BRITISH STANDARD BS AU 243 3 1991 ISO 7637 2 1990 Methods of test for Electrical disturbance by conduction and coupling — Part 3 Electrical transient conduction along supply lines only on commercial v[.]
BRITISH STANDARD BS AU 243-3:1 991 ISO 7637-2: 990 Methods of test for Electrical disturbance by conduction and coupling — Part 3: Electrical transient conduction along supply lines only on commercial vehicles with 24 V supply BS AU 243-3:1 991 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Automobile Standards Policy Committee (AUE/- ) to Technical Committee AUE/1 6, upon which the following bodies were represented: Association of Trailer Manufacturers British Cable Makers Confederation Department of Transport Institution of Electrical Engineers Motor Industry Research Association National Caravan Council Ltd Society of Motor Manufacturers and Traders Ltd This British Standard, having been prepared under the direction of the Automobile Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 29 November 991 © BSI 04- 999 The following BSI references relate to the work on this standard: Committee reference AUE/1 Draft for comment 88/73081 DC ISBN 80 201 Amendments issued since publication Amd No Date Comments BS AU 243-3:1 991 Contents Page Committees responsible Inside front cover National foreword ii Scope Normative reference Test procedures Test instrument description and specifications General techniques to improve electromagnetic compatibility of device Annex A (normative) Failure mode severity classification Figure — Conducted voltage transients measurement test setup Figure — Conducted current transients measurement test setup Figure — Transient immunity test setup Figure — Schematic diagram of artificial network Figure — | Z PB | as a function of frequency from 00 kHz to 00 MHz (AB short- circuited) Figure — Test pulse a and b Figure — Test pulse Figure — Test pulse 3a Figure — Test pulse 3b Figure — Test pulse Figure 1 — Test pulse Table A — Test levels 11 Table A — Example 11 Table A — Example Publication(s) referred to © BSI 04- 999 10 12 Inside back cover i BS AU 243-3:1 991 National foreword This British Standard has been prepared under the direction of the Automobile Standards Policy Committee and is identical with ISO 7637- “Road vehicles — Electrical disturbance by conduction and coupling — Part 2: Commercial vehicles with nominal 24 V supply voltage — Electrical transient conduction along supply lines only”, published by the International Organization for Standardization (ISO) The Technical Committee has reviewed the provisions of ISO 6722- 3, to which reference is made in the text and has decided that they are acceptable for use in conj unction with this standard A British Standard does not purport to include all the necessary provisions of a contract Users of British Standards are responsible for their correct application Compliance with a British Standard does not of itself confer immunity from legal obligations Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages to 2, an inside back cover and a back cover This standard has been updated (see copyright date) and may have had amendments incorporated This will be indicated in the amendment table on the inside front cover ii © BSI 04- 999 ISO 7637-2:1 990 (E) Scope In special cases, it may be necessary to apply This part of ISO 7637 specifies test methods and procedures to ensure the compatibility to conducted electrical transients of equipment installed on commercial vehicles fitted with a 24 V electrical system It describes bench tests for both the inj ection and measurement of transients Functional status classifications for immunity to transients are given in Annex A NOTE General guidelines for the evaluation of transient emissions, test procedures for which are given in clause , will form the subj ect of a future addendum Normative reference The following standard contains provisions which, through reference in this text, constitute provisions of this part of ISO 7637 At the time of publication, the edition indicated was valid All standards are additional test pulses However, some test pulses may be omitted, if a device — depending on its function or its connection — is not influenced by comparable transients in the vehicle It is part of the vehicle manufacturer’s responsibility to define the test pulses required for a specific device To ensure proper vehicle operation in the electromagnetic environment, on- board testing is essential 3.2 Test temperature and test voltage The ambient temperature during the test shall be 23 °C ± °C The test voltages shall be as follows: ±1V UB = 24 V ± 0, V UA = 27 V unless other values are agreed upon by the users of subj ect to revision, and