abaqus script reference manual
ABAQUS脚本参考文件，适合二次开发，ABAQUS各个模块的语句参考ABAQUS Offices and RepresentativesABAQUS, IncABAQUS Europe BVRising Sun millsGaetano Martinolaan 95166 Valley streetP.O. BOx 1637Providence RI 02909-24996201 BP MaastrichtTel:+14012764400The netherlandsFax:+14012764408Tel:+31433566906E-mail:support(@abaqus.comFax:+31433566908http://www.abaqus.comE-mail:info.europe@abaqus.comSales, Support, and ServicesUNITED STATESABAQUS Central, IncABAQUS East LLC1440 Innovation place300 Centerville road. Suite 209WWest Lafayette, IN 47906-1000Warwick. RI 02886-0201Iel:+17654971373Tel:+14017393637Fax:+17654974444Fax:+14017393302E-mail:support(@abaqusCentral.comE-mail: support@ abaqus EastcomAbAqUS Erie. incABAQUS Great Lakes, Inc3601 Green Road. Suite 31614500 Sheldon road. Suite 160Beachwood. OH 44122Plymouth, MI 48170-2408Tel:+12163781070Tel:+17344510217ax:+1216378107F7344510458E-mail:support(@abaqusErie.comE-mail:support(@abaqusGreatlakes.comABAQUS South, IncABAQUS West, Inc3700 Forums Drive Suite 10139221 Paseo Padre Parkway Suite FFlower Mound. TX 75028remont, CA 94538-1611Tel:+12145131600Tel:+15107945891Fax:+12145131700Fax:+15107941194F-mail:support(@abaqusSouth.comF-mail:supportabaqusWest.comARGENTINAAUSTRALIAKB Engineering S.R. LWorley Advanced analysisFlorida 274-Oficina 35Level 17. 300 Flinders Street1005 Buenos airesMelbourne Vic 3000ArgentinaTel:+61386125132Iel:+541143269176/7542Fax:+61392050573Fax:+541143262424E-mail:abaqus@worley.com.auE-mail: sanchezsarmientoarnet com arAUSTRIABENELUXABAQUS AuStria GmbHABAQUS Benelux EⅤZinckgasse 20-22/2/13Huizermaatweg 576A-1150 Vienna1276 LN HuizenaustriaThe NetherlandTel:+4319291625-0Tcl:+31355258424Fax:+4319291625-20Fax:+31355244257E-mail: support @abaqus.atE-mail: support(abaqus. nlCHINACZECH REPUBLICABAQUS ChinaSynerma s.r.oRoom a-2703 Eagle plazaHuntirov 58No. 26 Xiao yun rd468 22 SkuhrovBeijing, 100016Czech republicP.R. ChinaTel:+420603145769Tel:+860184580366Fax:+420603181944Fax:+860184580360E-mail: abaqus asynerma czE-mail:abaqus(@abaqus.com.cnFRANCEGERMANY(Aachen)ABAQUS France SasABAQUS Deutschland gmbH7 rue jean MMermozBat. aTheaterstrabe 30-3278000 VersaillesD-52062 AachenIel:+330139241540lel:+49241474010Fax:+330139241545Fax:+492414090963E-mail: support (@abaqus. frEmail: info(abaqus.deGERMANY(Munich)INDIA(Chennai)ABAOUS Deutschland gmbhABAQUS Engineering India(Pvt. LtdSendlinger-Tor -platz 83M. Prince arcadeD-80336 Munchen22-A Cathedral roadTel:+498959991768Chennai. 600086Fax:+498959991767Tel:+914428114624E-mail: info(abaqus.deFax:+914428115087E-mail: abaqus(@abaqus.coinITALYJAPAN(Tokyo)ABAQUS Italia s r IABAQUs. IncVia domodossola. 