ISO 23316-6:2024

International
Standard
ISO 23316-6
First edition
Tractors and machinery for
2024-01
agriculture and forestry —
Electrical high-power interface 700
V DC / 480 V AC —
Part 6:
Communication signals
Tracteurs et matériels agricoles et forestiers — Interface
électrique haute puissance 700VDC/480VAC —
Partie 6: Signaux de communication
Reference number
© ISO 2024
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Voltage classes . 3
5 General system overview . 4
5.1 General .4
5.2 Basic AC-system topology .4
5.3 Basic DC-system topology .6
6 Communication process and system handshake . 7
6.1 System handshake phases .7
6.2 Conditions for system handshake .8
6.3 HPI connection status monitoring .8
6.4 Interaction with TIM function state machine .9
7 Fieldbus . .13
8 HPI interlock function .13
8.1 Functional requirements . 13
8.2 Functional principle .14
9 Fieldbus-based system .15
9.1 Identification sequence using fieldbus . 15
9.2 Initialization sequence using fieldbus .17
9.3 Normal operation sequence using fieldbus .19
9.4 Sequence definition for normal system shutdown using fieldbus . 20
10 IL-based system .21
10.1 Identification and initialization of an IL-based system .21
10.1.1 General .21
10.1.2 CS identification of an IL-based system . 22
10.1.3 Identification procedure . 22
10.1.4 Additional conditions . 22
10.2 Determining the topology of the VC-B2 network of an IL-based system .24
10.3 System Initialization of an IL-based system .24
10.3.1 General .24
10.3.2 System handshake of an IL-based system . 26
10.4 Sequence definition for normal start-up of an IL-based system . 26
10.5 Sequence definition for normal system shutdown of an IL-based system . 28
10.6 Sequence diagrams for system handshake of an IL-based system . 29
11 Isolation resistance and insulation monitoring .33
11.1 General . 33
11.2 Communication . 34
11.2.1 General . 34
11.2.2 OIM initialization . 34
11.2.3 Minimum isolation resistance initialization . 34
11.2.4 Isolation resistance online measurement (operation of the completed system) . 36
Annex A (normative) Communication signals . .38
Annex B (informative) ISOBUS messages and message sets .85
Annex C (informative) Example for determining the topology of the network .87
Annex D (informative) Diagnostic trouble codes .89

iii
Annex E (informative) Example: Isolation resistance and insulation monitoring .92
Bibliography .94

iv
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 23, Tractors and machinery for agriculture and
forestry, Subcommittee SC 19, Agricultural electronics.
The document is intended to be used in conjunction with the ISO 11783 series and the other parts of
ISO 23316.
A list of all parts in the ISO 23316 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.

v
Introduction
Due to the requirements of modern agriculture, the precise control of implement functions is a key issue in
agricultural technology. The required precision is difficult to achieve with mechanical or hydraulic devices;
it is more efficient to provide control with electric and electronic means, i.e. electric power and ISOBUS. The
use of electric power allows implement manufacturers to offer farmers improved implements that provide
a higher degree of automation and navigation, resulting in greater precision, better power distribution, and
better controllability.
The purpose of the ISO 23316 series is to provide a design and application standard covering implementation
of electrical high-power interfaces operating with a nominal voltage of 700 V DC/480 V AC for manufacturers
of agricultural machinery.
The ISO 23316 series specifies the physical and logical interface requirements that provide interoperability
and cross compatibility for systems and equipment.
Conformance to the ISO 23316 series means all applicable requirements from ISO 23316-1 to ISO 23316-7
are met.
It is permitted for partial systems or components to conform to the ISO 23316 series by applying all
applicable requirements, for example, for the plug, receptacle, or inverters, on a tractor or an implement.
NOTE 1 If a DC-mode only HPI is provided, it is not necessary to conform with ISO 23316-4 which describes AC-
mode, as it is not applicable. If an AC-mode only HPI is provided, it is not necessary to conform with ISO 23316-5 which
describes DC-mode, as it is not applicable.
The ISO 23316 series defines an interface between a power providing device (supply system) and a power
consuming device (consumer system), used within an automated electrified system in the agricultural
industry. This series deals with electrical, mechanical and bus communication objectives and is used in
conjunction with ISO 11783, which defines the ISOBUS. Figure 1 portrays the elements of typical equipment
that involve the high-power interface.
The following aspects are not within the scope of ISO 23316:
— service, maintenance, and related diagnostics;
— functional safety;
— control strategies for high-power supplies and loads;
— application-specific strategies and operational modes;
— component design;
— energy storage systems, e. g. supercapacitors or batteries;
— multiple electrical power supplies to a common DC link.
NOTE 2 Annex D lists some basic diagnostics by DTCs.
NOTE 3 For example, AEF guideline 007 handles some aspects of functional safety already.

