ISO 16844-4:2022
(Main)Road vehicles — Tachograph systems — Part 4: Display unit communication interface
Road vehicles — Tachograph systems — Part 4: Display unit communication interface
This document specifies the CAN-based data communication between the display unit and other devices connected to an SAE J1939-based in-vehicle network. The provided requirements and recommendations cover physical, data link, network, and application layers according to the OSI reference model. Additionally, it specifies the parameter groups, which are supported.
Véhicules routiers — Systèmes tachygraphes — Partie 4: Interface de communication de l'unité d'affichage
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 16844-4
Third edition
2022-02
Road vehicles — Tachograph
systems —
Part 4:
Display unit communication interface
Véhicules routiers — Systèmes tachygraphes —
Partie 4: Interface de communication de l'unité d'affichage
Reference number
ISO 16844-4:2022(E)
© ISO 2022
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ISO 16844-4:2022(E)
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© ISO 2022
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ISO 16844-4:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms.2
5 CAN physical layer requirements .3
5.1 General . 3
5.2 CAN bit-timing requirements . 3
5.2.1 General . 3
5.2.2 CAN bit-timing requirements for 250 kbit/s . 3
5.2.3 CAN bit-timing requirements for 500 kbit/s . 4
6 CAN data link layer requirements.4
7 Transport layer requirements . 4
8 Application layer . 4
8.1 General requirements and permissions. 4
8.2 RQST — Request message . 5
8.3 ACKM — Acknowledgement message . 5
8.4 TD — Time/date . 6
8.5 VI — Vehicle identification . 6
8.6 VDHR — High-resolution vehicle distance . 6
8.7 SERV — Service information . 6
8.8 RESET — Reset . 6
8.9 TCO1 — Tachograph . 7
8.10 DI — Driver's identification . 7
8.11 TDA — Time/date adjust . 8
8.12 EEC1 — Electronic engine controller 1 . 8
9 Optional parameter groups . .9
9.1 CL — Cab illumination message . 9
9.2 Driving and rest times driver 1/2 – DRTD1/2 . 9
9.2.1 DRTD1 — Driver 1 driving rest times . 9
9.2.2 DRTD2 — Driver 2 driving rest times . 10
10 Recommended source address (SA) assignments .10
Bibliography .12
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ISO 16844-4:2022(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 31,
Data communication.
This third edition cancels and replaces the second edition (ISO 16844-4:2015), which has been
technically revised.
The main changes are as follows:
— part 5 of this series (ISO 16844-5) has been removed due to its technical irrelevance,
— correction of the typos and mistakes in the text,
— adoption of the content according to the new version of the ISO guidelines,
— adoption of the content according to the new technical requirements,
— alignment of the content regarding to the referred standards.
A list of all parts in the ISO 16844 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
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ISO 16844-4:2022(E)
Introduction
This document supports and facilitates the communication between electronic control units (ECUs)
and a digital tachograph.
The digital tachograph concept is based upon a recording equipment storing data, related to the
activities of the various drivers driving the vehicle, on which it is installed.
During the normal operational status of the recording equipment, data stored in its memory are
accessible to different entities (drivers, authorities, workshops, transport companies) in different ways
(displayed on a screen, printed by a printing device, downloaded to an external device). Access to stored
data is controlled by a smart card inserted in the tachograph.
A typical tachograph system is shown in Figure 1.
Key
1 data and service IF connector standardized in 4 CAN-based data IF including parameter groups
ISO 16844-1 standardized in this document
2 electrical data and service IF requirements 5 optional CAN-based service IF standardized in
standardized in ISO 16844-2 ISO 16844-6
3 communication interface between motion sensor 6 data identifier (DID) specification for the optional
and RE standardized in ISO 16844-3 service IF standardized in ISO 16844-7
Figure 1 — Typical ISO 16844-conformant tachograph system
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INTERNATIONAL STANDARD ISO 16844-4:2022(E)
Road vehicles — Tachograph systems —
Part 4:
Display unit communication interface
1 Scope
This document specifies the CAN-based data communication between the display unit and other devices
connected to an SAE J1939-based in-vehicle network. The provided requirements and recommendations
cover physical, data link, network, and application layers according to the OSI reference model.
Additionally, it specifies the parameter groups, which are supported.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 11898-1, Road vehicles — Controller area network (CAN) — Part 1: Data link layer and physical
signalling
ISO 16844-1, Road vehicles — Tachograph systems — Part 1: Recording equipment data and service
connector
ISO 16844-7, Road vehicles — Tachograph systems — Part 7: Parameters
SAE J1939-11, Physical Layer-250K bits/s, Twisted Shielded Pair
SAE J1939-14, Physical Layer, 500 Kbps
1)
SAE J1939-21, Data Link Layer
SAE J1939-71, Vehicle Application Layer
SAE J1939DA, Digital Annex
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 16844-1 and the following
apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
visual instrument
speedometer and display(s) for odometer and trip meter data
1) SAE does not use the terminology of the OSI reference model: the application and transport layer is named data
link layer (SAE J1939/21) and the parameter value specification is named vehicle application layer (SAE J1939/71).
The parameter specifications are provided in SAE J1939DA.
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ISO 16844-4:2022(E)
4 Symbols and abbreviated terms
For the purposes of this document, the following the following symbols and abbreviated terms apply.
ACK positive acknowledge
BAM broadcast announce message
CAN controller area network
DA destination address
DP data page
ECU electronic control unit
EDP extended data page
EOL end-of-line
LSB least significant bit/byte
MSB most significant bit/byte
NACK negative acknowledge
OSI open systems interconnection
P priority
PDU protocol data unit
PF PDU format
PG parameter group
PGN parameter group number
Phase_Seg1 phase buffer segment 1
Phase_Seg2 phase buffer segment 2
Prop_Seg propagation time segment
PS PDU specific
RE recording equipment
SA source address
Sync_Seg synchronization segment
TP.DT transport protocol data transfer
t
bit time
BIT
t
time quanta
q
t
timing segment 1
SEG1
t
timing segment 2
SEG2
2
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ISO 16844-4:2022(E)
t
synchronization jump width
SJW
VIN vehicle identification number
5 CAN physical layer requirements
5.1 General
The CAN physical layer interface shall meet the requirements of SAE J1939-11 and SAE J1939-14 unless
otherwise specified in this document. The CAN cabling and termination is not in the scope of this
document.
5.2 CAN bit-timing requirements
5.2.1 General
Figure 2 shows the terms used in this document and those defined in ISO 11898-1. According to
ISO 11898-1 the t has the length of 1 t .
Sync_Seg q
Key
1 ISO 11898 terms
2 ISO 16844 terms
3 sample-point
a
Nominal bit-time.
Figure 2 — Partition of bit time
For both specified bit-rates, 250 kbit/s and 500 kbit/s, the single sampling mode shall be used. The
sample-point shall be between 80
...
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