ISO16750-3-2012
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
- 2020-12-08下载
- 积分：1
基于LabVIEW的数据采集与处理技术
labview编程 基于LabVIEW的数据采集与处理技术 白云 高育鹏922 LabsQL的安装及配置…185102.1 Labview中的数字仿真简介…20392.3 LabsQLⅥ模块及使用方法……1871022 LabvIew中的数字仿真本章小结.201算法模块203练习与思考…本章小结…215第10章 LabviEw与仿真技术…02练习与思考21610.1仿真技术概述…02参考文献…21710.2LabⅤIEW中的数字仿真…203第1章虚拟仪器技术命器DDC第1章虚拟仪器技术NICFS-C3器好,来案是1.1虚拟仪器概述萨好14器外口约D1.11虚拟仪器的基本概念所谓虚拟仪器 Virtual instrument,Vm,是指以通用计算机作为系统控制器,由软件来实现人机交互和大部分仪器功能的」种计算机仪器系统。用户操作这台通用计算机就像操作一台为自己专门设计的传统电子仪器样。虚拟仪器的出现,使得测量仪器与计算机之间的界线逐渐模糊。总虚拟仪器通过o接口设备完成信号的调理、采集与测量,利用个人计算机强大的软件功能实现信号数据的运算、分析、处理,由个人计算机显示器模拟传统仪器的控制面板,以多种形式输出检测结果,从而完成各种测试功能。“虚拟”二字主要包含以下两方面含义:(1)虚拟仪器的面板是虚拟的。虚拟仪器面板上的各种“控件”与传统仪器面板上的各种“器件”所完成的功能是相同的。程传统仪器面板上的器件都是实物,需要通过手动或触摸进行操作;而在虚拟仪器中,物理的开关、按键等器件均由与实物外观相似的图形控件来代替,它们分别对应着相应的软件程序。这些程序是已设计好的,用户可直接通过鼠标或键盘操纵这些控件来完成对仪()虚拟仪器的测量功能是由软件编程来实现的。在虚拟仪器系统中,硬件仅仅用来处的操控n101i理信号的输入输出,软件才是整个测试仪器系统的关键。用户可以通过软件编程来实现仪器的测试功能,还可以通过组合不同测试功能的软件模块来实现多种测试功能。当测试要求发生变化或者需要增加(减少)测试项目时,用户只需要适当地更改软件程序,即可生成满足测试要求的全新的测试仪器系统。因此,在硬件平台确定后,有着“软件就是仪器”的说法,它体现了测试技术与计算机深层次的结合。壁1.1.2虚拟仪器的构成从内部功能来讲,虛拟仪器与传统仪器一样,均由数据采集与控制、数据分析与处理及结果显示三部分组成,如图1-1所示。以总的游关样其平南OM的,对,当的器外,中亲2基于 LabVIew的数据采集与处理技术采集与控制数据分析与处理结果显示插入式数据采集板数字信号处理网络通信GPB仪器数字滤波硬盘拷贝输出XPX仪器统计分析文件10RS232仪器数值分析用户图形接口图1-1虚拟仪器的内部功能划分从构成要素来讲,虚拟仪器由硬件系统和软件系统两大部分组成,如图1-2所示。硬件系统软件系统广============--------------------=信号调理数据采集卡GPI接口仪器GPIB接口卡应用软件|仪器是加1.1,1串行接口仪器仪器个被通|s器功对测对 VXUPXI仪器用计算/能动应人机程用长合现场总线设备用P回过大管计个图像釆集、数字信号处理件上虛户拟下中舍面其他硬件模块板示释等外围硬件设备向面流器进重()图1-2虚拟仪器的系统构成回的雨“器1.虚拟仪器的硬件系统集干要,求景器书器的避面器虚拟仪器的硬件系统通常包括通用计算机和外围硬件设备。其中,通用计算机可以是笔记本电脑、台式机或工作站等。外围硬件设备可分为GB( General Purpose Interface Bus)VXI(VMEbus eXtension for Instrumentation), PXI(PCI eXtension for Instrumentation) FLDAQ( ata Acquisition)四种标准体系结构。构成系统时,可以选择单一的,也可以选择由两种或两种以上硬件系统构成的混合系统。其中,最简单、最廉价的形式是采用ISA或PCI总线的数据采集卡,或是基于RS-232或USB总线的便携式数据采集模块2.虚拟仪器的软件系统平合虚拟仪器的软件系统从底层到顶层共包括三部分,即vSA(O)库、仪器驱动程序与应用软件。