vi
Key
Symbol Description Symbol Description
APP application 1 high-power interface
PC/S power converter/switch 2 ISOBUS connector
HPI-C high-power interface - control 3 power lines
HPI-MC high-power interface - master control 4 ISOBUS
VT virtual terminal (user interface) power connection
I supply system signal connection
II consumer system
Figure 1 — Typical elements of system incorporating a high-power interface

vii
International Standard ISO 23316-6:2024(en)
Tractors and machinery for agriculture and forestry —
Electrical high-power interface 700 V DC / 480 V AC —
Part 6:
Communication signals
1 Scope
This document specifies the communication interface, so that the transmitted parameters, signals and
objects between a supply system (SS), with power converter/switch (PC/S) and high power interface –
master control (HPI-MC) including the tractor implement management (TIM) server, and a consumer system
(CS), with application (APP) and high power interface – control (HPI-C) including the TIM client and the task
controller, can be used is in the agricultural industry. The mentioned signals are used during identification,
initialization, operation, and shutdown modes of operation.
This document does not cover the definitions of suspect parameter numbers (SPNs) for the signals, within
the parameter group numbers (PGNs) for messages and the message setup. These definitions are given in
ISO 11783 and SAE J1939.
NOTE For information on messages (PGNs) see also Annex B.
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 16230-1:2015, Agricultural machinery and tractors — Safety of higher voltage electrical and electronic
components and systems — Part 1: General requirements
ISO 23316-1, Tractors and machinery for agriculture and forestry — Electrical high-power interface 700 V DC /
480 V AC — Part 1: General description
ISO 23316-2, Tractors and machinery for agriculture and forestry — Electrical high-power interface 700 V DC /
480 V AC — Part 2: Physical layer
ISO 23316-4:2023, Tractors and machinery for agriculture and forestry — Electrical high-power interface 700 V
DC / 480 V AC — Part 4: AC operation mode
ISO 23316-5:2023, Tractors and machinery for agriculture and forestry — Electrical high-power interface 700 V
DC / 480 V AC — Part 5: DC operation mode
ISO 23316-7, Tractors and machinery for agriculture and forestry — Electrical high-power interface 700 V DC /
480 V AC — Part 7: Mechanical integration
ISO 11783 (all parts), Tractors and machinery for agriculture and forestry — Serial control and communications
data network
IEC 60204:2016, Safety of machinery — Electrical equipment of machines
SAE J1939DA, Serial Control and Communications Heavy Duty Vehicle Network — Digital Annex

3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 23316-1, ISO 23316-2, ISO 23316-4,
ISO 23316-5, ISO 23316-7 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
direction of rotation
positive values for frequency or speed related to powering the power converter phases in the sequence U V
W positive torque means torque in the direction of positive speed
Note 1 to entry: If not stated otherwise (e.g. ground speed), the term ‘speed’ within this document refers always to
rotational movement.
3.2
fieldbus maindevice
device integrated within inverter onboard supply system, controls actively the communication within the
fieldbus network and requests/receives data to/from the fieldbus subdevice ((3.3), subordinated controller)
in a cyclically and time-wise deterministic manner
3.3
fieldbus subdevice
device integrated within LLB on-board consumer system receives data (e.g. requests) from and provides
data (e.g. feedback) to the fieldbus maindevice (3.2) passively
3.4
insulation monitor
IM
device monitoring the ungrounded system between an active phase conductor and the equipotential bonding
3.5
power converter/switch control
PC/S-C
control for AC mode, a power converter; for DC mode, a switch such as a contactor or solid-state switch,
typically an integral part of the PC/S-C
3.6
minimum isolation resistance
MIR
value in failure free condition but at worst case ambient conditions (considering humidity, fluids, cooling
type, etc. in operation)
3.7
multi consumer system
MCS
system of more than one consumer systems or consumer system trains, connected to the HPI in any
combination of a series or parallel configuration
3.8
online insulation monitor
OIM
system to measure the overall system isolation resistance onboard of the initial supply system