parties to agreements based this part of ISO 7637, in which case such values on this part of ISO 7637 are encouraged to shall be documented in the test reports investigate the possibility of applying the most recent edition of the standard indicated below Members of IEC and ISO maintain registers of 3.3 Transient emissions test 3.3.1 Voltage transients currently valid International Standards Voltage transients from the disturbance source, the ISO 6722- 3: 984, Road vehicles — Unscreened device under test, are measured using the artificial low-tension cables — Part 3: Conductor sizes and network to standardize the impedance loading on dimensions the device under test (see 4.1 ) The disturbance source is connected via the artificial network to the Test procedures 3.1 General Methods for measuring the transient emission on supply lines and test methods for the immunity of devices against such transients are given These tests, called “bench tests”, are made in the laboratory 1) The bench test methods, some of which require the use of the artificial network, will provide comparative results between laboratories They also give a basis for the development of devices and systems and may be used during the production phase A bench test method for the evaluation of the immunity of a device against supply line transients may be performed by means of a test pulse generator; this may not cover all types of transients which can occur in a vehicle Therefore, the test pulses described in 4.6 are characteristic of typical pulses shunt resistor R s1 (see 4.2 ) , the switch S (see 4.3 ) and the power supply (see 4.4 ), as given in Figure The leads between the terminals of the disturbance source, the device under test, and the artificial network shall be laid out in a straight parallel line and shall have a length of 0, m ± 0, 05 m The cable sizes shall be chosen in accordance with ISO 6722- The disturbance voltage is measured at the terminals P and B of the artificial network (see Figure ) using a voltage probe and an oscilloscope or waveform acquisition equipment Repetitive transients are measured with switch S closed If the transient is caused by a supply disconnection, measurement is started at the moment of opening switch S 3.3.2 Current transients The test setup for measuring the disturbance current is shown in Figure The disturbance source is connected via the artificial network to the power supply Resistor Rs2 (see 4.2 ) is connected to the terminals of the artificial network on the power supply side (see Figure 2) 1) A future part of ISO 7637 will cover on- board vehicle tests © BSI 04- 999 ISO 7637-2:1 990 (E) Figure — Conducted voltage transients measurement test setup Figure — Conducted current transients measurement test setup The leads between the terminals of the disturbance source and the artificial network shall be laid out in a straight parallel line and shall have a length of 0, m ± 0, 05 m The disturbance source is disconnected by the switch S The disturbance current measurement is started when switch S is opened The disturbance current should be measured between the artificial network and the device under test as close to the artificial network as possible 3.4 Transient immunity test The test setup for transient immunity measurements of electrical/electronic devices is given in Figure Figure — Transient immunity test setup The leads between the terminals of the test pulse generator and the device under test shall be laid out in a straight parallel line and shall have a length of 0, m ± 0, 05 m The test pulse generator (see 4.6 ) is set up to provide the specific pulse polarity, amplitude, duration and resistance with switch T (see 4.3 ) open (The appropriate values are selected from Annex A ) Next, the device under test is connected to the generator by closing switch T Depending on the real conditions, the function of the device under test should be evaluated during and/or after the application of the test pulses © BSI 04- 999 ISO 7637-2:1 990 (E) For correct generation of the required test pulses, it 4.2 Shunt resistors Rs1 and Rs2 may be necessary to switch the power supply on and The shunt resistor Rs1 (see Figure 1) simulates the off The switching can be performed by the test pulse dc resistance of other vehicle devices which are generator if the power supply is integral to it connected in parallel to the device under test and are not disconnected from it by the ignition switch Test instrument description and Rs1 is selected to correspond to the resistance specifications measured on the wiring harness between the disconnected ignition switch terminal and ground, 4.1 Artificial network with the switch off, and shall be specified by the The artificial