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ISO16750-3-2012

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ISO16750-3-2012Road vehicles — Environmentalconditions and testing for electricaland electronic equipment —Part 3:Mechanical loadsContents PageForeword.............................................................................................................................................Iso16750-3:2012[EContentsPageForewordScope12Normative references1Terms and definitions4Tests and requirements4.1ibration4.2 Mechanical shock274.3 Free fall…294.4 Surface strength/ scratch and abrasion resistance294.5 Gravel bombardmentCode letters for mechanical loads29Documentation…,…………111111130Annex A (informative) Guideline for the development of test profiles for vibration tests.32Annex B (informative) Recommended mechanical requirements for equipment depending on themounting location44Bibliography46C ISO 2012-All rights reservedIso16750-3:2012EForewordISo (the International Organization for Standardization) is a worldwide federation of national standardsbodies (Iso member bodies). The work of preparing International Standards is normally carried outthrough iso technical committees. Each member body interested in a subject for which a technicalcommittee has been established has the right to be represented on that committee. Internationaorganizations, governmental and non-governmental, in liaison with ISO, also take part in the workIso collaborates closely with the International Electrotechnical Commission (IEC) on all matters ofelectrotechnical standardizationInternational Standards are drafted in accordance with the rules given in the ISo/IEC Directives, Part 2The main task of technical committees is to prepare lnternational standards. draft InternationalStandards adopted by the technical committees are circulated to the member bodies for votingublication as an International Standard requires approval by at least 75 of the member bodiescasting a voteAttention is drawn to the possibility that some of the elements of this document may be the subject ofpatent rights. ISO shall not be held responsible for identifying any or all such patent rightsIso 16750-3 was prepared by Technical Committee ISO/TC 22, Road vehicle, Subcommittee SC 3,Electrical and electronical equipment.This third edition cancels and replaces the second edition (Iso 16750-3: 2007), which has beentechnically revisedISo 16750 consists of the following parts, under the general title road vehicles-Environmental conditionsand testing for electrical and electronic equipment:Part 1: GeneralPart 2: electrical loadsPart 3: Mechanical loadsPart 4: Climatic loadsPart 5: chemical loadso ISO 2012-All rights reservedINTERNATIONAL STANDARDIso16750-3:2012(E)Road vehicles- Environmental conditions and testing forelectrical and electronic equipmentPart 3Mechanical loads1 ScopeThis part of IS0 16750 applies to electric and electronic systems/components for road vehicles. Itdescribes the potential environmental stresses and specifies tests and requirements recommended forthe specific mounting location on/in the vehicleThis part of iso 16750 describes mechanical loads2 Normative referencesThe following referenced documents are indispensable for the application of this document. For datedreferences, only the edition cited applies For undated references, the latest edition of the