3.9
parameter group number
PGN
3-byte CAN Message, 24 bit, representation of the extended data page, data page, protocol data unit (PDU)
format, and group extension (GE) fields
[SOURCE: ISO 11783-1:2017, 3.44]
Note 1 to entry: The parameter group number uniquely identifies a particular parameter group.
3.10
pre-charge procedure
capacitor charging procedure to balance different DC link voltage levels
3.11
pre- and discharge unit
unit to pre- or discharge the DC link connected via HPI, typically an integral part of the PC/S-C
3.12
supply system master
SS-M
supply system that includes the initial power source, such as generator/rectifier unit or fuel cell, commonly
the tractor, typically the HPI-MC also resides there.
3.13
suspect parameter number
SPN
19-bit number used to identify a particular element, component, or parameter associated with a control
function
[SOURCE: ISO 11783-1:2017, 3.58]
Note 1 to entry: Suspect parameter numbers are assigned to each individual parameter in a parameter group, and to
items that are relevant to diagnostics but are not presently a parameter in a parameter group.
Note 2 to entry: See SAE J1939 definitions for more details.
4 Voltage classes
Table 1 indicates the range of voltages (as defined in ISO 23285).
Table 1 — Voltage classes
Maximum working voltage
Voltage class
V DC V AC RMS
VC-A 0 < U ≤ 60 0 < U ≤ 30
VC-A1 0 < U ≤ 32 0 < U ≤ 21
VC-A2 32 < U ≤ 60 21 < U ≤ 30
VC-B 60 < U ≤ 1 500 30 < U ≤ 1 000
VC-B1 60 < U ≤ 75 30 < U ≤ 50
VC-B2 75 < U ≤ 1 500 50 < U ≤ 1 000
U = nominal voltage
NOTE 1 The definition of RMS values in Table 1 is related to a pure sine wave form or the fundamental frequency of
a modulated signal. The RMS value of a modulated signal may differ from them.
NOTE 2 Unipolar PWM is DC. Bipolar PWM is AC.

