implementors and designers;
b) for use in the testing and procurement of equipment;
c) as part of an agreement for the admittance of systems into the open systems environment;
d) as a refinement to the understanding of time-critical communications within OSI.
This standard is concerned, in particular, with the communication and interworking of sensors,
effectors and other automation devices. By using this standard together with other standards
positioned within the OSI or fieldbus reference models, otherwise incompatible systems may
work together in any combination.

– 10 – 61158-4-2 © IEC:2007(E)

INDUSTRIAL COMMUNICATION NETWORKS –

FIELDBUS SPECIFICATIONS –
Part 4-2: Data-link layer protocol specification – Type 2 elements

1 Scope
1.1 General
The data-link layer provides basic time-critical messaging communications between devices in
an automation environment.
This protocol provides communication opportunities to all participating data-link entities,
sequentially and in a cyclic synchronous manner. Foreground scheduled access is available
for time-critical activities together with background unscheduled access for less critical
activities.
Deterministic and synchronized transfers can be provided at cyclic intervals up to 1 ms and
device separations of 25 km. This performance is adjustable dynamically and on-line by re-
configuring the parameters of the local link whilst normal operation continues. By similar
means, DL connections and new devices may be added or removed during normal operation.
This protocol provides means to maintain clock synchronization across an extended link with
a precision better than 10 μs.
This protocol optimizes each access opportunity by concatenating multiple DLSDUs and
associated DLPCI into a single DLPDU, thereby improving data transfer efficiency for data-
link entities that actively source multiple streams of data.
The maximum system size is an unlimited number of links of 99 nodes, each with 255 DLSAP-
addresses. Each link has a maximum of 2 related peer and publisher DLCEPs.
1.2 Specifications
This standard specifies
a) procedures for the timely transfer of data and control information from one data-link user
entity to a peer user entity, and among the data-link entities forming the distributed data-
link service provider;
b) the structure of the fieldbus DLPDUs used for the transfer of data and control information
by the protocol of this standard, and their representation as physical interface data units.
1.3 Procedures
The procedures are defined in terms of
a) the interactions between peer DL-entities (DLEs) through the exchange of fieldbus
DLPDUs;
b) the interactions between a DL-service (DLS) provider and a DLS-user in the same system
through the exchange of DLS primitives;
c) the interactions between a DLS-provider and a Ph-service provider in the same system
through the exchange of Ph-service primitives.

61158-4-2 © IEC:2007(E) – 11 –

1.4 Applicability
These procedures are applicable to instances of communication between systems which

support time-critical communications services within the data-link layer of the OSI or fieldbus

reference models, and which require the ability to interconnect in an open systems

interconnection environment.
Profiles provide a simple multi-attribute means of summarizing an implementation’s

capabilities, and thus its applicability to various time-critical communications needs.

1.5 Conformance
This standard also specifies conformance requirements for systems implementing these
procedures. This standard does not contain tests to demonstrate compliance with such
requirements.
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 (Ed.4.0), Industrial communication networks – Fieldbus specifications – Part 2:
Physical layer specification and service definition
IEC 61158-3-2, Industrial communication networks – Fieldbus specifications – Part 3-2: Data-
link layer service definition – Type 2 elements
IEC 61158-5-2, Industrial communication networks – Fieldbus specifications – Part 5-2:
Application layer service definition – Type 2 elements
IEC 61158-6-2, Industrial communication networks – Fieldbus specifications – Part 6-2:
Application layer protocol specification – Type 2 elements
IEC 61784-3-2, Industrial communication networks – Profiles – Part 3-2: Functional safety
fieldbuses – Additional specifications for CPF 2
IEC 62026-3 , Low-voltage switchgear and controlgear – Controller-device interfaces (CDIs) –
Part 3: DeviceNet
ISO/IEC 3309, Information technology – Telecommunications and information exchange
between systems – High-level data link control (HDLC) procedures – Frame structure
ISO/IEC 7498-1, Information technology – Open Systems Interconnection – Basic Reference
Model: The Basic Model
ISO/IEC 7498-3, Information technology – Open Systems Interconnection – Basic Reference
Model: Naming and addressing
ISO/IEC 8802-3, Information technology – Telecommunications and information exchange
between systems – Local and metropolitan area networks – Specific requirements – Part 3:
Carrier sense multiple access with collision detection (CSMA/CD) access method and
physical layer specifications
To be published.
– 12 – 61158-4-2 © IEC:2007(E)

