BRITISH STANDARD BS ISO

11451-4:2006
Licensed Copy: London South Bank University, London South Bank University, Mon Oct 16 17:36:28 BST 2006, Uncontrolled Copy, (c) BSI

Road vehicles —
Vehicle test methods
for electrical
disturbances from
narrowband radiated
electromagnetic
energy —
Part 4: Bulk current injection (BCI)

ICS 33.100.20; 43.040.10

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 BS ISO 11451-4:2006
Licensed Copy: London South Bank University, London South Bank University, Mon Oct 16 17:36:28 BST 2006, Uncontrolled Copy, (c) BSI

National foreword

This British Standard reproduces verbatim ISO 11451-4:2006 and implements

it as the UK national standard.
The UK participation in its preparation was entrusted to Technical Committee
AUE/16, Electrical and electronic equipment, which has the responsibility to:

— aid enquirers to understand the text;

— present to the responsible international/European committee any

enquiries on the interpretation, or proposals for change, and keep
UK interests informed;
— monitor related international and European developments and
promulgate them in the UK.

A list of organizations represented on this committee can be obtained on

request to its secretary.
Cross-references
The British Standards which implement international publications referred to
in this document may be found in the BSI Catalogue under the section entitled
“International Standards Correspondence Index”, or by using the “Search”
facility of the BSI Electronic Catalogue or of British Standards Online.
This publication does not purport to include all the necessary provisions of a
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Summary of pages
This document comprises a front cover, an inside front cover, the ISO title page,
pages ii and iii, a blank page, pages 1 to 8, an inside back cover and a back
cover.
The BSI copyright notice displayed in this document indicates when the
document was last issued.

Amendments issued since publication

This British Standard was
published under the authority Amd. No. Date Comments
of the Standards Policy and
Strategy Committee
on 31 July 2006

© BSI 2006

ISBN 0 580 48901 9

 BS ISO 11451-4:2006
Licensed Copy: London South Bank University, London South Bank University, Mon Oct 16 17:36:28 BST 2006, Uncontrolled Copy, (c) BSI

INTERNATIONAL ISO
STANDARD 11451-4

Second edition
2006-06-15

Road vehicles — Vehicle test methods for

electrical disturbances from narrowband
radiated electromagnetic energy —
Part 4:
Bulk current injection (BCI)
Véhicules routiers — Méthodes d'essai d'un véhicule soumis à des
perturbations électriques par rayonnement d'énergie électromagnétique
en bande étroite —
Partie 4: Méthode d'injection de courant (BCI)

Reference number
ISO 11451-4:2006(E)
 Licensed Copy: London South Bank University, London South Bank University, Mon Oct 16 17:36:28 BST 2006, Uncontrolled Copy, (c) BSI

ii
 BS ISO 11451-4:2006
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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 11451-4 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 3,
Electrical and electronic equipment.

This second edition cancels and replaces the first edition (ISO 11451-4:1995), which has been technically
revised.

ISO 11451 consists of the following parts, under the general title Road vehicles — Vehicle test methods for
electrical disturbances from narrowband radiated electromagnetic energy:

⎯ Part 1: General principles and terminology

⎯ Part 2: Off-vehicle radiation sources

⎯ Part 3: On-board transmitter simulation

⎯ Part 4: Bulk current injection (BCI)

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blank
 BS ISO 11451-4:2006
Licensed Copy: London South Bank University, London South Bank University, Mon Oct 16 17:36:28 BST 2006, Uncontrolled Copy, (c) BSI

Road vehicles — Vehicle test methods for electrical

disturbances from narrowband radiated electromagnetic
energy —

Part 4:
Bulk current injection (BCI)

1 Scope
This part of ISO 11451 specifies bulk current injection (BCI) test methods for testing the electromagnetic
immunity of electronic components for passenger cars and commercial vehicles regardless of the propulsion
system (e.g. spark-ignition engine, diesel engine, electric motor). The electromagnetic disturbance considered
in this part of ISO 11451 is limited to continuous narrowband electromagnetic fields.

Part 1 of ISO 11451 gives definitions, practical use and basic principles of the test methods.

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 11451-1:2005, Road vehicles — Vehicle test methods for electrical disturbances from narrowband
radiated electromagnetic energy — Part 1: General principles and terminology

3 Test conditions
The applicable frequency range for this test method is 1 MHz to 400 MHz. The frequency range of the BCI test
method is a direct function of the current probe characteristics. More than one type of current probe may be
required to cover the Applicable frequency range.