5 General system overview
5.1 General
Initially, the basis for the communication between supply system (SS) and consumer systems (CSs), high
power interface (HPI) controllers (shown in Figure 2 and Figure 3) shall use the ISOBUS as specified in the
ISO 11783 series.
NOTE 1 High speed ISOBUS and other alternative communication media such as Automotive Ethernet and
TM 1)
EtherCAT  based technologies can be used but likely need an update to this document. For information, ISO
technical committees TC 82, TC 23 and TC 127 are collaboratively working on high-speed secure communication
interfaces.
NOTE 2 Topologies showed in this clause are only examples, implementations can differ from them (e.g. in number
of interfaces).
If applicable, as basis for the communication between Power Converter/Switch Controller (PC/S-C) and
application (APP)/load (shown in Figure 2), the fieldbus as defined in Clause 7 may be used.
The communication shall follow the TIM approach on ISOBUS.
NOTE 3 Advantage of this approach is using already defined measures like secure communication, usage of an
existing automation state machine, etc. Refer to AEF guidelines 023 on automation and 040 on security for details.
NOTE 4 As diagnostics is not in scope, Annex D gives an informative overview of feasible DTCs.
5.2 Basic AC-system topology
Typically, an electric AC drive system consists of one Power Converter (PC, e.g. a three-phase inverter)
within the SS which is connected to at least one Application (APP), in particular an AC-load (ACL), on the side
of a CS via one HPI. A SS provides at least one HPI.
Application specific communication shall use ISOBUS, e.g. for transmission of working process data from
implement (as CS) to tractor (as SS).
Load specific communication shall use the fieldbus for ACL identification and transmission of feedback.
The fieldbus shall be a 1:1 connection, enabling reliable and unambiguous communication between Power
Converter (PC) and load logical box (LLB).
NOTE The load specific communication between SS and CS is functionally necessary since there is a split in the
electric drive between Power Converter PC and ACL.
TM
1) EtherCAT is a Tradename of Beckhoff, used as an example of a suitable product available commercially. This
information is given for the convenience of users of this document and does not constitute an endorsement by ISO of this
product.
Key
Symbol Description Symbol Description
power connection
signal/bus connection optional signal connection
I supply system II consumer system
1 high-power interface supply system communication bus (e.g. tractor
bus)
2 ISOBUS connector consumer system communication bus (e.g.
implement bus)
3 power lines 7 fieldbus (used also for interlock function)
4 ISOBUS 8 feedback signal (e.g. sensor signal)
ACL AC-load (e.g. electric motor) PC (DC/AC) power converter
APP application PC-C power converter controller
C controller of a device REC rectifier (AC/DC power converter)
C DC link capacitor T transmission
DC
CE combustion engine TC task controller
DCLNK DC link TIM-C tractor implement management - Client
HPI-C HPI - control TIM-S TIM - server
HPI-MC HPI – master control VT virtual terminal
(user interface, e.g. display)
LLB load logical box
Figure 2 — AC-system topology example with two loads
The SS and CSs may include additional communication bus systems (as shown in Figure 2), these are not
within the scope of this document.
The interaction (sequences for identification, initialization, operation and shutdown) between SS [including
2)
the Tractor Implement Management (TIM) server on-board, e.g. a tractor] and CS [including TIM client
and Task Controller (TC) on-board e.g. an implement] is described in Clauses 6, 7 and 9 for fieldbus-based
systems.
2) Depending on specific topologies, an implement can also be a server.

The total number of TCs of a CS is not specified by the example in Figure 2, it is permitted to use a dedicated
TC per APP.
5.3 Basic DC-system topology
Key
Symbol Description Symbol Description
power connection
signal/bus connection optional signal connection
I supply system II consumer system
1 high-power interface (HPI) consumer system communication bus (e.g.
implement bus)
2 ISOBUS connector 7 interlock loop
3 power lines 8 feedback signal (e.g. sensor signal)
4 ISOBUS 9 interlock signal line breaker
supply system communication bus (e.g.
tractor bus)
ACL AC-load (e.g. electric motor) REC rectifier (AC/DC power converter)
APP application S switch (contactor or solid-state switch,
including pre- and discharge unit)
C controller of a device S-C switch controller
CDC DC link capacitor T transmission
CE combustion Engine TC task controller
DCLNK DC link TIM-C tractor implement management–client
HPI-C high-power interface–control TIM-S tractor implement management–server
HPI-MC high-power interface–master control VT virtual terminal
(user interface, e.g. display)
INV inverter (DC/AC power converter)
Figure 3 — DC-system topology example with two loads
Typically, an electric DC drive consists of a switch (this includes a contactor or a solid-state switch and
as well as a pre-/discharge device) that is connected with at least one APP (e.g. a three-phase inverter for