network is used as a reference vehicle manufacturer In the absence of any standard in the laboratory in place of the impedance specification, value of Rs1 = 40 shall be used If of the vehicle wiring harness in order to determine a wire-wound aresistor is used, the winding shall be the behaviour of equipment and electrical and bifilar (i.e with a minimum reactive component) electronic devices A schematic diagram is given in Shunt resistor Rs2 (see Figure 2) is used during Figure transient measurements In the absence of The artificial network should be able to withstand a current any specification, value of Rs2 = shall be used continuous load corresponding to the requirements The shunt resistorashall have an adequate power of the device under test dissipation rating The resulting values of impedance | ZPB| , measured 4.3 Switch S and switch T between the terminals P and B while terminals A and B are connected together, are given in Figure The switch S (see Figure and Figure 2) as a function of frequency assuming ideal electric significantly influences the disturbance transients when tests are performed in accordance with 3.2 components In reality, the impedance of an artificial network should not deviate more NOTE A specification for a switch S with reproducible properties is in preparation In the interim it is proposed to use a than 10 % from the curve given in Figure standard production switch that is used with the device under The main characteristics of the components are as test and to perform a sufficient number of tests to ensure a statistically valid sample follows: — maximum continuous load current, I = 70 A The switch T (see Figure 3) is a disconnecting switch which does not influence the disturbance transients — inductance, L = 4H (air-core winding) The current rating of switch T should be sufficient to — internal resistance between terminals P and A: handle the required loads RL < 5m7 4.4 Power supply — capacitor, C2 = 0,1 4F for working voltages When a battery is used, a charging source is needed of 200 Vac and 500 Vdc to achieve the specified reference levels If a standard power supply (with sufficient current capacity) is used in bench testing to simulate the battery, it is important that the low internal impedance of the battery also be simulated The continuous supply source shall have an internal resistance Ri less than 0,01 dc and an internal impedance Zi = Ri for frequencies less than 400 Hz The output voltage shall not deviate more than V from to maximum load (including in-rush current) and shall recover 63 % of its maximum excursion within 100 4s The superimposed ripple voltage, Ur, shall not exceed 0,2 V peak-to-peak and have a maximum frequency of 400 Hz Figure — Schematic diagram of artificial network © BSI 04-1999 ISO 7637-2:1 990 (E) Figure — | ZPB| as a function of frequency from 00 kHz to 00 MHz (AB short-circuited) 4.5 Measurement instrumentation 4.5.4 Waveform acquisition equipment Equipment that is capable of acquiring fast rise time transient waveforms may be used instead of an This should preferably be a storage oscilloscope with oscilloscope the following specifications: 4.6 Test pulse generator — band width: at least 100 MHz The test pulse generator shall be capable of — writing speed: at least 100 cm/4s producing the test pulses described in 4.6.1 to 4.6.7 — input sensitivity: at least mV/division and shall be adjustable within the limits given in The recording may be made with an oscilloscope Figure to Figure 13 camera or any other appropriate recording device Tolerances for the parameters are 4.5.2 Voltage probe: ± 10 % for time and resistance, and — attenuation: 100/1 + 10 % for voltage (Va and Vs) — maximum input voltage: at least kV Recommended values for the evaluation of — input impedance, Z, as a function of the immunity of devices can be chosen from Table A.1 frequency, R: 4.6.1 Test pulse 1a and 1b R Z This test pulse is a simulation of transients due to MHz > 40 k7 supply disconnection from inductive loads; it applies to a device under test if, as used in the vehicle, it 10 MHz > k7 remains connected directly in parallel with an 100 MHz > 0,4 k7 inductive load The pulse shape and parameters are given in — maximum length of the probe cable: m Figure — maximum length of the probe ground: 0,13 m 4.5.1 Oscilloscope NOTE The lengths will influence the measurement results and should be stated in the test report 4.5.3 Current measuring probe: — minimum measuring range: 20 A — maximum working voltage: 500 V — bandwidth (– dB): at least to 15 MHz (Hall effect probe) — attenuator accuracy: better than % © BSI 04-1999 ISO 7637-2:1 990 (E) NO TE The time neces s ary b etween the dis connection of the s up p ly s ource and