ISO/PRF TS 21815-2

Earth-moving machinery -- Collision warning and avoidance

Engins de terrassement -- Avertissement et évitement de collision

General Information

• Status: Published
• ICS: 53.100 - Earth-moving machinery
• Technical Committee: ISO/TC 127/SC 2 - Safety, ergonomics and general requirements
• Drafting Committee: ISO/TC 127/SC 2/JWG 28 - Joint ISO/TC 127/SC 2 - ISO/TC 82 - ISO/TC 82/SC 8 - ISO/TC 195 - ISO/TC 195/SC 3 WG:Collision awareness and avoidance
• Parallel Committee: ISO/TC 82 - Mining

Standards Content (sample)

TECHNICAL ISO/TS
SPECIFICATION 21815-2
First edition
Earth-moving machinery — Collision
warning and avoidance —
Part 2:
On-board J1939 communication
interface
Engins de terrassement — Avertissement et évitement de collision —
Partie 2: Interface de communication embarquée
Member bodies are requested to consult relevant national interests in ISO/TC
82,ISO/TC 195,ISO/TC 82/SC 8 before casting their ballot to the e-Balloting
application.
PROOF/ÉPREUVE
Reference number
ISO/TS 21815-2:2021(E)
ISO 2021
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ISO/TS 21815-2:2021(E)
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© ISO 2021

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Published in Switzerland
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ISO/TS 21815-2:2021(E)
Contents Page

Foreword .......................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols and abbreviated terms ........................................................................................................................................................... 5

5 Logical interface .................................................................................................................................................................................................... 5

5.1 Logical groups .......................................................................................................................................................................................... 5

5.2 Negotiation ................................................................................................................................................................................................. 6

5.3 Initialisation .............................................................................................................................................................................................. 6

5.4 Operation ..................................................................................................................................................................................................... 6

6 Physical interface ................................................................................................................................................................................................. 7

6.1 General ........................................................................................................................................................................................................... 7

6.2 Machine connector .............................................................................................................................................................................. 7

6.3 CxD connector .......................................................................................................................................................................................... 8

6.4 Override switch ...................................................................................................................................................................................... 9

6.5 Physical layer ............................................................................................................................................................................................ 9

7 J1939 communication protocol .........................................................................................................................................................10

7.1 General ........................................................................................................................................................................................................10

7.2 PGN:CxD»machine status ............................................................................................................................................................11

7.2.1 General...................................................................................................................................................................................11

7.2.2 PGN description .............................................................................................................................................................12

7.2.3 SPN structure ...................................................................................................................................................................14

7.3 PGN:CxD»MachineCommand ..................................................................................................................................................37

7.3.1 General...................................................................................................................................................................................37

7.3.2 PGN description .............................................................................................................................................................37

7.3.3 SPN structure ...................................................................................................................................................................39

7.4 PGN:Machine»CxDr eply ...............................................................................................................................................................43

7.4.1 General...................................................................................................................................................................................43

7.4.2 PGN description .............................................................................................................................................................45

7.4.3 SPN structure ...................................................................................................................................................................46

7.5 PGN:Machine»CxDdata (PR OPULSION) .........................................................................................................................54

7.5.1 General...................................................................................................................................................................................54

7.5.2 PGN description .............................................................................................................................................................55

7.5.3 SPN structure ...................................................................................................................................................................56

7.5.4 PROPULSION subsystem ........................................................................................................................................57

7.6 PGN:Machine»CxDstatus .............................................................................................................................................................62

7.7 PGN:Machine»CxDcommand ...................................................................................................................................................62

7.8 PGN:CxD»MachineR eply ..............................................................................................................................................................63

7.9 PGN:CxD»MachineData .................................................................................................................................................................63

7.10 PGN:Time/ Date ...................................................................................................................................................................................63

8 Documentation ....................................................................................................................................................................................................64

8.1 Machine documentation ..............................................................................................................................................................64

8.2 System documentation..................................................................................................................................................................64

Annex A (informative) Communication sequences ............................................................................................................................65

Annex B (informative) Trust mechanisms ...................................................................................................................................................73

Annex C (informative) Implementation examples for override and standby modes ......................................79

Bibliography .............................................................................................................................................................................................................................81

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ISO/TS 21815-2:2021(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 127, Earth-moving machinery,

Subcommittee SC 2, Safety, ergonomics and general requirements.
A list of all parts in the ISO 21815 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/TS 21815-2:2021(E)
Introduction

The increasing use of detection systems and avoidance technology has been supporting operators to

safely operate machines in the field of mining and construction. At the same time, there are demands to

set standards for machines and systems detecting, alerting and intervening to mitigate collision risk.