a three-phase electrical machine) on the CS side via one HPI. A SS provides at least one HPI. A CS usually
includes a DC-load (DCL). A CS may act as SS for a subsequent CS.
Application specific communication shall use ISOBUS, e.g. for transmission of working process data from
implement (as CS) to tractor (as SS).
NOTE Load specific communication between SS and CS is not needed since there is no split in the electric drive (as
shown in Figure 3: Split between INV and ACL in APP #1).
SS and CSs may include additional communication bus systems (as shown in Figure 3). These communication
systems are not covered by this document.
The interaction (sequences for identification, initialization, operation and shutdown) between a SS (including
3)
the TIM server on-board e.g. a tractor) and a CS (including TIM client and TC on-board e.g. an implement) is
described in Clauses 6, 8 and 10 for Interlock Loop (IL)-based systems.
The total number of TCs of a CS is not specified by the example in Figure 3, it is permitted to use a dedicated
TC per APP.
6 Communication process and system handshake
6.1 System handshake phases
The system handshake determines the communication between the LLB, PC/S, HPI-MC, and HPI-C (see
Clause 5 for details of the topologies and abbreviations). The system handshake consists of the following
phases (see also Figure 4 and 5) after connecting the ISOBUS interface and the HPI:
a) identification;
b) initialization;
c) operation; and
d) shutdown.
NOTE 1 The “identification phase” is known in other industries (e.g. construction) as “discovery phase”.
NOTE 2 LLB is only used mandatorily in an AC-system per 5.2. In DC-systems, it is an option. Hence, the
corresponding process steps are only needed if an LLB is applied.
The system handshake shall use the existing TIM function state machine. This will be defined in 6.4.
NOTE 3 For details on the TIM function state machine, see AEF 023 RIG3 (2023).
After address claiming on ISOBUS as common, the start-up sequence is split into the above mentioned two
phases (more details see 6.4):
— The identification phase (see Figure 8), where the PC/S shall be assigned to the corresponding HPI-C:
— For fieldbus-based systems, the sequence per Clause 9 shall be used, or
— For IL-based systems, the sequence per Clause 10 shall be used.
— The initialization phase, where the PC/S shall receive:
— Load-specific data from the LLB to initialize the PC/S subordinated controls (e.g. torque control),
and
— Application-specific data from the application ECU (specific HPI-C / TC or specific SS ECU) to initialize
the higher-level controls (e.g. speed control).
3) Depending on specific topologies, an implement can also be a server.