referenceddocument (including any amendments applies.Iso16750-1, Road vehicles- Environmental conditions and testing forelectrical andelectronicequipment-Part 1: GeneralIEC 60068-2, 6, Environmental testing- Part 2-6: Testing, Test Fc: Vibration SinusoidalIEC60068-2, 14, Basicenvironmental testing procedures- Part 2-14: Tests-Test Nb: Change oftemperatureTEC 60068-2, 64, Environmental testing Part 2-64: Test methods -Test Fh -Vibration, broad-bandrandom(digital control)and guidanceIEC 60068-2, 80, Environmental testing- Part 2-80: Tests- Test Fi: Vibration - Mixed mode testingIEC 60068-2-31, Environmental testing procedures- Part 2: Tests; Test Ec: Free fall, Clause 5.23 Terms and definitionsFor the purposes of this document, the terms and definitions given in Iso 16750-1 app4 Tests and requirements4.1 Vibration41.1 GeneralThe vibration test metho ds specified consider various levels of vibration severities applicable to on-board electrical and electronic equipment. It is recommended that the vehicle manufacturer andsupplier choose the test method, the environmental temperature and vibration parameters dependingon the specific mounting locationFollowing the expressions in MIL-STD please noticeC ISO 2012-All rights reservedIso16750-3:2012EWhen applied properly, the environmental management and engineering processes described in this partof Iso 16750 can be of enormous value in generating confidence in the environmental worthiness andoverall durability. However, it is important to recognize that there are limitations inherent in laboratorytesting that make itimperative to use proper caution and engineering judgement when extrapolating theselaboratory results to results that may be obtained under actual service conditions. In many cases, realworld environmental stresses (singularly orin combination cannot be duplicated practically or reliably intestlaboratories. Therefore, users of this part of Iso 16750 should not assume that a system or componentthat passes laboratory tests of this part of Iso 16750 would also pass field/ fleet verification trialsThe specified values are the best estimation one can get up to the moment when results frommeasurements in the car are received - but they do not replace a car measurement!The specified values apply to direct mounting in defined mounting locations. Using a bracket formounting can resultin higher or lower loads. If the device under test ( DUT)is used in the vehicle with abracket then all vibration and mechanical shock test shall be done with this bracketCarry out the vibration with the dut suitably mounted on a vibration table. The mounting method (sused shall be noted in the test report. Carry out the frequency variation by logarithmic sweeping of 0,5octave/minute for sinusoidal tests and the sinusoidal part of sine on random tests. The scope of therecommended vibration tests is to avoid malfunctions and breakage mainly due to fatigue in the fieldTesting for wear has special requirements and is not covered in this part of ISo 16750Loads outside of the designated test frequency ranges are to be considered separatelNOTE Deviations from the load on the DUT can result, should vibration testing be carried out according tothis part of Iso 16750 on a heavy and bulky dut, as mounting rigidity and dynamic reaction on the vibrator tableexcitation are different compared to the situation in the vehicle. This