ISO/IEC 10731, Information technology – Open Systems Interconnection – Basic Reference

Model – Conventions for the definition of OSI services

ISO 11898:1993 , Road vehicles – Interchange of digital information – Controller area

network (CAN) for high-speed communication

3 Terms, definitions, symbols and abbreviations

For the purposes of this document, the following terms, definitions, symbols and abbreviations

apply.
3.1 Reference model terms and definitions
This standard is based in part on the concepts developed in ISO/IEC 7498-1 and ISO/IEC
7498-3, and makes use of the following terms defined therein.
3.1.1 called-DL-address [ISO/IEC 7498-3]
3.1.2 calling-DL-address
[ISO/IEC 7498-3]
3.1.3 centralized multi-end-point-connection [ISO/IEC 7498-1]
3.1.4 correspondent (N)-entities
[ISO/IEC 7498-1]
correspondent DL-entities  (N=2)
correspondent Ph-entities  (N=1)
3.1.5 demultiplexing [ISO/IEC 7498-1]
3.1.6 DL-address
[ISO/IEC 7498-3]
3.1.7 DL-address-mapping [ISO/IEC 7498-1]
3.1.8 DL-connection [ISO/IEC 7498-1]
3.1.9 DL-connection-end-point [ISO/IEC 7498-1]
3.1.10 DL-connection-end-point-identifier [ISO/IEC 7498-1]
3.1.11 DL-connection-mode transmission [ISO/IEC 7498-1]
3.1.12 DL-connectionless-mode transmission
[ISO/IEC 7498-1]
3.1.13 DL-data-sink [ISO/IEC 7498-1]

3.1.14 DL-data-source [ISO/IEC 7498-1]
3.1.15 DL-duplex-transmission [ISO/IEC 7498-1]
3.1.16 DL-facility [ISO/IEC 7498-1]
3.1.17 DL-local-view [ISO/IEC 7498-3]
3.1.18 DL-name [ISO/IEC 7498-3]
3.1.19 DL-protocol [ISO/IEC 7498-1]
3.1.20 DL-protocol-connection-identifier [ISO/IEC 7498-1]
3.1.21 DL-protocol-control-information [ISO/IEC 7498-1]

A newer edition of this standard has been published, but only the cited edition applies.

61158-4-2 © IEC:2007(E) – 13 –

3.1.22 DL-protocol-data-unit [ISO/IEC 7498-1]

3.1.23 DL-protocol-version-identifier [ISO/IEC 7498-1]

3.1.24 DL-relay
...

IEC 61158-4-2 ®
Edition 1.0 2007-12
INTERNATIONAL
STANDARD
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Industrial communication networks – Fieldbus specifications –
Part 4-2: Data-link layer protocol specification – Type 2 elements

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IEC 61158-4-2 ®
Edition 1.0 2007-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Industrial communication networks – Fieldbus specifications –

Part 4-2: Data-link layer protocol specification – Type 2 elements

Réseaux de communication industriels – Spécifications des bus de terrain –

Partie 4-2: Spécification du protocole de la couche liaison de données –

Éléments de Type 2
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XH
ICS 25.040.40; 35.100.20 ISBN 978-2-8322-1697-2