1)ⅤISA库的器VISACVirtual Instrumentation Software Architecture即虚拟仪器软件体系结构,实质是标准的IO函数库及其相关规范的总称。一般称这个LO函数库为VSA库,它驻留于计算机系统之中,执行仪器总线的特殊功能,是计算机与仪器之间的软件层连接,可实现对仪器第1章虚拟仪器技术13的程控。对于仪器驱动程序开发者来说,它是一个个可调用的操作函数集。不2)仪器驱动程序仪器驱动程序是完成对某一特定仪器控制与通信的软件程序集,它是应用程序实现仪器控制的桥梁。每个仪器模块都有自己的仪器驱动程序,仪器厂商将仪器驱动程序以源码的形式提供给用户。D情总分能器对期干善。高研善淀3)应用软件应用软件建立在仪器驱动程序之上,直接面对操作用户。它通过直观、友好的测控操作界面,丰富的数据分析与处理功能,来完成自动测试任务。虚拟仪器应用软件的编写大致可分为两种方式:总面(1)用通用编程软件进行编写。通用编程软件主要有 Microsof公司的Ⅴ sual Basic与Visual c++、 Borland公司的 Delphi、 Sybase公司的 PowerBuilder等(2)用专业图形化编程软件进行开发。专业图形化编程软件如HP公司的VE、NI公司的 Lab vIew和 Lab windows/CⅥ等应用软件还包括通用数字处理软件,它主要由用于数字信号处理的各种功能函数(如频域分析的功率谱估计、FFT、FHT、逆FFT、逆FH和细化分析等;时域分析的相关分析卷积运算、反卷运算、均方根估计、差分积分运算和排序等)及数字滤波等部分组成。这些功能函数为用户进一步扩展虚拟仪器的功能奠定了基础113虚拟仪器的特点14虚拟仪器具有如下六个特点1)突出“软件就是仪器”的新概念,用户可自定义测量功能在通用硬件平台确定后,可由软件取代传统仪器中的硬件来完成仪器的功能。软件的灵活性和复用性使用户可以按自己的需要定义(设置测量功能,这就给用户提供了一个充分发挥自己能力和想象力的空间。2)强大的数据处理功能。虚拟仪器将信号分析、显示、存储、打印和其他管理交由计算机来集中处理,充分利用了计算机强大的数据处理、传输和发布功能。信号处理理论的不断完善以及计算机运算速度的大大提高,为虚拟仪器快速、准确地处理数据提供了良好的基础。(3)灵活性和可扩展性强,性价比高,便于组成复杂的测试系统。当希望测试系统增加个新的测量功能时,只需通过增加软件来执行新的功能或增加一个通用模块来扩展系统的测量范围;为提高测试系统的性能,可以通过加入一个通用仪器卡或更实现,这样有利于系统的扩展,也可大大节约购买和维护仪器的费用(4)良好的人机界面。虚拟仪器的操控界面是一种虚拟面板,亦称为软面板。虚拟面板可以模拟传统仪器面板的风格来设计,也可以由用户根据实际需求自行设计。测量结果可以通过计算机显示器以曲线、图形数据或表格等形式方便灵活地显示出来。(5)与其他设备互连的能力强。虚拟仪器通常具有标准化的总线或通信接口,具有与其他设备互连的能力。近年来,随着网络技术的发展,已经形成了网络虚拟仪器。这是一种新型的基于Web技术的虚拟仪器,它使得虚拟仪器测试系统成为 Internet/Intranet的一部分,可实现远程测试、监控和故障诊断等功能,以便充分利用有效资源,提高测试效率(6)技术更新快。由于虚拟仪器技术是建立在当今世界最新的计算机技术、数据采集技4基于 Labview的数据采集与处理技术术和通信技术基础上的,因而技术更新速度快于传统仪器。界搭对干,登路器界(S1.14虚拟仪器接口总线技术器对宝一某量平器为随着计算机技术、测试仪器和测试技术的不断发展,虚拟仪器接口总线技术也得到了不断的完善和提高。目前用于虚拟仪器和测试系统的总线技术有GPIB总线、VX总线、PX总线、IEEE1394总线和USB总线等。科(1.GPB总线,器器为立游GPB在20世纪70年代由惠普公司率先提出,经批准后成为IEE488标准,是业界所接受的第一个程控通用仪器总线。GPIB包括IEEE4881-1978标准和IEEE4882-1987标准两部分,前者定义了硬件标准,后者则定义了软件标准。GPB总线接口有24线(EE488标准)和25线(IEC-625标准)两种形式,其中以IEEE488的24线GPB总线接口应用最多在我国,国家标准中规定采用24线的电缆及相应的插头插座。如今,GPB已经成为计算机与仪器间最通用的总线标准。