the ap p lication of the tes t p uls e, t3 , s hall b e minimiz ed Figure — Test pulse a and b 4.6.2 Test pulse 4.6.3 Test pulses 3a and 3b This tes t p uls e is a s imulation of trans ients due to Thes e tes t p uls es are a s imulation of trans ients , the s udden interrup tion of current in an inductor which occur as a res ult of the s witching p roces ses connected in series with a device under tes t The characteris tics of these trans ients are It s imulates trans ients which may for examp le occur due to the following: after the ignition is influenced b y dis trib uted cap acitance and inductance of the wiring harness s witched off, dc motors , which are connected to the The p uls e s hap es and p arameters for tes t p uls es a s ame s witch as the ignition, may continue rotating and b are given in Figure and Figure due to their inertia, thus acting as generators Their res p ectively inductance creates a transient on switching off the s up p ly line The p uls e shap e and p arameters are given in Figure © BS I 4- 99 ISO 7637-2:1 990 (E) Figure — Test pulse Figure — Test pulse 3a © BSI 04- 999 ISO 7637-2:1 990 (E) Figure — Test pulse 3b 4.6.4 Test pulse This pulse simulates supply voltage reduction caused by energizing the starter- motor circuits of internal combustion engines (excluding spikes associated with starting) The pulse shape and parameters are given in Figure © BSI 04- 999 ISO 7637-2:1 990 (E) Figure 1 — Test pulse The following general considerations of the dynamic behaviour of alternators during load dump apply: a) The internal resistance of an alternator, in the case of load dump, is mainly a function of alternator rotational speed and excitation current b) The internal resistance, Ri, of the load dump test pulse generator shall be obtained from the following relationship: Figure — Test pulse 4.6.5 Test pulse Rj 10 = 0, × Vnom × Nact × Irated × 000 –1 where This test pulse is a simulation of load dump Vnom is the specified voltage of the alternator; transient occurring in the event of a discharged Irated is the specified current at an alternator battery being disconnected while the alternator is generating charging current at the moment of the speed of 000 –1 battery being disconnected with other loads Nact remaining on the alternator circuit at this moment; reciprocal minutes the load dump amplitude depends on the alternator speed and on the level of the alternator field excitation at the moment of the battery being disconnected The load dump pulse duration depends essentially on the time constant of the field excitation circuit and on the pulse amplitude (as given in ISO 8854); is the actual alternator speed, in Vs , Ri, and the pulse duration td; in all cases small values of Vs are correlated with small values of Ri and t d, and high values of Vs with high values of Ri and td c) The pulse is determined by the peak voltage the internal resistance Load dump may occur on account of a battery being disconnected resulting from cable corrosion, poor connection or the battery being disconnected intentionally while the engine is running The pulse shape and parameters are given in Figure 1 © BSI 04- 999 ISO 7637-2:1 990 (E) General techniques to improve electromagnetic compatibility of device 5.1 Limiting emissions from disturbance sources The most effective way to suppress emissions is at the source D isturbance transients should be suppressed internal to, or at the terminals of, the disturb ance source by means of diodes, Zener diodes, varistors, 5.2 Equipment immunity improvement The immunity of devices can be improved b y using diodes, Zener diodes, varistors, capacitors, suppression filters, damping resistors, etc , which should be connected to terminals likely to receive disturbance transients Furthermore, the choice of mounting location can aid in providing immunity 5.3 Additional suppression techniques Practical means of transient suppression may be obtained b y one or more of the following methods: damping resistors, capacitors, suppression filters, a) provision of a “clean” independent power etc supply for susceptible equipment; If it is not possible to suppress transients internally b ) insertion of dumped suppression components or at the terminals, the suppression unit shall be at strategic points in the wiring harness; placed as close to the source as possible c) use of harness with low pass filter properties; The use of a Zener diode, varistor and other d) careful routing of harnesses components at the main network terminals may give sufficient protection for susceptib le equipment if no disconnecting switch is located between the transient source and the suppressor © BSI 04- 999 ISO 7637-2:1 990 (E) Annex A (normative) Failure