– 2 – IEC 61158-4-2:2007 © IEC 2007
CONTENTS
FOREWORD. 7
INTRODUCTION . 9
1 Scope . 10
1.1 General . 10
1.2 Specifications . 10
1.3 Proc edures . 10
1.4 Applicability . 11
1.5 Conformance . 11
2 Normative references . 11
3 Terms, definitions, symbols and abbreviations . 12
3.1 Reference model terms and definitions . 12
3.2 Service convention terms and definitions . 14
3.3 Common terms and definitions . 15
3.4 Additional Type 2 definitions . 16
3.5 Type 2 symbols and abbreviations . 23
4 Overview of the DL-protocol . 24
4.1 General . 24
4.2 Services provided by the DL . 26
4.3 Structure and definition of DL-addresses . 27
4.4 Services assumed from the PhL . 29
4.5 Functional classes . 31
5 General structure and encoding of PhIDUs and DLPDUs and related elements of
procedure . 32
5.1 Overview . 32
5.2 Media access procedure . 32
5.3 DLPDU structure and encoding . 35
5.4 Lpacket components . 39
5.5 DLPDU procedures . 41
5.6 Summary of DLL support services and objects . 42
6 Specific DLPDU structure, encoding and procedures . 44
6.1 Modeling language . 44
6.2 DLS user services . 46
6.3 Generic tag Lpacket . 52
6.4 Moderator Lpacket . 53
6.5 Time distribution Lpacket . 54
6.6 UCMM Lpacket . 57
6.7 Keeper UCMM Lpacket . 57
6.8 TUI Lpacke t . 58
6.9 Link parameters Lpacket and tMinus Lpacket . 59
6.10 I’m-alive Lpacket . 60
6.11 Ping Lpack e ts . 62
6.12 WAMI Lpacket . 64
6.13 Debug Lpacket . 64
6.14 IP Lpacket . 65
6.15 Ethernet Lpacket . 65
7 Objects for station management . 65

7.1 General . 65
7.2 ControlNet object . 66
7.3 Keeper object . 76
7.4 Scheduling object . 98
7.5 TCP/IP Interface object . 109
7.6 Ethernet link object . 118
7.7 DeviceNet object . 124
7.8 Connection configuration object (CCO) . 132
8 Other DLE elements of procedure . 152
8.1 Network attachment monitor (NAM) . 152
8.2 Calculating link parameters . 159
9 Detailed specification of DL components . 167
9.1 General . 167
9.2 Access control machine (ACM) . 167
9.3 TxLLC . 184
9.4 RxLLC . 188
9.5 Transmit machine (TxM) . 191
9.6 Receive machine (RxM) . 194
9.7 Serializer . 200
9.8 Deserializer . 201
9.9 DLL management . 202
Annex A (normative) Indicators and switches . 205
A.1 Purpose . 205
A.2 Indicators . 205
A.3 Switches . 216
Bibliography . 218
INDEX . 219

Figure 1 – Relationships of DLSAPs, DLSAP-addresses and group DL-addresses . 15
Figure 2 – Data-link layer internal architecture . 25
Figure 3 – Basic structure of a MAC ID address . 27
Figure 4 – Basic structure of a generic tag address . 27
Figure 5 – Basic structure of a fixed tag address . 28
Figure 6 – M_symbols and Manchester encoding at 5 MHz (informative) . 29
Figure 7 – NUT structure . 33
Figure 8 – Media access du ring sc heduled time . 33
Figure 9 – Media access during unscheduled time . 34
Figure 10 – DLPDU format . 35
Figure 11 – Aborting a DLPDU during transmission . 39
Figure 12 – Lpacket format . 39
Figure 13 – Generic tag Lpacket format . 40
Figure 14 – Fixed tag Lpacket format . 41
Figure 15 – Goodness parameter of TimeDist_Lpacket . 55
Figure 16 – Example I’m alive processing algorithm . 62
Figure 17 – Keeper CRC algorithm . 82
Figure 18 – Keeper object power-up state diagram . 94