The users shall specify the test severity level(s) over the frequency range. Suggested test severity levels are
given in Annex C. These test severity levels are expressed in terms of the equivalent root-mean-square value
of the unmodulated wave.

Standard test conditions are given in ISO 11451-1 for the following:

⎯ test temperature,

⎯ supply voltage,

⎯ modulation,

⎯ dwell time,

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⎯ frequency step sizes,

⎯ definition of test severity levels, and

⎯ test signal quality.

4 Test instrument description and specification

4.1 BCI system

BCI is a method of carrying out immunity tests by inducing disturbance signals directly into the wiring harness
by means of a current injection probe. The injection probe is a current transformer through which the wires of
the device under test (DUT) are passed. Immunity tests are then carried out by varying the test severity level
and frequency of the induced disturbance.

BCI shall be conducted on each individual system fitted to the vehicle.

4.2 Instrumentation

Figure 1 shows an example of a BCI test configuration.

An injection probe or set of probes capable of operating over the test frequency range is required to interface
the test equipment of the DUT. The probe shall be capable of withstanding a continuous input power over the
test frequency range regardless of the system loading.

The current measurement probe or set of probes shall be capable of operating over the test frequency range.
The current measurement probe(s) shall be terminated in the load impedance at which they are calibrated.

4.3 Test set-up

The vehicle should be tested as built; no additional grounding connections are allowed. Tests should be
performed inside a shielded room.

The distance between the vehicle and all other conductive structures, such as the walls of a shielded room
(with the exception of the ground plane underneath the vehicle) shall be a minimum of 0,5 m.

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Licensed Copy: London South Bank University, London South Bank University, Mon Oct 16 17:36:28 BST 2006, Uncontrolled Copy, (c) BSI

5 Test procedure

5.1 Test plan

Prior to performing the tests, a test plan shall be prepared; it shall include interface test points, mode of
operation for the DUT, acceptance criteria for the DUT, and any special instructions and changes from the
standard test. Each DUT shall be verified under the most significant conditions, i.e. at least in stand-by mode
and in a mode where all the actuators can be excited.

5.2 Test methods

CAUTION — Hazardous voltages and fields may exist within the test area. Care shall be taken to
ensure that the requirements for limiting the exposure of humans to RF energy are met.

There are two test methods for the BCI test: the Substitution method and the Closed-loop method (see 5.2.1
and 5.2.2 respectively).

For both tests, the test equipment shall be connected in a manner similar to that shown in Figure 1.

Dimensions in millimetres

Key
1 signal generators
2 broadband amplifier
3 RF 50 Ω directional coupler
4 RF power level measuring device or equivalent
5 RF injection probe
6 RF current measurement probe (required for Closed-loop method, optional for Substitution method)
7 DUT
8 spectrum analyser or equivalent (required for Closed-loop method, optional for Substitution method)

NOTE It is recommended that appropriate ferrite chokes be placed on the coaxial cables to the injection and current
measurement probes.

Figure 1 — Example of BCI test configuration

5.2.1 Substitution method

This method is based upon the use of forward power as the reference parameter for calibration and test.

In this method, the specific test level (current, voltage or power) shall be calibrated prior to the actual testing.

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The test with the DUT is then conducted by subjecting it to the test signals based on the calibrated values as
predetermined in the test plan.

Measurements using this method can be affected by coupling between the injection probe and the wiring
harness as well as by reflected energy.

Mount the current injection probe around the harness (150 ± 10) mm from the connector or the outlet aperture
of the DUT being tested on the vehicle.

Where the harness contains a number of branches to a DUT, the test should be repeated with the current
probe(s) clamped around each of the branches (150 ± 10) mm from the branch termination. Under these test
conditions, the measuring probe, if used, shall be left at its previous distance from the DUT.

Using the pre-calibrated level of forward power (see Annex A), conduct a search for events over the frequency
range of the injection probe.

For each event, record the lowest forward power to the probe as the threshold of immunity even if this is found
with the injection probe in different positions at different frequencies.