mode severity classification A.1 Scope The purpose of this annex is to provide a method of A.4 Classification of functional status All classifications given below are for the total device/system functional status NOTE The word “function” as used here only concerns the function performed by the electronic system classifying the functional status of automotive electronic devices upon application of the test conditions described in this part of ISO 7637 Class A The process described in this annex applies only to the bench testing of automotive electronic devices using the methods described in this part of All functions of a device/system perform as designed during and after exposure to disturbance Class B All functions of a device/system perform as designed during exposure: however, ISO 7637 one or more of them can go beyond A.2 General specified tolerance All functions return It must be emphasized that components or systems automatically to within normal limits shall only be tested with those conditions which after exposure is removed Memory represent the environments to which the device functions shall remain Class A would actually be subj ected, i e as used in a vehicle This will help ensure sound technical and Class C economically optimized designs for susceptible returns automatically to normal systems It should also be noted that this annex is not meant to be a product specification and cannot function as A function of a device/system does not perform as designed during exposure but operation after exposure is removed Class D A function of a device/system does not one Nevertheless, using the concepts described in perform as designed during exposure this document and by careful application and and does not return to normal operation agreement between manufacturer and user, it until exposure is removed and the device would be possible to develop a document giving the system is reset by simple “operator/use” functional status requirements for a specific device action This could then, in fact, be a statement of how a Class E One or more function of a device/system particular device could be expected to perform under does not perform as designed during and the influence of the specified disturbance transients after exposure and cannot be returned to (see A.7 ) proper operation without repairing or A.3 Essential elements of failure mode replacing the device/system classification system There are three elements required to describe a general failure mode severity classification They are Functional status classification: Operational status of a device during and after exposure to an electromagnetic environment Test pulse and method: Reference to the representative test pulse applied to the device under test and test method (In this case this information is contained in the body of this part of ISO 7637 Test pulse severity: Specification of the severity level of essential pulse parameters A.5 Classification of test pulse severity The suggested minimum and maximum severity levels are given in columns I and IV in Table A A selected level for testing at or inbetween these values may be chosen according to the agreement between car manufacturer and supplier In cases where no specific values are defined, it is recommended that levels selected from columns I to IV in Table A be used A.6 Allocation of functional status to test pulse severity Manufacturer and user shall specify the classification of functional status (A.4 ) and of test pulse severity (A.5 ) bearing the specific application of the device in mind Test pulses which not reach the specific device under real conditions, i e when the device is operated in a vehicle, may be omitted A functional impairment of Class C may be acceptable for devices which need not work during the occurrence of distinct pulses (e g flashers during cranking) 10 © BSI 04- 999 ISO 7637-2:1 990 (E) A.7.1 A functional impairment of Class D may b e acceptable for devices the malfunction of which does not cause customer annoyance or inconvenience Example This is an example of how a device supplier might characterize the performance of his device for sales or engineering purposes Tab le A shows the A functional impairment of C lass E is defined primarily for test report purposes and would not characteristics of the device for all applicab le test normally b e acceptable for a device unless under pulses and the functional status after exposure to all special circumstances test severity classification A.7 Presentation of results NO TE The examples in A.7.1 A.7.2 and In testing the device to increasing test pulse severity, care would have to be taken to avoid possible cumulative effects are given to from previous test applications if the same