There are currently two existing standards in the field: ISO 16001 and ISO 17757. These standards

provide guidance for visibility aids and object detection systems and for autonomous and semi-

autonomous machines, however, there is currently no standard that describes collision risk awareness,

warning signals and collision avoidance actions of the machinery operated by humans where there is a

risk of collision.

Collision warning and avoidance systems are developing technologies; and the algorithms are not yet

mature and well understood. This document is intended to foster innovation and accelerate the pace of

improvements in new collision warning and avoidance technologies. The performance requirements of

this document are technology neutral and do not specify technologies to meet the requirements.

The systems described in this document are intended to assist the operator of the machine. As current

technologies are unable to achieve full collision warning/avoidance in every situation, the responsibility

for safe operation of the machine remains with the operator of the machine.

This document defines a protocol for communication between a machine and a connected device to

allow the connected device to command the machine to slow down, stop or to maintain a stationary

state where the machine can move in a linear (i.e. forwards-backwards) direction along a travel path.

Machines with rotational movements (e.g. excavators) and machines with compound movements (e.g.

machines with booms) are only considered to the extent of the linear component of their travel.

The machine manufacturer may be flexible in deciding which method is most appropriate for their

machine. Some applications can be delivered with basic functionality (e.g. without the use of registers).

Regardless of which approach is selected, the connected device has a means to discover the capabilities

of the machine.

Annex B outlines a mechanism for establishing trust between the machine and the connected device

based on the exchange of certificates at the session layer as defined by the machine manufacturer.

The message structure for the session layer can be different to the message structure defined in this

document.

The specification of the J1939 protocol in this document does not preclude the development of other

communication interfaces that can support collision warning and avoidance functionality. At the time of

publishing this document, protocols have only been defined for SAE J1939 due to the general availability

of CAN 2.0 interfaces on machinery and devices providing collision warning and avoidance functions.

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TECHNICAL SPECIFICATION ISO/TS 21815-2:2021(E)
Earth-moving machinery — Collision warning and
avoidance —
Part 2:
On-board J1939 communication interface
1 Scope

This document describes the on-board J1939 communication interface between a connected device

and mobile machines for use in earth-moving, mining and road construction applications to enable

interventional collision avoidance actions defined in ISO 21815-1 based on the SAE J1939 protocol. This

interface is intended for use by a collision avoidance system (CAS) device integrated independently

from the original machine providing intervention signals to slow down, stop or prevent motion of the

machine. The protocol defined by this document can also be used to provide input information for a

collision warning system (CWS).

This document is not intended for plug-and-play implementation of CAS or CWS on the machine.

Additional details not fully described in this document can be negotiated by the CAS or CWS

manufacturer and the machine manufacturer to enable functionality.

This document does not preclude the possibility of the machine manufacturer or the CxD manufacturer

developing alternative on-board communication interfaces.
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 19014-3, Earth-moving machinery — Functional safety — Part 3: Environmental performance and test

requirements of electronic and electrical components used in safety-related parts of the control system

SAE J1939-15, Reduced Physical Layer, 250 kbits/sec, UN-Shielded Twisted Pair (UTP)

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
collision warning system
CWS

system which detects intended objects in the collision risk area, evaluates the collision risk level and

provides a warning to the operator
[SOURCE: ISO 21815-1:—, 3.8]
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ISO/TS 21815-2:2021(E)
3.2
collision avoidance system
CAS

system which detects intended objects in the collision risk area, evaluates the collision risk level and

provides interventional collision avoidance action (3.9)
[SOURCE: ISO 21815-1:—, 3.9]
3.3
CxS
CWS (3.1) or CAS (3.2) or both
[SOURCE: ISO 21815-1:—, 3.10]
3.4
CxS device
CxD
proximity detection system

device with sensors providing CxS (3.3) functions to detect objects in the proximity of the machine,

assess the collision risk level, warn the operator of the presence of object(s) for CWS (3.1), and/

or provide signals to the machine control system to initiate the appropriate interventional collision

avoidance action (3.9) on the machine for CAS (3.2)

Note 1 to entry: Proximity detection system (PDS) is a colloquial industry term for a physical device providing