由于历史悠久,GPIB具有广泛的软/硬件支持,几乎所有的独立仪器都配有GPIB接口。因GPIB的最大带宽为18Mbs(最新的高速版HS488更是将最大带宽提高到了8Mb/s,所以最为适合与分立仪器通信,并对分立仪器进行控制。GPB中的数据传递采用基于信息的通信模式,并常使用 AScII字符。北用长典型的GPIB测试系统包括一台计算机、一块GPIB接口卡和若干台GPIB仪器,其总距为20m,带宽为总线上的所有仪器共享。GPIB测试系统的仪器之间可采用总线型连接或星型连接,如图1-3所示。每台GPIB仪器有单独的地址,由计算机控制操作。整个测试系统中的仪器若要增加、减少或更换,只需对计算机的控制软件做相应改动即可。中升如柱(置如)义宝要害x的大资,里中果来时出于,卦活仪器A仪器C仪器A仪器B仪器D仪器C仪器B不是探(a)图1-3GPB测试系统仪器间的连接方式界益为(a)仪器间采用总线型连接;(b)仪器间采用星型连接」甲第1章虚拟仪器技术」-5GPIB测试系统的结构和命令简单,有专为仪器控制所设计的接口信号和接口插件,具有突出的坚固性和可靠性。网络上也有各种GPHB驱动,因而具有较好的兼容性。GPIB适用于现有的自动化测试设备、混合测控系统和有特殊要求的专用仪器系统。GPIB的缺点是无法提供多台仪器同步和触发的功能,在传输大量数据时带宽不足。前目率解卦目2.V总线日(2 uH Lense IBas in)a2uwx即ME总线在仪器领域的扩展,它于1987年,由主要仪器制造商在ⅥE总线Eurocard标准(机械结构标准)和EE488等基础上,共同制定的开放性仪器总线标准。目前,国际上有两个VX总线组织:一是VⅪ联盟,负责制定vXI的硬件(仪器级标准规范,包括机箱背板总线、电源分布、冷却系统、“0槽”模块、仪器模块的电气特性、机械特性电磁兼容性以及系统资源管理和通信规程等内容;二是vX总线即插即用vxPg&Pay,vP系统联盟,宗旨是通过制定一系列VX的软件系统级标准来提供一个开放性的系统结构,真正实现ⅴXT总线产品的“即插即用”。这两套标准组成了VXI标准体系,实现了VXI的模块化、系列化、通用化,提高了vX仪器的互换性和互操作性。E1VX系统最多可包含256个装置,主要由主机箱、“0槽”控制器、具有多种功能的模块仪器和驱动软件、系统应用软件等组成。系统中各功能模块可随意更换,即插即用,可组成新系统。1998年,VⅪI20版采用了VME总线的最新扩展技术,提供有64位的扩展能力,数据传输率可达80Mbs,而且经过段时间的努力,VⅪI总线系统已成功地应用于微波频段。目前,可用的VⅪI仪器已有将近2000种,并还在以每年150~200种的速度增加,基本上可以满足绝大多数VXI系统的需要。1X,1MO0C,mis2m由于ⅴⅪI的价格相对较高,而且许多GPIB仪器还能满足实际的需要,再则在集成XI系统时,需要有系统设计能力、系统调试经验、误差分析修正定标、校准技术及测试程序开发能力,因此ⅴⅪI仪器的使用和推广受到了一定的限制。目前,VXI主要应用于国防、航空航天、通信以及其他需要高性能、高质量、大批量产品的生产环境或实验室及研究开发中。回计,到为类,中时测交,器由积封主3.PX总线未站以1即法原以,重下DPⅪI是PCI在仪器领域的扩展,N公司于199年发布的一种新的开放性、模块化仪器总线规范,其核心是 CompactPCI结构和 Microsoft windows软件。PⅪ是在PCI内核技术上增加了成熟的技术规范和要求而形成的。PXI增加了用于多板同步的触发总线和参考时钟、用于精确定时的星型触发总线以及用于相邻模块间高速通信的局部总线等,以满足试验和测量用户的要求。PⅪI兼容 CompactPCI机械规范,并增加了主动冷却、环境测试(温度、湿度、振动和冲击试验等要求。这样,可保证多厂商产品的互操作性和系统的易集成性。与ⅴⅪI模块相比,PⅫⅪ模块体积更小、传输速率更高、价格也较便宜,而且组建一个PX系统要比ⅴX系统简单。PX与台式机的区别在于,Px将计算机和插卡式仪器模块安装在带有许多护展槽的工业机机箱中。从软件角度上说,安装个PⅪ模块就像在台式机上安装一块PC卡,PXI模块作为标准的即插即用PCI器件能被自动识别和设置,并配置有相应的 Windows驱动程序。由于PXI和主流计算机技术完全兼容,因此在许多测试领域,由台式机组成的系统与PX系统可以相互替代,而且PX1系统在性能上还远远超过了台式机。