燕大机电一体化作业1

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1、Name:何丽080101010069No.:01DueTime:2011.09.04Affiliation:08级机电2班1.4Theautomaticcontrolsystemforthetemperatureofabathofliquidconsistsofareferencevoltagefedintoadifferentialamplifier.Thisisconnectedtoarelaywhichthenswitchesonorofftheelectricalpowertoaheaterintheliqu

2、id.Negativefeedbackisprovidedbyameasurementsystemwhichfeedsavoltageintothedifferentialamplifier.Sketchablockdiagramofthesystemandexplainhowtheerrorsignalisproduced.Answer:comparisonelementamplifierrelayswitchheater+temperatureerrorsignalprocesscontrolunitcorrect

3、ionunitreferencevoltage_measuredvoltagemeasurementsystemThecomparisonelementcomparesthereferencevalueofthevariableconditionbeingcontrolledwiththemeasuredvaluewhichisproducedbythemeasurementsystem,thenitproducesanerrorsignalwhichcanberegardedasaddingthereferences

4、ignal.Accordingtotheformula:Errorsignal=referencevaluesignal−measuredvaluesignalInthiscase:Errorsignal=referencevoltage−measuredvoltage1.8Explainwhatlogicgatesmightbeusedtocontrolthefollowingsituation:(a)Theissueofticketsatanautomaticticketmachineatrailwaystatio

5、n.(b)Asafetylocksystemfortheoperationofamachinetool.Answer:(a)ticketselectedANDcorrectmoneyin,correctmoneydecidedbyORgatesanalysisamongpossibilities.(b)ANDwithsafetyguards,lubricant,coolant,workplace,power,etc.alloperatingorinplace.2.4Whatisthenon-linearityerror

6、,asapercentageoffullrange,producedwhena1KWpotentiometerhasaloadof10KWandisatone-thirdofitsmaximumdisplacement?Answer:Accordingtotheformula:Hence:2.5Whatwillbethechangeinresistanceofanelectricalresistancestraingaugewithagaugefactorof2.1andresistance50Ωifitissubje

7、cttoastrainof0.001?Answer:Accordingtotheformula:Hence:2.8Arotaryvariabledifferentialtransformerhasaspecificationwhichincludesthefollowinginformation:Ranges:±30°,linearityerror±0.5%fullrange±60°,linearityerror±2.0%fullrangeSensitivity:1.1(mV/Vinput)degreeImpedanc

8、e:Primary750Ω,Secondary2000ΩWhatwillbe(a)theerrorinareadingof40°duetonon-linearitywhentheRDVTisusedonthe±60°range,and(b)theoutputvoltagechangethatoccursperdegreeifthe