173rd Floor, Akasaka Nihon Building20145 Milano(MD)5-24, Akasaka 9-chome, Minato-kuTel:+390239211211Tokyo,107-0052Fax:+390231800064Tcl:+81354745817E-mail: info(@abaqus.itFax:+81354745818E-mail: tokyo(abaqus. jpJAPAN (Osaka)KOREAABAQUS, IncABAQUS Korea. Inc9th Floor, Higobashi Watanabe BuildingSuite 306, Sambo Building6-10. Edobori 1-chome Nishi-ku13-2 Yoido-Dong, Youngdeungpo-kuOsaka.550-0002Seoul.150-010Tel:+81648035020Tel:+8227856707Fax:+81648035021Fax:+8227856709E-mail: osaka @abaqus. jpE-mail: info(@abaqus. co kIMALAYSIANEW ZEALANDWorley advanced AnalysisMatrix Applied Computing Ltd19th Floor, Empire TowerP.O. Box 56-316. AucklandCity square centreCourier: Unit 2-5, 72 Dominion road Mt eden182 Jalan Tun razakauckland50400 Kuala LumpurTel:+6496231223Tel:+6032161226Fax:+6496231134Fax:+60321614266E-mail: abaqus-tech(amatrix co nzE-mail:abaqusmy@worley.com.auPOLANDRUSSIA, BELARUS UKRAINEBudSoft sp. z0.0TESIS Ltd61-807 PoznanOffice701-703,Sw Marcin 58/64l8. Unnatoy strIe:+486l8508466127083 Moscow. RussiaFax:+486l8508467Tel:+7095212-44-22E-mail:budsoft@budsoft.com.plFax:+7095212-42-62E-mail:infoatesis.com.ruSINGAPORESOUTH AFRICAWorley Advanced AnalysisFinite Element analysis Services (Ply)Ltd491B River valley roadUnit 4, The Waverley#09-01Ⅴ alley pointWyecroft roadSingapore, 248373Mowbray 7700Tel:+6567358444Tel:+27214487608Fax:+6567357444Fax:+27214487679E-mail:abaqus.sg@worley.com.auE-mail: feas(afeas co zaSPAINSWEDENPrincipia Ingenieros Consultores, SAABAQUS Scandinaviavelazquez, 94FEM-Tech ABE-28006 MadridPilgatan &cIel:+34912091482SE-72130 VasterasFax:+34915751026Tcl:+4621126410E-mail: abaqus(principia. esFax:+4621181244E-mail: abaqus abaqus.seTAIWANTHAILANDAPICWorley Advanced Analysis11F, No. 71, Sung Chiang road333 Lao Peng Nguan l BuildingTaipei. 1042820th Floor Unit bIel:+8860225083066Soi ChaypuangFax:+8860225077185Vibhavadi-Rangsit roadE-mail:apicaapic.com.twLadyao, JatujakBangkok 10900Tel:+6626893000Fax:+6626188109E-mail:abaqusth(@worley.com.auTURKEYUNITED KINGDOM(Cheshire)A-Ztech ltdABAQUS UK LtdPerdemsac Plaza, Teknoloji eviThe Genesis CentreBayar Cad, Gulbahar Sok., No: 17Science park south BirchwoodKozyataWarrington Cheshire WA3 7BH34742 IstanbulTel:+441925810166TURKIYEFax:+441925810178Tel:+902163618850E-mail: hotline abaqus. co ukFax:+90216361885E-mail:info(aa-ztech.com.tiSales OnlUNITED STATESABAOUS EaSt llc. mid-Atlantic officeABAOUS SOUth. Inc. Southeast office1 1 4 Zachary Court484 Broadstone wayForest hilL. MD 21050Acworth.GA30101lel:+14104208587lel:+17707950960Fax:+14104208908Fax:+17707957614E-mail:support(@abaquseast.comE-mail:support(@AbaqusSouth.comABAQUS West, Inc, Southern CA and Az Office ABAQUS West, Inc, Rocky Mountains Office1100 Irvine boulevard #2486910 Cordwood CtTustin Ca 92780Boulder co 80301Iel:+17147315895Tel:+13036645444Fax:+17142427002Fax:+1303200948lE-mail:inFo(aabaqusWest.comE-mail:Into(aabaqusWest.comFINLANDINDIA (Pune)ABAQUS Finland OyABAQUS Engineering Analysis Solutions(Pvt. LtdTekniikantie 12C-9. 