,的d3W6甚于 LabVIEw的数据采集与处理技术4.USB总线和E1394总线独速UsB总线和IEE1394总线是日前广泛使用的两种总线接口,它们支持热插拔,可以自动识别、自动组态,实现即插即用。与并行总线比较,它们更适合连接多外设的需要,且传输速率高,目前已有一些测量仪器使用了这两种总线,回器合费USB( Universal serial Bus)主要用来连接外围设备,如键盘、扫描仪、磁盘机等。苹果电脑率先于1998年使用USB做为其唯一的串口,目前在PC机上已被广泛使用。由于其即插即用的易用性和USB20高达480Mbs的传输速率,USB总线已逐渐成为仪器控制的主流总线技术。USB总线只有一对信号线和一对电源线,轻巧简便、价格便宣,能连接127个装置。现在计算机上的USB接口越来越多,这使得工程师可以很方便地将基于USB的测量仪器连接到整个系统中。但是USB在仪器控制方面亦有一些缺点。比如说USB的排线没有工业标准的规格,在恶劣的环境下,可能造成数据的丢失;此外,USB对排线的距离也有一定的限制。1如到IEEE1394总线又称火线总线,是苹果电脑公司于1989年设计的高性能串行总线,目前的标准为IEEE1394-1995。IEE1394总线的传输速率为100Mb/s、200Mbs、400Mb/s,甚至可以达到32Gbs。EE1394总线具有两对信号线和一对电源线,可采用任意方式连接63个装置。当两M建0.D,e1,亲边5.其他总线15直,2M08率,(3安捷伦科技和ⅴ XI Technology公司于2004年推出了LXI( LAN eXtensions forInstrumentation)总线。2004年11月,LX联盟 LXI Consortium成立,旨在开发、支持和促进LXI标准。2005年9月,LX联盟正式公布了LXI1.0标准。2006年第一季度首批通过LXT认证的产品即被推出。,课为图要箭相溶LXI基于IEEE8023以太网技术,是以太网在仪器领域的扩展。LXI总线速度现在最快达到千兆位每秒,还将发展为万兆位每秒。LXI理论上支持的设备数目不受限制,并且通过使用路由器、交换机和中继器,对线缆长度几乎没有限制,还可以使用无线局域网技术LXI不受地理限制,可以实现远程测量应用。LXI被认为在未来将取代GPB,但相比GPIB,LXI还存在一定的延迟问题。T公1A,的器1除了上述几种总线技术外,虚拟仪器还广泛采用其他的总线,如RS232C、标准并行接口( Standard parallel port,SPP)、增强型并行接口( Enhanced parallel port,EPP)以及以太网Etherne等。用户可根据自己的实际情况选用适当的产品。修下12虚拟仪器技术前景展望虚拟仪器技术经过二十多年的发展,正沿着总线与驱动程序标准化、软硬件模块化,以及编程平台图形化和硬件模块即插即用(Plug&Pay)化等方向发展。其发展前景主要体现在以下几方面:部(1)开放式数据采集标准将使虚拟仪器走上标准化、通用化、系列化和模块化的道路。(2)数据采集产品性能的不断提高,为测试技术水平的提高提供了可靠的保证。3)随着Web技术的迅猛发展,以及它与虚拟仪器技术的结合,会形成基于web技术第1章虚拟仪器技术7的虚拟仪器。新一代的虚拟仪器将能够快速、方便地与蓝牙、无线以太网和其他标准的网络技术相融。“网络即仪器”也将成为新的概念,而网络化仪器必将推动仪器界新的革命。基十本章小结9本章简要介绍了虚拟仪器的基本概念、构成、特点以及虚拟仪器接口总线技术。通过本章的学习,希望读者能够对虚拟仪器及接口总线技术有一个总体的了解,以便于以后进一步的学习。9圈登图小型“点,天个行计的练习与思考一1浪求,米得的到中已样11.什么是虚拟仪器?简述虚拟仪器的组成及特点。出烟显读十贵的2.虚拟仪器主要采用哪些总线接口技术?它们各有什么优、缺点?装量,的出中量实同世个部量,的为实出果声面真对人1容内频,景的具个1)求来清置西公胃到的翻首应中亲长蛙道,( OAU.TOUPPIUDA里处没变面小的早中出人解的早滑由,长过文,团是个。当出求合一溶内内善外出非料,A,更应翅器计,中差,书一分中机:卧申名方,量中面平,界近否,图宾动结上米限个示显的律,两长过销题自中个发西眼实世量(离,试科平中强(2等来中C图头中紫计要最,平无,之上其,平的,的一,长为,只的更,过1要果,类,深菱人,中题,限回单首算出,型米
- 2021-05-06下载
- 积分：1