deviation can be minimized by applying theaverage control method(see Annex A)Application of the weighted average control method according to IEC 60068-2, 64 is to be agreed uponSubject the dut during the vibration test to the temperature cycle according to iEC 60068-2, 14, withelectric operation according to diagram 1. Alternatively, a test at constant temperature may be agreed onOperate the dutelectrically as indicatedin Figure l at Tmin(Short functional testafterthe dUT completelyreached Tmin). This functional test shall be as short as possible- only long enough to check the properperformance of the dUt. This minimizes self-heating of the dUT. Additional electrical operation of theDUT between 210 min and 410 min of the cycle (see Figure 1)Additional drying of test chamber air is not permittedIn the vehicle, vibration stress can occur together with extremely low or high temperatures; for thisreason, this interaction between mechanical and temperature stress is simulated in the test, too. afailure mechanism is, for example, a plastic part of a system/component, which mellows due to the hightemperature and cannot withstand the acceleration under this condition2o ISO 2012-All rights reservedIso16750-3:2012[EYmax20aburditt0100200300400500600yY temperature[°C]x time [ minIa Operating mode 3.2 according to ISo 16750-1.b Operating mode 2. 1 according to ISo 16750-1One cycleFigure 1-Temperature profile for the vibration testTable 1- Temperature versus time for the vibration testTimeTemperaturemin°C0206040150-4021020300max41048020See Is016750-44.1.2 Tests4.1.2.1 Test I- Passenger car, engine4.1.2.1.1 PurposeThis test checks the dUt for malfunctions and breakage caused by vibrationThe vibrations of a piston engine can be split up into two kinds: Sinusoidal vibration which results from theunbalanced mass forces in the cylinders and random noise due to all other vibration-schemes of an engine,C ISO 2012-All rights reserved3Iso16750-3:2012Ee.g. closing of valves. In the lowest frequency range from 10 Hz to 100 Hz the influence of rough-roadconditions is taken into account. The main failure to be identified by this test is breakage due to fatigueNOTE 1 Road profile usually has negligible impact on engine-mounted components. Shock inputs are effectivelysolated by suspension, and engine-mounting systemsThe test profiles specified in the following clauses apply to loads generated by(four strokereciprocating enginesNotE 2 If the dut is to be tested for a specific resonance effect, then a resonance dwell test according to 8.3.2of IEC 60068-2, 6: 2007 can also be applied4.12.1.2Test4.1.2.1.2.1 GeneralIt is required to perform this test as a mixed mode vibration test according to IEC 60068-2, 80NOTE The test duration is based on A 4. The temperature in the chamher is above room temperature (rt)atthe end of the test (2 3/4 temperature cycles4.1.2.1.2.2 Sinusoidal vibrationPerform the test according to IEC 60068-2, 6, but using a sweep rate of s 0,5 octave/minute. Use a testduration of 22 h for each plane of the dUTUse curve l in Table 2/ Figure 2 for DUT intended for mounting on engines with 5 cylinders or fewerUse curve 2 in Table 2/Figure 2 for dUT test intended for mounting on engines with 6 cylinders or moreBoth curves may be combined to cover all engine types in one test2502001501005050100150200250300350400450500ⅩKeyamplitude of acceleration [m/s2IXfrequency [Hzcurve1(≤5 cylinders)curve 2(5 cylindersFigure 2- Vibration severity curves4o ISO 2012-All rights reservedIso16750-3:2012[ETable 2- values for max acceleration versus frequencyCurve 1(see Figure 2FrequencyAmplitude of accelerationHz100100200200240200270100440100Curve 2(see Figure 2)FrequencyAmplitude of accelerationHm/s2100100150150440150CombinationFrequencyAmplitude of accelerationH1001001501502002002402002551504401504,1.21.2.3 Random vibrationPerform the test according to IEC 60068-2, 64. Use a test duration of 22 h for each plane of the DUTThe r.m.s. acceleration value shall be 181 m/s2The psd versus frequency are referred to in Figure 3 and Table 3NoTE The Power Spectral Density(PSD)values (random vibration] are reduced in the frequency range of thesinusoidal vibration testC ISO 2012-All rights reserved5Iso16750-3:2012EY100100,110100100010000KeyY PSD [(m/s2)2/HzX frequency [Hz]Figure 3- PSD of acceleration versus frequencyTable 3- Values for frequency and PsDFrequencyPSDH:(m/s2)2/Hz1010100103000,5150020200024.1.2.1.3 RequirementBreakage shall not occur.Functional status a see iso 16750-1) is required during operating mode 3.2 as defined in ISo 16750-1and functional status C during periods with other operating modes4.1.2.2 Test II-Passenger car, gearbox4.1.2.2.1 PurposeThis test checks the dut for malfunctions and breakage caused by vibrationThe vibrations of a gearbox can be split up into two kinds which result partly from sinusoidal vibrationfrom unbalanced mass forces of the engine(e. g dominating orders) in the frequency range from 100 Hzto 440 Hz and vibration from the friction of the gear wheels and other schemes, which are tested in therandom part. In the lowest frequency range from 10 Hz to 100 Hz the influence of rough-road conditionsis taken into account The main failure to be identified by this test is breakage due to fatigueChanging the gears can create additional mechanical shock and shall be considered separatey brationsThe test profiles specified in the following subclauses apply to loads generated by gearbox vibo ISO 2012-All rights reserved

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LOGIO)测试、真有效值(TRMS)测量、相对值(REL〕测量、自动关机( AUTO OFF POWER)、当电流挡拔错位置时的声音告警等。国产VC90型数字万用表具有语音报数功能。MS8209型五合一数字万用表,还可以测量站空比(测量范围是0.1%~999%,误差为±3.0%)、温度(测量范围是-20~400℃C或-20~-1000℃,误差为±3.0%)、相对湿度(测量范围是30%-95%,误差为±5.0%)、照度(测量范围是4000~40000x,误差为±5.0%)及噪卢(测量范围是35~10UB)。VC9808A+增加了2000M超高阻挡,VC8145A还能测量功率电平。最新丌发的33/4位~412位智能数字万用表,将高性能与低成本集于一身,大多具有下述功能:液晶条图显示( LCD Baryaph),多重显示,测量最小偵/最大值,峰值保持:数据储存,复位,数据输出,设定测量范围的上、下限,软件自动校准,快速测量等。国产MS9803R型智能数字万用表采用光电隔离的RS232C接口,还配有 PC Windows视窗软件,能在PC上记录数据及输出图表。利用MS9803R所提供的 DMM VIEW Version2软件,将MS9803R拔至直流200m挡,并通过RS-232C接口连到PC上,实测某一缓慢变化的直流电压。测量范围宽:41/2位手持式多功能数字万用表为例,其测量范围一般为:DCV(001mV~1000V),ACV(0.01mV~700V或750V),DCA(0.1A~20A), ACA DCA(1A~20A),g2(0.0192-20Mg,少数仪表可达200M92,甚至扩展到2000192),电导(0.1nS~100nS),电容(0.1pF~20pF),电感(1H~20H),频率(10Hz-20kHz,部分仪表可达200kHz,甚至扩展到10MHz),二极管正向压降UF(0~2V),晶休管电流放大系数Hf(0-1000),可满足常规电了测量的需要。智能数字万用表的测量范围更宽。测量速率快:字万用表在每秒钟内对被测电压的测量速率,单位是“次/秒”。它主要取决于AD转换器的转换速率。有的手持式数字万用表用测量周期来表示测量的快慢。完成次测量过程所需要的时间叫测量周期。显见,测量速率愈高,测量周期就愈短,二者呈倒数关系。312位数字万用表的测量速率一般为2~5次秒,多数仪表为2~3次秒。41/2位数字万用表可达20次/秒。5/2位~71/2位数字万用表一般为几十次/秒以上,有的能达到几百甚至上千次秒。H3458A型81/2位DMM工作在41/2位方式下的最高测量速率可达10万次秒,在81/2位、51/2位方式下分别为6次秒、5万次秒。测量速率与准确度指标存在矛盾,通常是准确度愈高,测量速率愈低,二者难以兼顾。解这一矛盾有两种方法:一种是增设快速测量挡,专配测量速率交快的AD转挨器;另一种方法是通过降低显示位数来大幅度提高测量速率,此法目前应用的比较普遍,可满足不同用户对测量速率的需要时。