3rd FloorFIN-02150 EspooBramha Estate, Kondwa roadTel:+358925172973Pune-411040Fax:+358925172200Tel:+912030913739F-mail: abaqus(@abaqus.seF-mail: abaqus( abaqus. co inUNITED KINGDOM(Kent)ABAOUS UK LtdGreat hollander business centre. Unit aMill Lane. UnderriverSevenoaks, Kent tN15 OSQTel:+441732834930Fax:+441732834720E-mail: hotline(abaqus. co ukPrefaceThis section lists various resources that are available for help with using ABAQUS, including technicalengineering and systems support, training seminars, and documentationSupportABAQUS, Inc, offers both technical engineering support and systems support for ABAQUS. Technicalengineering and systems support are provided through the nearest local support office. You can contactour offices by telephone, fax, electronic mail, the ABAQUs web-based support system, or regular mailInformation on how to contact each office is listed in the front of each ABAQUS manual. The ABAQUSOnline Support System(AOSS) is accessible through the MY ABAQUS section of the ABAQUS HomePage(www.abaqus.com).Whencontactingyourlocalsupportofficespleasespecifywhetheryouwouldlike technical engineering support (you have encountered problems performing an ABAQUS analysis orcreating a model in ABAQUS) or systems support (ABAQUS will not install correctly, licensing does notwork correctly, or other hardware-related issues have arisenThe ABAQUS Online Support System has a knowledge database of ABAQUS Answers. The ABAQUSAns wers are solutions to questions that we have had to answer or guidelines on how to use ABAQUS. Wewelcome any suggestions for improvements to the support program or documentation. We will ensure thatany enhancement requests you make are considered for future releases. If you wish to file a complaint aboutthe service or products provided by aBaqUs, refer to the aBaQus Home PageTechnical engineering supportABAQUS technical support engineers can assist in clarifying ABAQUS features and checking errors by givingboth general information on using ABAQUS and information on its application to specific analyses. If youhave concerns about an analysis, we suggest that you contact us at an early stage, since it is usually easier tosolve problems at the beginning of a project rather than trying to correct an analysis at the end.Please have the following information ready before calling the technical engineering support hotline, andinclude it in any written contacts:Your site identifier, which can be obtained by typing abaqus whereami at your system prompt(or byselecting Help-On Version from the main menu bar in ABAQUS/CAE or ABAQUS/Viewer)· The version of△ BAQUS that are you usingThe version numbers for ABaQUS/Standard and ABAQUS/Explicit are given at the top of the data(. dat)fileThe version numbers for ABAQUS/CAE and ABAQUS/Viewer can be found by selectingHelp-On Version from the main menu bar.The version numbers for the abaqus Interface for MoldFLOW and the abaQus Interface forMSC ADAMS are output to the screenThe version number for ABAQUS for CAtIa V5 can be found by selecting Help-AboutABAQUS for CaTiA V5 from the main menu bar in either of the aBaqus for CAtIA V5workbenchesThe type of