– 4 – IEC 61158-4-2:2007 © IEC 2007
Figure 19 – Keeper object operating state diagram . 95
Figure 20 – Synchronized network change processing . 98
Figure 21 – State transition diagram for TCP/IP Interface object . 118
Figure 22 – Connection configuration object edit flowchart . 152
Figure 23 – NAM state machine . 153
Figure A.1 – Non redundant network status indicator labeling . 209
Figure A.2 – Redundant network status indicator labeling . 210

Table 1 – Data-link layer components . 24
Table 2 – MAC ID addresses allocation . 27
Table 3 – Fixed tag service defin itions. 28
Table 4 – Data encoding rules . 29
Table 5 – M Data symbols . 30
Table 6 – Truth table for ph_status_indication . 31
Table 7 – FCS length, polynomials and constants . 37
Table 8 – DLL support services and objects . 43
Table 9 – Elementary data types . 46
Table 10 – DLL events . 51
Table 11 – Time distribution priority . 56
Table 12 – Format of the TUI Lpacket . 58
Table 13 – ControlNet object class attributes . 67
Table 14 – ControlNet object instance attributes . 67
Table 15 – TUI status flag bits . 71
Table 16 – Channel state bits . 72
Table 17 – ControlNet object common services . 74
Table 18 – ControlNet object class specific services . 75
Table 19 – Keeper object revision history . 77
Table 20 – Keeper object class attributes . 77
Table 21 – Keeper object instance attributes . 77
Table 22 – Keeper operating state definitions . 80
Table 23 – Port status flag bit definitions . 80
Table 24 – TUI status flag bits . 81
Table 25 – Keeper attributes . 84
Table 26 – Memory requirements (in octets) for the Keeper attributes . 84
Table 27 – Keeper object common services . 85
Table 28 – Keeper object class specific services . 86
Table 29 – Service error codes . 87
Table 30 – Wire order format of the TUI Lpacket . 91
Table 31 – Service error codes . 92
Table 32 – Keeper object operating states . 92
Table 33 – Keeper object state event matrix . 96
Table 34 – Scheduling object class attributes . 99
Table 35 – Scheduling object instance attributes . 100

Table 36 – Scheduling object common services . 100
Table 37 – Status error descriptions for Create . 101
Table 38 – Status error descriptions for Delete and Kick_Timer . 102
Table 39 – Scheduling object class specific services . 102
Table 40 – Status error descriptions for Read . 104
Table 41 – Status error descriptions for Conditional_Write . 105
Table 42 – Status error descriptions for Forced_Write . 105
Table 43 – Status error descriptions for Change_Start . 106
Table 44 – Status error descriptions for Break_Connections . 106
Table 45 – Status error descriptions for Change _Complete . 107
Table 46 – Status error descriptions for Restart_Connections . 108
Table 47 – TCP/IP Interface object class attributes . 109
Table 48 – TCP/IP Interface object instance attributes . 110
Table 49 – Status bits . 112
Table 50 – Configuration capability bits . 112
Table 51 – Configuration control bits . 113
Table 52 – Example path . 113
Table 53 – Interface configuration components . 114
Table 54 – Alloc control values . 115
Table 55 – TCP/IP Interface object common services . 116
Table 56 – Get_Attribute_All reply format . 117
Table 57 – Ethernet link object revision history . 118
Table 58 – Ethernet link object class attributes . 119
Table 59 – Ethernet link object instance attributes . 119
Table 60 – Interface flags bits . 121
Table 61 – Control bi t s . 123
Table 62 – Ethernet Link object common services . 123
Table 63 – Ethernet Link object class specific services . 124
Table 64 – DeviceNet object revision history . 124
Table 65 – DeviceNet object class attributes . 125
Table 66 – DeviceNet object instance attributes . 125
Table 67 – Bit rate attribute values . 127
Table 68 – BOI attribute values . 128
Table 69 – Diagnostic counters bit description . 129
Table 70 – DeviceNet object common services . 130
Table 71 – Reset service parameter . 130
Table 72 – Reset service parameter values . 131
Table 73 – DeviceNet object class specific services. 131
Table 74 – Connection configuration object revision history . 132
Table 75 – Connection configuration object class attributes . 132
Table 76 – Format number values . 134
Table 77 – Connection configuration object instance attributes . 135
Table 78 – Originator connection status values . 137