device were used for illustrate how the failure mode severity all tests classification can be used to characterize a device A.7.2 when applying this part of ISO 7637 Example This is an example of how a customer might characterize the minimum requirements for a particular device Table A constitutes a possible product specification to b e used for engineering and purchasing requirements Table A.1 — Test levels Test levels Selected Test pulse a test level c Minimum number V I b II III IV Pulse cycle time of pulses or test time max max 1a 50 – 00 – 50 – 00 000 pulses 0, s s 1b – 275 – 550 – 82 – 1 00 00 pulses 0, s s + 25 + 50 + 75 + 00 000 pulses 0, s s 3a – 35 – 70 – 40 – 00 h 00 ms 3b + 35 + 70 + 40 + 00 h 00 ms 00 ms d d a Test pulses as in b c e – – 10 – 14 – 16 pulse d + 70 + 113 + 56 + 00 pulse d 00 ms 4.6 Values agreed to b etween car manufacturer and supplier The amplitudes are the values of d V s as defined for each test pulse in 4.6 Since the minimum number of test pulses is , no pulse cycle time is given When several pulses are to be ap plied, a minimum delay of b etween pulses shall b e allowed e See 4.6.5 c) The test levels reflect the situation of load dump at generator rated speed Table A.2 — Example Functional status (see A.4) according to test levels Test pulse I II Remarks III IV 1a Not applicable D evice connected with b attery positive 1b Not applicable D evice connected with b attery positive D evice connected with b attery positive Not applicable 3a A A B C 3b A A B C B B C D D evice need not b e operative during etc cranking etc © BSI 04- 999 11 ISO 7637-2:1 990 (E) Table A.3 — Example Test pulse 1a 1b 3a 3b 12 Test level V – 150 – 100 + 50 – 35 + 35 Functional status in Minimum number of accordance with A.4 pulses or test time A B A C C 000 pulses 100 pulses 000 pulses 1h 3h Remarks Not applicable Not applicable © BSI 04-1999 BS AU 243-3:1 991 Publication(s) referred to See national foreword © BSI 04- 999 | | | | | | | | | BSI Ð British Standards Institution | | | | | | | BSI is the independent national body responsible for preparing British Standards It | | | | | | | presents the UK view on standards in E urope and at the international level It is incorporated by Royal Charter Revisions | | | | British Standards are updated by amendment or revision Users of British Standards should make sure that they possess the latest amendments or editions | | | It is the constant aim of BSI to improve the quality of our products and services We | | | | | | | | would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover Tel: 02 8996 9000 Fax: 02 8996 7400 | | BSI offers members an individual updating service called PLUS which ensures that | | | | | | | | | | subscribers automatically receive the latest editions of standards Buying standards Orders for all BSI, international and foreign standards publications should be addressed to Customer Services Tel: 02 8996 9001 Fax: 02 8996 7001 | | | | In response to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been published as British Standards, unless | | | | | | otherwise requested Information on standards | | | | | | | | | BSI provides a wide range of information on national, E urop ean and international standards through its Library and its Technical Help to E xporters Service Various BSI electronic information services are also available which give details on all its products and services Contact the Information C entre Tel: 02 8996 71 1 Fax: 02 8996 7048 | | | Subscribing members of BSI are kept up to date with standards developments and | | | | | | | | | receive substantial discounts on the purchase price of standards For details of these and other benefits contact Membership Administration Tel: 020 8996 7002 Fax: 02 8996 7001 Copyright | | Copyright subsists in all BSI publications BSI also holds the copyright, in the UK, of | | the publications of the international standardization bodies E xcept as permitted | | | | | | under the C opyright, D esigns and Patents Act 988 no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means ± electronic, photocop ying, recording or otherwise ± without p rior written permission from BSI | | | | This does not preclude the free use, in the course of implementing the standard, of necessary details such as symbols, and size, type or grade designations If these | | details are to be used for any other purpose than implementation then the prior | | written permission of BSI must be obtained | | | | | | | | | | | | | | | BSI | | 389 C hiswick High Road | | London | | W4 4AL | | | | | | | If permission is granted, the terms may include royalty payments or a licensing agreement Details and advice can be obtained from the Copyright Manager Tel: 02 8996 7070