CWS or CAS functionality.
3.5
on-board communication interface

bi-directional connection between a CxD (3.4) and the machine in a CWS (3.1) or CAS (3.2)

Note 1 to entry: The CxS (3.3) may utilise information sent from the machine via the on-board communication

interface to improve the estimation of the collision risk level. Only a CAS can initiate interventional collision

avoidance action (3.9) over the on-board communication interface.
3.6
register

storage location on the machine side of the on-board communication interface (3.5) that may be read and

optionally written to by the CxD (3.4)

Note 1 to entry: Changing the value of a register does not immediately initiate an interventional collision

avoidance action (3.9).
3.7
parameter
type of register (3.6) that is used to store configuration information
EXAMPLE Software revision, timeout, max speed for emergency stop.
3.8
setpoint

type of register (3.6) that is used by the machine to respond to an interventional collision avoidance

action (3.9)
EXAMPLE Minimum braking, maximum throttle, maximum speed.
3.9
action

message sent from the CxD (3.4) to the machine to change an internal register (3.6), or to initiate a

machine function
EXAMPLE Reduce speed, apply brakes, inhibit motion.
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ISO/TS 21815-2:2021(E)
3.10
enquiry

message sent from the CxD (3.4) to the machine to read an internal register (3.6), or request a machine

capabilityEXAMPLE Slow down, emergency stop, controlled stop.
3.11
instruction
action (3.9) or enquiry (3.10) issued by the CxD (3.4)
3.12
reply
response (3.35) of the machine to an instruction (3.11) from the CxD (3.4)
3.13
logical group

grouping of related information or instruction (3.11) elements into a coherent message, sent from the

CxD (3.4) to the machine or from the machine to the CxD over the on-board communication interface

(3.5)
3.14
+bat
system voltage of the machine as defined by the machine manufacturer
Note 1 to entry: Typical voltages are 12 V or 24 V DC.
3.15
key switch
device used by the operator to turn on or turn off the machine
3.16
isolator switch
disconnect switch

device used by the operator to isolate the batteries or electrical supply to the machine

3.17
+bat(switched)

machine system level voltage that is turned on or off through the key switch (3.15)

3.18
+bat(un-switched)

voltage that is not affected by the state of the key switch (3.15), but is affected by the isolator switch

(3.16)
3.19
CxD harness
auxiliary wiring between the machine connector and the CxD (3.4) connector
3.20
CxD bus

CAN-bus communication path between the machine and the CxD (3.4) terminated by 120 Ohm resistors

at each end
3.21
CxD branch
machine-to-CxD bus or CxD-to-CxD bus wiring connection
3.22
PowerOn()
startup sequence for the machine that enables CxD (3.4) operation
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ISO/TS 21815-2:2021(E)
3.23
doNegotiation()

automatic or semi-automatic process that verifies the credentials of the CxD (3.4) attached to the

machine and returns permissions for the CxD to send commands to the machine and receive machine

information
3.24
enableTimeout()

automatic process that enables an automatic timer that counts down to zero and sets a flag that there

has been a communications error on the J1939 on-board communication interface (3.5)

3.25
resetTimeout()

automatic process that resets the automatic timer and clears the error flag indicating that the J1939 on-

board communication interface (3.5) is functioning normally
3.26
doEmergencyStop()
automatic process that initiates an emergency stop on the machine
3.27
doControlledStop()
automatic process that initiates a controlled stop on the machine
3.28
doSlowDown()
automatic process that slows down the machine
3.29
doStandDown()
automatic process that brings the machine to a halted state
3.30
doBypassPropulsion()
instruction to bypass the propulsion system
3.31
doApplyPropulsionSetpoints()
activation of braking, throttle, speed setpoint (3.8) registers (3.6)
3.32
doMotionInhibit()
automatic process that prevents a machine from moving while stationary
3.33
doNormalOperation()

instruction (3.11) for the machine to continue with normal operation or return to normal operation

Note 1 to entry: This instruction has the effect of cancelling any other interventional collision avoidance action

(3.9) that is already in progress.
3.34
challenge

unique message issued by the machine to the CxD (3.4) to which a valid reply (3.12) is expected

3.35
response

reply (3.12) by the CxD (3.4) to the challenge (3.34) issued by the machine to establish trust

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ISO/TS 21815-2:2021(E)
4 Symbols and abbreviated terms
PGN parameter group number (see SAE J1939)
SPN suspect parameter number (see SAE J1939)
0xHH 8-bit hexadecimal value in the range 0x00 to 0xFF
0bB 1-bit binary value in the range 0b0 to 0b1
0bBB… N-bit binary value
5 Logical interface
5.1 Logical groups

The logical connections for the on-board J1939 communication interface between the CxD and the

machine are shown in Figure 1.
Figure 1 — Overview of logical CxD-machine interface
The logical groups defined for the on-board J1939 communication interface are:

— CxD»MachineStatus – this logical group of instructions allows the CxD to read or write to machine

registers and detect the health of the communication interface.