A current measurement probe may optionally be mounted between the current injection probe and the DUT. It
may provide extra useful information but it may also modify the test conditions. Where this probe is used, the
measured current cannot be used to determine the performance of the DUT, but should be retained and used
during investigative work for the causes of events and the variances in test conditions after system
modifications.

5.2.2 Closed-loop method

The RF to the current injection probe shall be increased until:

⎯ the predetermined maximum test current level, measured using the current measurement probe, is
reached, or

⎯ the maximum forward power (defined in the test plan) to the injection probe is achieved.

The current measurement probe shall be calibrated using the method in Annex B.

Record the threshold of susceptibility as a function of frequency.

5.3 Test report

When required in the test plan, a test report shall be submitted detailing information regarding the test
equipment, test site, systems tested, frequencies, power levels, system interactions and any other relevant
information regarding the test.

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Licensed Copy: London South Bank University, London South Bank University, Mon Oct 16 17:36:28 BST 2006, Uncontrolled Copy, (c) BSI

Annex A
(normative)

Current injection probe calibration method

To determine the injected current flowing, the forward power measurement across a calibration fixture is used.
Figure A.1 shows an example of a test equipment configuration for the current injection probe calibration.

Mount the current injection probe centred in the calibration fixture (see Figure A.2), and while sweeping the
test frequency range, monitor the forward power required to achieve the current at which testing is to be
conducted.

As an alternative method, once testing of the system is complete and all data has been recorded, mount the
current injection probe in the calibration fixture. At each frequency showing an event, the recorded forward
power levels are applied to the probe. The currents then observed in the calibration fixture are those at which
events within the system occurred.

Key
1 shielded enclosure
2 50 Ω coaxial load, VSWR 1,2:1 max
3 calibration fixture
4 injection probe
5 50 Ω attenuator
6 spectrum analyser or equivalent
7 RF power level measuring device (two are required)
8 RF 50 Ω dual directional coupler (with 30 dB minimum decoupling coefficient)
9 broadband amplifier with 50 Ω output impedance
10 RF signal generator

Figure A.1 — Example of current injection probe calibration configuration

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 BS ISO 11451-4:2006
Licensed Copy: London South Bank University, London South Bank University, Mon Oct 16 17:36:28 BST 2006, Uncontrolled Copy, (c) BSI

Key
1 insulation
2 removable metal cover
3 current injection probe
4 direct connection to 50 Ω measurement equipment
5 direct connection to 50 Ω load

Figure A.2 — Example of calibration fixture (jig)

The physical size of the calibration fixture shall be in accordance with the probe manufacturer’s requirements.

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 BS ISO 11451-4:2006
Licensed Copy: London South Bank University, London South Bank University, Mon Oct 16 17:36:28 BST 2006, Uncontrolled Copy, (c) BSI

Annex B
(normative)

Current measurement probe calibration method

Mount the current measurement probe in the proper size calibration fixture with the probe concentric about the
centre conductor of the fixture (see Figure B.1).

Record the output of the current measurement probe as a function of frequency while maintaining a constant
RF calibration signal power.

Based on a known termination impedance, the output voltage versus input current can be determined.

Key
1 RF signal generator
2 broadband amplifier with 50 Ω output impedance
3 directional coupler with power meters
4 calibration fixture
5 current measurement probe being calibrated
6 RF termination 50 Ω
7 spectrum analyser or equivalent

Figure B.1 — Example of current measurement probe calibration configuration

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 BS ISO 11451-4:2006
Licensed Copy: London South Bank University, London South Bank University, Mon Oct 16 17:36:28 BST 2006, Uncontrolled Copy, (c) BSI

Annex C
(informative)

Function performance status classification (FPSC)

NOTE A detailed of the application of function performance status classification is given in ISO 11451-1:2001,
Annex A.

Table C.1 — Suggested test severity levels

Value
Test severity level
mA
I 25
II 50
III 75
IV 100
V Specific value agreed between the users
of this part of ISO 11451 if necessary

Table C.2 — Frequency bands

Frequency range
Frequency band
MHz
F1 W 1 to u 10
F2 > 10 to u 30
F3 > 30 to u 80
F4 > 80 to u 200
F5 > 200 to u 400

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 BS ISO
11451-4:2006
BSI — British Standards Institution
Licensed Copy: London South Bank University, London South Bank University, Mon Oct 16 17:36:28 BST 2006, Uncontrolled Copy, (c) BSI

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