– 6 – IEC 61158-4-2:2007 © IEC 2007
Table 79 – Target connection status values . 138
Table 80 – Connection flags . 138
Table 81 – I/O mapping formats . 140
Table 82 – Connection configuration object common services . 141
Table 83 – Get_Attribute_All error codes . 141
Table 84 – Get_Attribute_All response . 142
Table 85 – Set_Attribute_All error codes . 143
Table 86 – Set_Attribute_All request . 144
Table 87 – Create request parameters . 145
Table 88 – Create error codes . 146
Table 89 – Delete error codes . 146
Table 90 – Restore error codes . 146
Table 91 – Connection configuration object class specific services . 147
Table 92 – Kick_Timer error codes . 147
Table 93 – Open_Connection error codes . 148
Table 94 – Close_Connection error codes . 148
Table 95 – Stop_Connection error codes . 148
Table 96 – Change_Start error codes . 149
Table 97 – Get_Status service parameter . 149
Table 98 – Get_Status service response . 149
Table 99 – Get_Status service error codes . 150
Table 100 – Change_Complete service parameter . 150
Table 101 – Change_Complete service error codes . 150
Table 102 – Audit_Changes service parameter . 151
Table 103 – Audit_Changes service error codes . 151
Table 104 – NAM s tat es . 153
Table 105 – Default link parameters . 154
Table 106 – PhL timing characteristics . 160
Table A.1 – Module status indicator. 206
Table A.2 – Network status indicators . 207
Table A.3 – Network status indicator . 211
Table A.4 – Network status indicator . 213
Table A.5 – Combined module/network status indicator . 214
Table A.6 – I/O status indicator . 215
Table A.7 – Bit rate switch encoding. 217

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 4-2: Data-link layer protocol specification – Type 2 elements

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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5) IEC 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.
NOTE  Use of some of the associated protocol types is restricted by their 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 particular data-link layer protocol type to be used with physical layer and application layer protocols in Type
combinations as specified explicitly in the IEC 61784 series. Use of the various protocol types in other
combinations may require permission from their respective intellectual-property-right holders.
IEC draws attention to the fact that it is claimed that compliance with this standard may involve the use of patents
as follows, where the [xx] notation indicates the holder of the patent right:
Type 2 and possibly other types:
US 5,400,331 [RA] Communication network interface with screeners for incoming messages
US 5,471,461 [RA] Digital communication network with a moderator station election process
US 5,491,531 [RA] Media access controller with a shared class message delivery capability
US 5,493,571 [RA] Apparatus and method for digital communications with improved delimiter
detection
US 5,537,549 [RA] Communication network with time coordinated station activity by time slot and
periodic interval number
US 5,553,095 [RA] Method and apparatus for exchanging different classes of data during different
time Intervals
IEC takes no position concerning the evidence, validity and scope of these patent rights.

– 8 – IEC 61158-4-2:2007 © IEC 2007
The holders of these patent rights have assured 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. Information may be obtained from
[RA]: Rockwell Automation, Inc.
1201 S. Second Street
Milwaukee, WI 53204
USA
Attention: Intellectual Property Dept.
Attention is drawn to the possibility that some of the elements of this standard 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 61158-4-2 has been prepared by subcommittee 65C: Industrial
networks, of IEC technical committee 65: Industrial-process measurement, control and
automation.
This bilingual version (2014-07) corresponds to the English version, published in 2007-12.
This first edition and its companion parts of the IEC 61158-4 subseries cancel and replace
IEC 61158-4:2003. This edition of this part constitutes a minor revision. This part and its
companion Type 2 parts also cancel and replace IEC PAS 62413, published in 2005.
This edition of IEC 61158-4 includes the following significant changes from the previous
edition:
a) deletion of the former Type 6 fieldbus, and the placeholder for a Type 5 fieldbus data link
layer, for lack of market relevance;
b) addition of new types of fieldbuses;
c) division of this part into multiple parts numbered -4-1, -4-2, …, -4-19.
The text of this standard is based on the following documents:
FDIS Report on voting
65C/474/FDIS 65C/485/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 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.
NOTE  The revision of this standard will be synchronized with the other parts of the IEC 61158 series.
The list of all the parts of the IEC 61158 series, under the general title Industrial
communication networks – Fieldbus specifications, can be found on the IEC web site.

