ISO 16844-4:2004

Road vehicles — Tachograph systems — Part 4: CAN interface

ISO 16844-4:2004 specifies the CAN (controller area network) interface for the interchange -- performed in accordance ISO 16844-6 -- of digital information between a road vehicle's tachograph system and vehicle units, and within the tachograph system itself. It specifies parameters of, and requirements for, the physical and data link layers of the electrical connection used in the electronic systems.

Véhicules routiers — Systèmes tachygraphes — Partie 4: Interface CAN

General Information

• Status: Withdrawn
• Publication Date: 06-Sep-2004
• Withdrawal Date: 06-Sep-2004
• ICS: 43.040.10 - Electrical and electronic equipment
• Technical Committee: ISO/TC 22/SC 31 - Data communication
• Drafting Committee: ISO/TC 22/SC 31/WG 4 - Network applications
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 13-Jan-2015

Relations

• Revised: ISO 16844-4:2015 - Road vehicles — Tachograph systems — Part 4: CAN interface
• Effective Date: 04-Sep-2010

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 16844-4
First edition
2004-09-01

Road vehicles — Tachograph systems —
Part 4:
CAN interface
Véhicules routiers — Systèmes tachygraphes —
Partie 4: Interface CAN




Reference number
ISO 16844-4:2004(E)
©
ISO 2004

---------------------- Page: 1 ----------------------
ISO 16844-4:2004(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.


©  ISO 2004
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland

ii © ISO 2004 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 16844-4:2004(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references. 1
3 Terms and definitions. 1
4 Abbreviated terms. 2
5 Physical layer. 3
5.1 General. 3
5.2 Bit timing requirements. 3
6 Data link layer. 4
6.1 Message frame format. 4
6.1.1 General. 4
6.1.2 P bits. 4
6.1.3 R bit. 5
6.1.4 DP bit. 5
6.1.5 PF field. 5
6.1.6 PS field. 5
6.1.7 SA field. 5
6.1.8 Data field. 5
6.2 PGN. 5
6.2.1 General. 5
6.2.2 PDU 1 format . 6
6.2.3 PDU 2 format . 6
6.3 Communication modes. 6
6.3.1 Request and acknowledge. 6
6.4 Transport protocol. 8
6.4.1 General. 8
6.4.2 BAM. 8
6.4.3 TP.DT. 8
7 Application layer. 9
7.1 General. 9
7.2 Time/Date. 9
7.3 Vehicle identification. 10
7.4 High resolution vehicle distance. 11
7.5 Service. 11
7.6 Reset. 12
7.7 TCO1. 13
7.8 Driver identification. 14
7.9 Time/date adjust. 15
7.10 EEC1. 16
7.11 Illumination. 17
8 Addresses. 17
Bibliography . 18

© ISO 2004 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO 16844-4:2004(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 16844-4 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 3,
Electrical and electronic equipment.
ISO 16844 consists of the following parts, under the general title Road vehicles — Tachograph systems:
 Part 1: Electrical connector
 Part 2: Recording unit, electrical interface
 Part 3: Motion sensor interface
 Part 4: CAN interface
 Part 5: Secured CAN interface
 Part 6: Diagnostics
 Part 7: Parameters
iv © ISO 2004 – All rights reserved

---------------------- Page: 4 ----------------------
ISO 16844-4:2004(E)
Introduction
ISO 16844 supports and facilitates the communication between electronic units and a tachograph; the
[1] [2]
tachograph being based upon Council Regulations (EEC) No. 3820/85 and (EEC) No. 3821/85 and their
[3] [4]
amendments Council Regulation (EEC) No. 2135/98 and Commission Regulation (EC) No. 1360/2002 .
Its purpose is to ensure the compatibility of tachographs from various tachograph manufacturers.
The basis of the digital tachograph concept is a recording unit (RU) that stores data related to the activities of
the drivers of a vehicle on which it is installed. When the RU is in normal operational status, the data stored in
its memory are made accessible to various entities such as drivers, authorities, workshops and transport
companies in a variety of ways: they may be displayed on a screen, printed by a printing device or
downloaded to an external device. Access to stored data is controlled by a smart card inserted in the
tachograph.
In order to prevent manipulation of the tachograph system, the speed signal sender (motion sensor) is
provided with an encrypted data link.
A typical tachograph system is shown in Figure 1.