输入阻抗髙:字万用表电压挡具有很高的输入阻抗,通常为10-10000MQ,从被测量电路上吸取的电流极小,不会影响被测信号源的工作状态,能减小由信号源内阻引起的测量误差。集成度高,微功耗:持式数字万用表采用单片AD转换器,外围电路比较简单,只要少量铺助芯片和外围元件。近年来各种单片数宇万用表专用芯片竟相问世,使用片IC即可构成功能比较完善的自动量程式数字万用表,为简化设计和降低成本创造了有利条件。新型数字万用表普遍釆用CMOS大规模集成电路的AD转换器,整机功耗很低。31/2312位数字万用表设计位、41门2位手持式数字万用表的整机功耗仅几十亳瓦,可用9V叠层电池供电。51/2位~812位数字万用表的总功耗一般也只有十至几十瓦。侏护功能完善,抗干扰功能强:字万用表具有比较完善的保护电路,过载能力强,新型数字万用表还增加了高压保护器件,能防止浪用电压。使用时只要不超过规定的极限指标,即使出现误操作(例如用电阻挡去测量220V交流电压),一般也不会损坏仪表内部的大规模集成电路。当然应力求避免误操作,以免因外围元件〔如熔丝管、量程开关)损坏而影响正常使用。必须指出,仼何保护电路都不可能做到万无一失。换言之,倘若保护保护电路发生故障,仪表就失去的保护屏障。51/2位以下的数字万月表大多采用积分式AD转换器,其串模抑制比(SMR)共模抑制比(CMR)分别可达100dB、80~120dB。高档数字万用表还采用数字滤波、浮地、双重屏蔽等先进技术,进一步提高了抗干扰能力,CMR可达180dB数字万用表应用于国防、科研、工厂、学校、计量测试等技术领域,并随着技术的发展,其性能不断提高。13论文设计的主要工作本次设计通过相关资料的收集及对数字万用表工作原理分析列出总体思路,采用ICL7106型多功能低功耗单片31/2位AD转换器,选择双积分AD转换方式,设计出交流电压测量电路、直流电流测量电路、电阻测量电路、电导测量电路、频窣测量电路、电容测量电路等。研究其每个参量的测量方法及功能实现。它主要的核心是通过AD转换来实现的,通过对测量电路的原理分析设计,实现交直流电压、直流电流、电阻、电容、晶体管等测量。此次设计的31/2位教字万用表显示清晰直观、读数准确,分辨力高、测试能力强、微功耗、外围电路简单、价格便宜、成本低等优点。2312位数字万用表的结构设计2.131/2位数字万用表基本构成数字万用表的基本构成如图2-1所示。仪表的心脏是单片AD转换器,典型产品有ICL7106、ICL7136型31/位单片A①转换器。外围电路主要包括功能转换器、测量项目及量程选择开关、LCD(或LED显示器)。此外还有蜂鸣器震荡电路、驱动电路、检测线路通断电路、低电压指示电路、小数点标识符、驱动电路。LU转换器LCD(LED)功能ACDC量程选择AD转换器数字电路诜择转换器Q/U转换器www.dola.com图2-1数字万用表基本构成Fig 2-1 The basic component of ordinary digital multimeter2,2功能转换器的介绍及基本工作原理尽管数字万用表的型号繁多,整机电路也各有差异,但其基本测量原理大致相同。下面介绍数字万用表最常用的几种功能转换器的电路工作原理,对于本次数字万用表设计原理与应用具有重要的意义22.1线性ACDC转换器数字万用表的交流/直流(ACDC)转换器分平均值响应的AC/DC转换器、真有效值/直流( TRMS/DO)转换器两种平均值响应的线性ACDC转换器是由运算放大器和二极管组成的半波(或全波)线312位数字万用表设计性整流电路。它具有线性好、准确度髙、电路简单、成本低廉等优点。由于它是按照正弦波平均值与有效值的关系而定的,因此所构成的仪表只适用于测量不失真的止弦波电压线性全波整流式ACDC转换器的电路图如22所。交流电压满量程为200mV(有效值)现利用单运放TI61(IC1)与二极管T、D2组成平均值响应的线性整流电路,能消除二极管在小信号整流时所引起的非线性电压,使输出的平均值电压U与ACDC转换器的输入电压UN(有效值)呈线行关系,适合测量40~400Hz的正弦波,测量准确度优于1%。当频率超过400H时,测量误差会增大。电路中的R是T061同相输入端电阻。R2与R3为负反馈电阻,可将IC接成同相放大器。C1、C2为隔直电容TH(UM=20m)10OkC1L, NL01 47uU o R7 1MIN+160.02217106UD2 ILCD. 8K00k3K32RPCOM1D3R6200187K图22 AC/DC转换器的电路comFig 2-2 The circuit of the AC/DC Converters需要指出,该电路属于输出不对称式线性全波整流电路,在正、负半周时的等效电路及整沆输出波形如图23所示。正半周时电压放大倍数K>222(半波整流时正弦波的有效值与平均值的关系为UR=2.22U0);负半周时Kr=1,它相当于电压跟随器。具体讲,在正半周时v1导通,D2截止,IC1输出电流的途径是C1→VD1→R4→R6一RP→COM(地),并终过R3对C3充电。此时式中R电位器RP的电阻值。将R4=3k2,、R6=1,87k2、R2p=0~2002代入上试得到K=2.6~245>2.22。负半周时,VD2导通,V1截止,电流途径变成COM→RP→R6→D2→C1→C1,此时K=1。由R和IClRI[C1o UoR4VD?图2-3等效电路及输出波形Fig 2-3 Equivalent circuit and the output waveformC组成的平滑滤波器可滤除交流纹波,高频千扰信号则被由R、C构成的高频滤波器所滤掉,从而获得了稳定的平均值电压,再通过312位单片AD转换器IC2(ICL7106)完成数/模转换,驱动LCD显示出测试结果。图2-2中的阴影区表示连接AD转换器与LCD的导电橡胶条。该电路能消除整流管的非线性误差。RP是校准交流电压的电位器,调整RP可使仪表直接显示出被测电压的有效值。C是运放IC的频率补偿电容。R2和C4还向VD2提供偏压,以减小TL061对小信号放大时的波形失真。TL061的电源亦可取自9V电源。上述ACDC转换器适配各种31/2~412位单片AD转换器,并可将LCD改成LED显示器。设计交流电压挡(ACV)时,还应在ACDC转换器的输入端接上如图22中所示的精密电阻分压器R1~R222简易平均值AC①C转换器简易平均值ACDC转换器的电路图2-4所示。由于该电路末使用运算放大器及电位器,因此电路简单,不需要调整。两个ACV挡分别为200V、750V(RMS)。VD为整流管,VD2为保护二极管。R1为输入端电阻,仪表输入阻抗∠≈R=R1+R2+R32=4.51M。C1为隔育电容。正半周时四导通,VD2截止,做半波整流;负半周时T1截止,四D2导通,由VD2给电流提供泻放回路。整流后的脉动直流经C2滤波,获得平均值电压Uo。R2和R3为滤波器312位数字万用表设计负载,兼作750V拦的分压器,可将U再衰减10倍。ACⅤ挡的测量准确度可达±1.2%~士15%,误差略高于线性整流电路。D和V2应采用N4004型1A400ⅴ的硅整流管,以便承受较高的反向电压。对半波整流而言,正弦波电压平均值与有效值的关系为U=045Uw。巧妙地利用电阻分压器可使仪表直接显示被测电压有效值。不难验证,对于200V挡,若UN=2000V(RMS),则Jl=0.45U/m=0.45×200.0V=90V10×103=0R2+R3=90My200. 0mvR1+R2+R24.51×10°1 CI VDI200VIN+4.5M0.1μR27106750VU.F200mACvLCDVD2本Tc2IN4004Ou hR30.022COMO1KCOM图24简易平均值ACDC转换器电路Fig, 2-4 The circuit of simple average of ac/ dc 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