INTRODUCTION
This part of IEC 61158 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/TR 61158-1.
The data-link protocol provides the data-link service by making use of the services available
from the physical layer. The primary aim of this standard is to provide a set of rules for
communication expressed in terms of the procedures to be carried out by peer data-link
entities (DLEs) at the time of communication. These rules for communication are intended to
provide a sound basis for development in order to serve a variety of purposes:
a) as a guide for implementors and designers;
b) for use in the testing and procurement of equipment;
c) as part of an agreement for the admittance of systems into the open systems environment;
d) as a refinement to the understanding of time-critical communications within OSI.
This standard is concerned, in particular, with the communication and interworking of sensors,
effectors and other automation devices. By using this standard together with other standards
positioned within the OSI or fieldbus reference models, otherwise incompatible systems may
work together in any combination.

– 10 – IEC 61158-4-2:2007 © IEC 2007
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 4-2: Data-link layer protocol specification – Type 2 elements

1 Scope
1.1 General
The data-link layer provides basic time-critical messaging communications between devices in
an automation environment.
This protocol provides communication opportunities to all participating data-link entities,
sequentially and in a cyclic synchronous manner. Foreground scheduled access is available
for time-critical activities together with background unscheduled access for less critical
activities.
Deterministic and synchronized transfers can be provided at cyclic intervals up to 1 ms and
device separations of 25 km. This performance is adjustable dynamically and on-line by re-
configuring the parameters of the local link whilst normal operation continues. By similar
means, DL connections and new devices may be added or removed during normal operation.
This protocol provides means to maintain clock synchronization across an extended link with
a precision better than 10 s.
This protocol optimizes each access opportunity by concatenating multiple DLSDUs and
associated DLPCI into a single DLPDU, thereby improving data transfer efficiency for data-
link entities that actively source multiple streams of data.
The maximum system size is an unlimited number of links of 99 nodes, each with 255 DLSAP-
addresses. Each link has a maximum of 2 related peer and publisher DLCEPs.
1.2 Specifications
This standard specifies
a) procedures for the timely transfer of data and control information from one data-link user
entity to a peer user entity, and among the data-link entities forming the distributed data-
link service provider;
b) the structure of the fieldbus DLPDUs used for the transfer of data and control information
by the protocol of this standard, and their representation as physical interface data units.
1.3 Procedures
The procedures are defined in terms of
a) the interactions between peer DL-entities (DLEs) through the exchange of fieldbus
DLPDUs;
b) the interactions between a DL-service (DLS) provider and a DLS-user in the same system
through the exchange of DLS primitives;
c) the interactions between a DLS-provider and a Ph-service provider in the same system
through the exchange of Ph-service primitives.

1.4 Applicability
These procedures are applicable to instances of communication between systems which
support time-critical communications services within the data-link layer of the OSI or fieldbus
reference models, and which require the ability to interconnect in an open systems
interconnection environment.
Profiles provide a simple multi-attribute means of summarizing an implementation’s
capabilities, and thus its applicability to various time-critical communications needs.
1.5 Conformance
This standard also specifies conformance requirements for systems implementing these
procedures. This standard does not contain tests to demonstrate compliance with such
requirements.
2 Normative references
The following referenced documents are indispensable for th
...