computer on which you are running ABAQUSThe symptoms of any problems, including the exact error messages, if anyWorkarounds or tests that you have already triedWhen calling for support about a specific problem, any available abaqus output files may be helpful inanswering questions that the support engineer may ask youThe support engineer will try to diagnose your problem from the model description and a description ofthe difficulties you are having. The support engineer may need model sketches, which can be sent via fae-mail, or regular mail. Plots of the final results or the results near the point that the analysis terminated mayalso be needed to understand what may have caused the problemIf the support engineer cannot diagnose your problem from this information, you may be asked tosupply the input data. The data can be attached to a support incident in the aBaQUS Online SupportSystem. It may also be sent by means of e-mail, tape, disk, or ftp Please check the ABAQUS Home Page(http://www.abaquscom)forthemediaformatsthatarecurrentlyacceptedAll support incidents are tracked in the abaQUs Online Support System. This enables you( as well asthe support engineer) to monitor the progress of a particular problem and to check that we are resolving supportissues efficiently. To use the ABAQUS Online Support System, you need to register with the system. Visit theMY ABAQUS Section of the ABAQUS Home Page for instructions on how to register. If you are contactingus by means outside the aoss to discuss an existing support problem and you know the incident number,please mention it so that we can consult the database to see what the latest action has been and, thus, giveyou more efficient support as well as avoid duplication of effort. In addition, please give the receptionist thesupport engineers name if contacting us via telephone or include it at the top of any e-mail correspondenceSystems supportABAQUS SyStems support engineers can help you resolve issues related to the installation and running ofABAQUS, including licensing difficulties, that are not covered by technical engineering supportYou should install ABaQUS by carefully following the instructions in the ABAQUS Installation andLicensing Guide If you are able to complete the installation, please make sure that the product verificationprocedure was run successfully at the end of the installation procedure. Successful verification for licensedproducts would indicate that you can run these products on your computer; unsuccessful verification forlicensed products indicates problems with the installation or licensing (or both ) If you encounter problemswith the installation, licensing, or verification, first review the instructions in the abaQus Installation andLicensing Guide to ensure that they have been followed correctly. If this does not resolve the problems,consult the ABAQUS Answers database in the ABaQUS Online Support System for