As a fallback if the identification processes per Clauses 9 and 10 are not supported or not successful, each SS
HPI-C and CS HPI-C shall support a manual configuration page as it is defined by TIM for other applications
as hydraulic interfaces.
NOTE 4 The manual configuration will be performed by the operator.
Generally, a system may have both, a fieldbus and an IL connection. If this applies, the fieldbus has a higher
priority since it enables a higher number of functions and is used for operating the system. For details see
ISO 23316-4:2023, 4.8.
NOTE 5 Inherently, a PC/S or an APP can have both, a fieldbus and an IL. It depends on the completed system which
one is active finally.
6.2 Conditions for system handshake
It is a precondition that signals that are sent by the HPI-C to the PC/S and vice versa shall be routed via the
ISOBUS through the HPI-MC and the SS communication bus.
Objects that are sent by the LLB to the PC/S and vice versa shall be always routed directly via the fieldbus
(so this is a mandatory precondition for the clauses on fieldbus-based systems).
The whole ‘electric drive’ (consisting of PC/S and APP) shall be controlled by the HPI-C or in specific cases
the HPI-MC via the TIM function state machine (at least for enabling/disabling, consider the different control
modes per ISO 23316-4 and ISO 23316-5).
NOTE 1 The controlling instance - HPI-C or HPI-MC - will be chosen by the application control type per Table A.2.
It defines two modes: “Implement-controlled” and “tractor-controlled”. In the “implement-controlled” mode -as
common – the CS’s HPI-C requests as a TIM client a function of the TIM server at the SS. Whereas in the “tractor-
controlled” mode – which is not common – the SS’s HPI-MC requests the control of a function at the CS.
NOTE 2 The status of the TIM function state machine is reflected in the VT by the TIM automation states [see
AEF 023 RIG3 (2023) Annex E.1 also].
CAN messages between PC/S-C and HPI-C shall include a command byte which is the (TIM) Function ID as
representation of the PC/S address. This shall differentiate the PC/Ss onboard of a certain SS against each
other.
NOTE 3 A similar approach is made within TIM for, e.g., tractor’s hydraulic valves.
NOTE 4 The command byte can be understood as a multiplexer for this message. Within the message structure for
the AC and DC modes, this and additional multiplexers are used for several purposes. For information on messages
(PGNs), see Annex B.
The definitions of the CAN messages and the corresponding message sets shall be compliant to and
documented in ISO 11783 and SAE J1939. Using transport protocol is an option for these messages.
The connection status of each HPI shall be monitored (see details in 6.3).
For each sent signal, the receiver shall send an acknowledgement as confirmation to the sender.
NOTE 5 Similar requirement exists in AEF 023.
6.3 HPI connection status monitoring
Each dedicated electrical HPI shall be monitored in respect of its dedicated connection status (connection
via connector and cable between SS and CS) frequently, this is mentioned by interlock function. This check
shall be performed while the connection status is “disconnected” also for determining an already inserted
connector.
At least one of these two options of connection status monitoring shall be supported:
— IL-based monitoring, and
— Fieldbus-based monitoring.
In fieldbus-based systems, the interlock function shall be provided by monitoring the fieldbus (for details,
see Clauses 7 and 9).
In IL-based systems, the interlock function shall be provided by monitoring a dedicated physical interlock
loop (for details, see Clauses 8 and 10).
If both, IL and fieldbus are available for monitoring the HPI connection status, a decision shall be made by
the PC/S based on ISO 23316-4:2023, 4.8.3. This decision shall be valid from beginning of the identification
phase.
NOTE 1 The physical interface as specified in ISO 23316-2 includes both, fieldbus and dedicated IL pins.
Consequently, a separate interlock function handling and handshake for each interface shall be applied.
NOTE 2 SS or CS internal interlock loops are not the focus of ISO 23316 series. So, the term interlock is used
otherwise as common in automotive industry.
6.4 Interaction with TIM function state machine
This subclause defines the handshake sequence in general. It points out how the phases mentioned in 6.1 are
interacting with the TIM function state machine.
a) As the TIM function state machine is in the state “(0) automation unavailable”, the transition into the
state “(1) automation not ready” shall require in addition to the already defined conditions the connected
status per HPI.
b) As the TIM function state machine is in the state “(1) automation not ready”, the transition into the
state “(2) automation ready to enable” shall require in addition to the already defined conditions the
identification of the APP (load) connected per HPI using fieldbus (LLB addressing) and IL (determination
per Annex C) functionality. Consequently, a logical check is performed which kind of interlock is
implemented and thus which operational modes are generally available.
c) As the TIM function state machine is in the state “(2) automation ready to enable”, the transition into
the state “(3) automation enabled” shall require all the following in this specific sequence:
— For each connected HPI as result and reflection of the successful APP (load) identification, the
HPI-MC assigns a TIM function ID per HPI and sends this assignment information by a destination
specific message ‘TIM server to TIM client’ to the one specific CS HPI-C,
NOTE 1 Generally, an SS HPI-C can be combined with a PC/S-C and a CS HPI-C with a TC.
NOTE 2 One CS HPI-C can control several HPI. A CS (an implement) can contain several HPI-Cs.
— For each connected HPI, the CS HPI-C assigns control type and application control type (see Table A.2
4)
in Annex A) to the corresponding SS HPI-C by sending a message ‘TIM client to TIM server’, this
includes a logical check of possible and allowed modes by the SS HPI-C,
NOTE 3 As defined in Table A.2, the control type and the application control type are only set once,
they will not change during operation.
— Optionally, the HPI-MC and the other HPI-Cs are communicating the needed parameters (see
Table A.4) on the insulation resistance and monitoring per Clause 11,
— For each connected HPI which is using the fieldbus, the LLB sends the load specific initialization
parameters (see Table A.11) to the PC/S-C, if needed the PC/S-C forwards initialization parameters
to the corresponding SS HPI-C and the CS HPI-C,
4) In most cases, the SS HPI-C will be the HPI-MC. In topologies with implements connected in series, this statement is
not valid.
— For each connected HPI, the PC/S-C sends the needed reference values (see Table A.1) as required
per chosen control type via SS HPI-C to the CS HPI-C,
It is recommended to set a quantity reference to ‘0’ if not needed per chosen control type.
— For each connected HPI, the CS HPI-C sends the required initialization values (limits, thresholds
etc. in Table A.2, Table A.5 - Table A.10, Table A.18 to Table A.20) per chosen control type to the
corresponding SS HPI-C and vice versa this SS HPI-C forwards the needed initialization values per
chosen control type to the corresponding CS HPI-C, if needed the SS HPI-C forwards initialization
parameters to the PC/S-C,
— For each connected HPI, the specific controlling HPI-C of CS (TIM client) and SS (TIM server) provide
the information on finished successful initialization.
d) As the TIM function state machine is in the state “(4) automation pending”, the transition into the state
to “(5) automation active” shall require no additional action as already defined.
e) As the TIM function state machine is in the state “(5) automation active”, for each HPI, the CS HPI-C shall
start sending the target values to the corresponding SS HPI-C for starting operation and vice versa the
SS HPI-C (PC/S-C) shall start sending actual values as feedback to the CS HPI-C.
Changing the control type and the application control type shall require the deactivation of the HPI and a
complete reinitialization process including stepping back the TIM function state machine.
Figure 4 shows the sequence diagram for a fieldbus-based system. This can also be adapted to an IL-based
system while ignoring the fieldbus specific and adding IL-specific tasks (see Figure 5). These figures are not
including the insulation resistance initializing and monitoring related communication.