Key
1 positive supply
2 battery minus
3 speed signal, real time
4 data signal in/out
Figure 1 — Typical tachograph system
© ISO 2004 – All rights reserved v

---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 16844-4:2004(E)

Road vehicles — Tachograph systems —
Part 4:
CAN interface
1 Scope
This part of ISO 16844 specifies the CAN (controller area network) interface for the interchange — performed
in accordance ISO 16844-6 — of digital information between a road vehicle's tachograph system and vehicle
units, and within the tachograph system itself. It specifies parameters of, and requirements for, the physical
and data link layers of the electrical connection used in the electronic systems.
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.
ISO 11898 (all parts), Road vehicles — Controller area network (CAN)
ISO 16844-6, Road vehicles — Tachograph systems — Part 6: Diagnostics
ISO 16844-7, Road vehicles — Tachograph systems — Part 7: Parameters
SAE J1939, Recommended Practice for a Serial Control and Communications Vehicle Network
SAE J1939/11, Physical Layer — 250 kbits/s, Twisted Shielded Pair
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
recording unit
part of the tachograph system that acquires and stores data concerning the vehicle and its driver(s) and their
activities
3.2
visual instrument
speedometer and display(s) for odometer and trip meter data
© ISO 2004 – All rights reserved 1

---------------------- Page: 6 ----------------------
ISO 16844-4:2004(E)
4 Abbreviated terms
ACK positive acknowledgement Phase_Seg1 phase segment 1
BAM broadcast announce message Phase_Seg2 phase segment 2
CAN controller area network PS PDU specific
DA destination address R reserved
DP data page RU recording unit
ECU electronic control unit SA source address
EEC1 electronic engine controller No. 1 Sync_Seg synchronization segment
EOL end of line TBD to be defined
GE group extension TP.DT transport protocol data transfer
LSB least significant bit t bit time
B
MSB most significant bit t time quanta
Q
NACK negative acknowledgement t timing segment 1
SEG1
P priority t timing segment 2
SEG2
PDU protocol data unit t synchronization jump width
SJW
PF PDU format t synchronization segment
SYNC_SEG
PGN parameter group number VIN vehicle identification number

2 © ISO 2004 – All rights reserved

---------------------- Page: 7 ----------------------
ISO 16844-4:2004(E)
5 Physical layer
5.1 General
The physical layer shall be in accordance with SAE J1939/11, except where otherwise specified in this part of
ISO 16844.
5.2 Bit timing requirements
The following parameters of CAN bit timing values shall be used for the settings of the tachograph ECUs (see
Figure 2), which shall be in accordance with Table 1.
t

SJW
t

B
t
Q
t = Sync_Seg = 1t

SYNCSEG Q
t = Prop_Seg + Phase_Seg1

SEG1
t = Phase_Seg2

SEG2

a
Nominal bit time.
Figure 2 — Partition of bit time
Table 1 — CAN bit timing parameter values — Single data sampling mode
Timing setting
Parameter
min. nominal max.
t
3 980 ns 4 000 ns 4 020 ns
B
t
— — 400 ns
Q
t t = t − 1t − t t = t − 1t − t t = t − 1t − t
SEG1 SEG1 B Q SEG2 SEG1 B Q SEG2 SEG1 B Q SEG2

© ISO 2004 – All rights reserved 3

---------------------- Page: 8 ----------------------
ISO 16844-4:2004(E)
The CAN bit timing values shall also be in accordance with the following conditions:
 nominal bit rate of 250 kBit/s ± 0,5 %;
 sample point at between 80 % and 88 % of nominal bit time, single data sampling mode.
Values for the bit timing shall be in accordance with Table 2, which base on time quanta t .
Q
Table 2 — CAN bit timing parameter values for standard time quanta
t t t
Q SJW SEG2
200 ns 600 ns 600 ns
250 ns 500 ns 750 ns
334 ns 668 ns 668 ns
400 ns 800 ns 800 ns
6 Data link layer
6.1 Message frame format
6.1.1 General
For the data link layer, the application layer provides a string of information that is assimilated into a PDU. The
PDU provides a framework for organizing the information, which shall be sent in the CAN data frame.
The 29 bit identifier shall be in accordance with ISO 11898.
The PDU shall consist of seven fields in addition to the specific CAN fields specified in Figure 3.
The PDU fields shall contain P, R, DP, PF, PS, which may be a DA or a GE, SA and data field.
P R DP PF PS SA Data field
Number of bi
...