NOTE 1 This logical group is used to provide machine status information to the CxD and allow the CxD to

inspect and modify machine registers.

Information sent over this logical group may be sent at the maximum data rate supported by the

machine.

— CxD»MachineCommand – instructions sent by CxD to machine to confirm or activate machine functions

(e.g. slow down, stop, inhibit motion).

NOTE 2 This logical group is used to initiate interventional collision avoidance actions at the specified

broadcast rate (see 7.3).

— Machine»CxDreply – response of machine to instructions sent by the CxD over CxD»MachineStatus or

CxD»MachineCommand, which may include:
— successful execution of the instruction;
— an error was encountered while executing the instruction;
— the instruction is not supported by the machine.
The machine may limit the maximum data rate over the communication interface by
delaying the response.
— Machine»CxDdata – data provided by machine to the CxD.
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ISO/TS 21815-2:2021(E)

— Time/Date – information sent by machine to CxD or from CxD to machine to synchronise system

clocks (see 7.10)

The enquiries and actions within each of these logical groups are described more fully in 5.2 to 5.4.

5.2 Negotiation

A higher level of sequence of negotiation and credentials may be used to protect the machine against

access from an unauthorized CxD or connection of an unauthorised device to the interface. The

negotiation sequence may be independently developed by the machine manufacturer and CxD supplier

for exclusive use on a specific machine and may include:
— protocol version;
— machine model ID;
— machine generation / revision / series;
— other information defined by machine manufacturer and CxD manufacturer.

The CxD may pass credential information to the machine in a predefined sequence agreed between

the CxD manufacturer and the machine manufacturer. Basic authentication methods are described in

7.2.3.1 (refer to NEGOTIATE_NOP description in Table 8).

A mechanism for establishing trust between the machine and the CxD is described in Annex B.

The machine may refuse to reply to or acknowledge all other instructions until after the negotiation

sequence has been completed successfully.

Once negotiation has been successfully completed, the CxD shall send a PROTOCOL_NOP instruction

within the specified maximum interval to avoid a timeout of the communication link.

5.3 Initialisation

After successful completion of the negotiation sequence, the CxD should read the contents of all

registers defined on the machine and discover the capabilities of the machine using the mechanisms

described in 7.2.

The CxD may read or write to registers after startup of the machine or at any time while the machine is

running.
5.4 Operation

After negotiation and initialisation have been completed, the CxD may initiate interventional collision

avoidance actions which are supported by the machine, including:
— motion inhibit;
— emergency stop;
— controlled stop;
— slow down;
— stand down;
— bypass propulsion;
— apply propulsion setpoints;
— no operation (NOP) – do nothing.
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ISO/TS 21815-2:2021(E)

The machine may not support all interventional collision avoidance actions listed here. The CxD should

discover the capabilities of the machine during initialisation.

Some interventional collision avoidance actions may require pre-conditions to be met, e.g. the machine

is stationary before motion inhibit is applied, maximum machine speed for emergency stop, valid

setpoint values provided by CxD.

Examples are shown for the PROPULSION subsystem only. Additional interventional collision avoidance

actions may be defined in other subsystems.
6 Physical interface
6.1 General
The connection between the machine and the CxD is defined in 6.2 to 6.5.

The connectors specified in 6.2 to 6.5 can be unsuitable for the specific requirements of machines

working in hazardous atmospheres. Alternative connector and connection arrangements may be used

in these cases.
6.2 Machine connector

The physical connector on the machine shall be Deutsch DT-Series 12-pin plug part DT06-12SC-EP06

(Key C) shown in Figure 2 or equivalent . The pin connections and pin definitions are shown in Table 1.

Dimensions in millimetres (inches)

Figure 2 — Machine physical connector - Deutsch DT-series 12 pin, part DT06-12SC-EP06

(Key C)
Table 1 — Machine pin connections
Pin Machine Comment
1 n/a Reserved f
...