Figure 4 — Sequence diagram for a fieldbus-based system without insulation monitoring (see
ISO 23316-6DA)
NOTE 4 For details on fieldbus-based systems, see Clauses 7 and 9. For the handshake specifically, see Clause 9. For
detailed sequence diagrams, see Figures 8 to 11. For insulation monitoring, see Clause 11.
Figure 5 — Sequence diagram for an IL-based system without insulation monitoring (see
ISO 23316-6DA)
NOTE 5 For details on IL-based systems, see Clauses 8 and 10. For the handshake specifically, see Clause 10. For
detailed sequence diagrams, see Figures 17 to 20. For insulation monitoring, see Clause 11.
7 Fieldbus
The fieldbus shall use EtherCAT as described in ISO 23316-4:2023, Clause 5 for the high-speed communication
between SS and CS: The PC/S-C acts as the fieldbus maindevice and the LLB acts as a fieldbus subdevice.
NOTE The necessary data definitions (feedback values such as rotor position, rotor speed, winding temperature,
and initialization values) are listed in A.2.2.
8 HPI interlock function
8.1 Functional requirements
The dedicated interlock signal shall only be used for the following functions:
— determination of AC system topology using open-loop control modes per ISO 23316-4 and a DC system
topology per ISO 23316-5, and
— monitoring the HPI connection status by the SS (e.g. fault detection caused by an unintended disconnect)
for the mentioned topologies.
AC systems topology using open-loop control modes may use one of the following options:
— Field-bus based system, or
— IL-based system.
In case of any interruption of the interlock signal, the VC-B2 power shall be turned off by the SS in accordance
with the guidance given by ISO 16230-1:2015, 6.2.

Key
Symbol Description Symbol Description
I supply system II consumer system
III consumer and supply system S switch (contactor or solid-state switch, including
pre- and discharge unit)
C controller of a device S-C switch controller
HPI-C high-power interface - control TC task controller
HPI-MC high-power interface – master control TIM-C tractor implement management - client
IC input circuit TIM-S tractor implement management - server
INV inverter (DC/AC power converter) VT virtual terminal
(user interface, e.g. display)
Figure 6 — Simplified topology example for a SS with multiple CSs and multiple HPIs
If IL interruption is monitored before pre-charge is started, the pre-charge shall not be performed.
NOTE 2 Electric units on the SS and CS are part of their own machine interlock loops if applied; they do not include
or interfere with the HPI interlock loop.
In cases of multiple implements, the interlock handling and hardware handshake shall be performed
between each HPI (first implement with second implement, second implement with third implement, and so
on). See topology example in Figure 6.
8.2 Functional principle
Figure 7 shows the functional principle. The illustrated IL-switch on the SS side has following functions:
— When the internal check on the CS side is faultless, the IL-switch shall be closed.
— If more than one HPI is used on the tractor-implement-combination and more than one CS is connected,
each SS shall identify the CS, which is connected to the relevant physical HPI via demanding the toggling
of IL-switch (identification procedure is described in Clause 10).
— In series to the IL-switch a resistance R = 1 kΩ ±10 % shall be connected.
IL
...