information about knowninstallation problems. If this does not address your situation, please create an incident in the AOSS anddescribe your problem, including the output from abaqus info=support. If you call, mail, e-mail, or faxus about a problem(instead of using the Aoss), please provide the output from abaqus info=support. Itis important that you provide as much information as possible about your problem: error messages from anaborted analysis, output from the abaqus info=support command, etc
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数字万用表的设计
一个很不错数字万用表设计，内有详细的电路设计及介绍。流电阻或其他电参量的仪表,其功能可以任意组合并以十进制数字显示被测量结果,应用十分广泛,在传统的电工和电子测量中广泛使用的模拟测量仪虽然具有观察着可以自接看出表针偏转了多个格或满刻度的白分之儿等优点,但要对读数加以换算或说明尤其是不可避免的带来人为视差,不同的观察者可得出不同的结果,数字万用表则不同,他可以直接将测量结果用数字显示出来。数字万用表具有10大特点显示清晰直观,读数准确:为了提高观察的清晰度,新型手持式数字万用表(HDMM)已普遍用字高为26mm(约Lin)的大屏幕LCD(液晶显示器)。有些数字万用表还增加∫背光源,以便于夜间观察读数。为∫提高显示亮度,台式数字万用表大多选用LED数码管或数码管(VFD)。新型数字万用表还增加了标识符显示功能,包括测量项目符号(例如AC、DC、hFF、IOΩ2、IO(iIC、MFM),单位符号(例如mV、V、kV、μA、mA、A、g、k2、M2、nS、H、k、MHz、pF、n、、℃、),特殊符号(如低电压指示符号OBAT”、读数倮持符号“HOID¨或“DH、峰值保持符号“ PEAK HOLD或PH、自动量程符号AUIO、10倍乘符号“*10”、峰鸣器符号等)。有些数字万用表还在液晶显示器的小数点下面设置了量程标识符,例如当小数点下边显示200时,就表明所对应的量程为200,依次类推。为解决数字万用表不能反映被测电压的连续变化过程以及变化趋势这一难题,一种“数字模拟条图仪表也以问世。这里讲的模拟条图有双重含义:第一,被测量为连续变化的模拟量:第二,利用条图形来模拟被测量的大小及变化趋势。这类仪表将数字显示与高分辩率模拟条图显示集于一身,兼有数字万用表与指针万用表之优点,为用效字万用表完仝取代指针万用表创造了条件。智能数字万用表带微处理器与标准接口,可配计算机和打印机进行数据处理或自动打印,构成完整的测试系统。显示位数:字万用表的显示位数通常为312位~812位。具体讲,有31/2位、323位、334位、412位、43/4位、51/2位、612位、71/2位、812位供9种。判定数字万用表的位教有内条原则:第一,能显示从09所有数字的位是整数值;第二,分数位的数值是以最大显示值中最高位的数字为分子,用满量程时最高位的薮字作分母。例如某数字万用表的最大显示值为±1999,满量程计数值为200,这表明该仪表有3个整数位,而分数值的分子为1,分母是2,故称之为31/2位,读作三位半,其最高位只能显示0或1。需要指出的是,目前冇些新型能数字万用表的显示位数比较特殊。例如,VC8145型台式智能数字万用表的满量程值为33000,Ms8050型台式智能数字万用表的满量程值为53000,就很难将其归入哪一种显示位数。这中情况下,通常只给出满量程值。312位数字万用表设计准确度高:确度是测量结果中系统误差与随机误差的综合。它表示测量结果与真值的一致程度,也反映了测量误差的大小,真确度愈高,测量误差愈小。测量的绝对误差有以下三种表达式:△U士(a%RDG+b%KS)1-1)AU=士(a%RDG+(1-2)△U=士(a%RDG+b%S+n)式(1-1)中,RDG为读书值(即显示值),FS表示满量程值。拈号中第1项代表AD转换器和功能转换器(例如分压器)的综合误差,第2项是数字化处理所带来的误差。式(1-2)中,n是量化误差反映在末位数字上的变化量。若把n个字的误差折合成满量程的百分数,则变成式(1-1)。因此,上述二式是完全等价的。式(1-3)比较特殊,第三项通常表示由指针万用表,例如312位、412位数字万用表的准确度分别可达±0.3%、±0.05%1.14分辨力高数字万用表在最低电压量程上末位1个字所代表的电压值,称作仪表的分辨力,它反映了仪表灵敏度的高低。分辨力随显示位数的增加而提高。例如312位、412位、81/2位数字万用表的最高分辨力分别为100μV、10μVlnV。数字万用表的分辨力指标亦可用分辨率来袤示。分辨是指所能显示的最小数字(零除外)与最大数字的百分比。例如,31/2位数字万用表的分辨率为1/19990.05%。测试功能强:字万月表不仅可以测量官流电压(DCⅴ)、交流电压(ACV)、直流电流(DCA)、交流电流(ACA、电阻(g)、二极管正向压降(UF)、晶体管共发射极电流放大系数(hF),还能测量电容(C)、电导(G)、温度(T)和频率(f),而且利用峰鸣器挡(BZ)还可检查线路的通断。VC9850A+、VC9808、MS820H型数字万用表增加了电感挡。有的仪表还有信号发生器挡及AC/DC自动转换功能。新型数字万用表大多增加了下述测试功能:读书保持(HOLD)、逻辑( 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 converterarm对于750V挡,若U,=750V(RMS),则R1×10U=0.45U,m337,5mⅤ=75.0mVR,+rtr4.5×10只要改变小数电位置,即可使750V挡直接显示出U值。具体方法是去掉小数点后仍用200mV基本表测量U,并将显示单位取V,这样就把75.0mV变换成750V。223IU转换器数字万用表的直流电流挡(DCA)一殷设置4挡:2nA、20mA、200mA、20A,IU转换器的电路图2-5所示。其中20A挡专用个输入插孔。被测电流经过分流器可转换成电压信号。分流器由R~R组成,总电阻为100g2。其中,R1和R2采用精密金属膜电阻,R3
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