毕业论文外文译文-工业混料过程的自动化解决方案

PAGEPAGE1理工大学学生毕业设计（论文）外文译文学生姓名：学号：专业名称：电气工程及其自动化译文标题（中英文）：工业混料过程的自动化解决方案TheAutomationSolutionofIndustrialBlendingProcess译文出处：SIEMENSSTEP7帮助文档指导教师审阅签名：外文译文正文：1、规划自动化项目的基本过程该章概述了规划可编程控制器(PLC)自动化项目所涉及的基本任务。基于自动化控制一个工业混料过程的实例，逐步引导您完成整个过程。规划自动化项目有多种方法。下图阐述了可用于任何项目的基本步骤。图1-1自动化项目规划的基本步骤2、将过程分成任务和区域自动化过程包含大量单个任务。通过在过程内识别相关任务组，然后将这些组分成更小的任务，用这种方法甚至可以定义最为复杂的过程。下面的工业混料过程实例可用于阐述如何将过程划分为一些功能区域和单个任务：图2-1工业混料过程确定过程区域，定义要控制的过程后，将项目分成相关的组或区域：图2-2工业混料工程区域图由于每组都分成小型任务，因此要求控制部分过程的任务变得不太复杂。在工业混料过程实例中，可以识别4个不同区域(参见表2-1)。在该实例中，配料A区域包含的设备与配料B区域相同。表2-1工业混料工程区域功能区域所使用的设备配料A配料A的进料泵、入口阀、进料阀、流量传感器配料B配料B的进料泵、入口阀、进料阀、流量传感器混料罐搅拌器电机、罐液位测量开关排料排料阀3、描述单个功能区域在过程内描述每个区域和任务时，不仅需要定义每个区域的操作，还需要定义控制该区域的不同元件。这些元件包括：每个任务的电气、机械和逻辑输入和输出单个任务之间的互锁和依赖性工业混料过程实例使用泵、电机和阀。必须精确描述识别操作期间所要求的操作特性和互锁类型。下表提供了描述工业混料过程中所使用设备的实例。完成描述后，也可以使用它来订购需要的设备。表3-1进料泵电机配料A/B:进料泵电机进料泵电机将混料A和B传送到混料罐。流速：每分钟400L(100加仑)；额定值：1200rpm时为100kw(134hp)。通过混料罐附近的操作员站控制泵(启动/停止)。计数器启动次数用于维护。可通过一个按钮将计数器和显示器复位。要操作泵，必须满足下列条件：混料罐不满；闭合混料罐的排料阀；没有激活紧急断电。如果满足下列条件，汞将关闭：启动泵电机7秒后，流量传感器指示无流量；流量传感器指示停止流动。表3-2入口和排料阀配料A/B:入口和排料阀配料A和B的入口阀和进料阀可允许或防止配料流入混料罐中。阀有一个具有弹簧复位的螺线管。激活螺线管时，打开阀；取消激活螺线管时，闭合阀。由用户程序控制入口阀和进料阀。要激活阀，必须满足下列条件：进料泵电机已经运行1秒以上。如果满足下列条件，泵将关闭：流量传感器指示无流量。表3-3搅拌电机搅拌器电机搅拌器电机在混料罐中混合排料A和配料B。额定值：1200rpm时为100kw(134hp)。通过混料罐附近的操作员站控制搅拌器电机(启动/停止)。计数启动次数用于维护。可通过一个按钮将计数和显示器复位。要操作泵，必须满足下列条件：罐液位传感器没有指示“罐液位低于最小值”；混料罐的排料阀闭合；没有激活紧急断电。如果满足下列条件，泵将关闭：流速计在启动电机后10秒内不指示已经到达额定速度表3-4排料阀排料阀排料阀允许将混料物(通常为重力进料)排放到过程的下一个阶段。阀有一个具有弹簧复位的螺线管。激活螺线管时，打开出口阀；取消激活螺线管时，闭合出口阀。通过操作员站控制出口阀(打开/关闭)。可在下列条件下打开排料阀：搅拌器电机关闭；罐液位传感器没有指示“罐空”；没有激活紧急断电。如果满足下列条件，泵将关闭：罐液位传感器指示“罐空”。表3-5罐液位测量开关罐液位测量开关混料罐中的开关指示罐中的液位，用于互锁进料泵和搅拌机电机。4、列出输入、输出和输入/输出写完要控制的每个设备的物理描述后，需绘制每个设备或任务区域的输入和输出图。图4-1设备输入输出图这些图与要编程的逻辑块相一致。4.1创建电机的I/O图在工业混料过程的实例中使用两个进料泵和一个搅拌机。每个电机都由其自身的"电机块"控制，该块对于所有三个设备都相同。该块要求6个输入：两个输入用于启动或停止电机，一个输入用于复位维护显示器，一个输入用于电机响应信号(电机运行/不运行)，一个输入用于时间，在该时间内必须接收响应信号，一个输入用于测量时间的计时器数目。逻辑块还要求四个输出：两个输出指示电机的操作状态，一个输出指示故障，另一个输出用于指示应该开始维护电机。需要输入/输出来激活电机。它用于控制电机，但同时也可在"电机块"的程序中进行编辑和修改。图4-2电机块的I/O图4.2创建阀的I/O图每个阀都由其自身的"阀块"控制，该块对于所使用的所有阀都相同。逻辑块有两个输入：一个输入用于打开阀，一个输入用于关闭阀。它还有两个输出：一个输出用于指示阀打开，另一个输出用于指示阀闭合。阀块有一个输入/输出，用于激活阀。它用于控制阀，但同时也可在"阀块"的程序中进行编辑和修改。图4-3阀块的I/O图5、建立安全要求根据法律要求和人身健康及安全策，确定需要哪些附加元件，以确保过程安全。在描述中，还应该包括安全元件对过程区域的所有影响。5.1定义安全要求查找要求硬件电路满足安全要求的设备类型。通过定义，这些安全电路可独立于可编程控制器进行操作(虽然安全电路通常提供I/O接口，允许与用户程序协调操作)。通常，可以组态矩阵式，在其自身的紧急断电范围内连接每个执行器。该矩阵式是安全电路的电路图基础。按如下执行来设计安全机制：确定单个自动化任务之间的逻辑和机械/电气互锁。设计电路，允许在紧急情况下手动操作属于该过程的设备。为确保操作过程安全，需建立更多安全要求。5.2创建安全电路工业混料过程实例使用下列逻辑电路作为安全电路：紧急断电开关切断下列设备电源，与可编程控制器(PLC)无关：配料A的进料泵；配料B的进料泵；搅拌器电机；阀。紧急断电开关位于操作员站上。控制器的一个输入指示紧急断电开关的状态。6、描述所要求的操作员显示和控件每个过程都要求有一个操作员界面，允许人员进行干预。部分设计规范包括操作员控制台设计。定义操作员控制台在实例所述的工业混料过程中，可由操作员控制台上的按钮启动或停止每个设备。该操作员控制台包括显示操作状态的指示灯(参见图6-1)。控制台还包括显示灯，用于指示经过一定启动次数后要求维护的设备，以及紧急断电开关，通过该开关可立即终止过程。控制台还有一个复位按钮，用于三台电机的维护显示。通过该按钮，可以关闭指示应该维护电机的维护显示灯，并将相应的计数器复位到0。图6-1操作员控制台7、创建组态图将设计要求文档化后，必须决定项目所要求的控制设备类型。通过确定希望使用哪些模块，还可以确定可编程控制器的结构。创建一个确定下列各项的组态图：CPU型号I/O模块的编号和类型组态物理输入和输出下图阐述了用于工业混料过程的S7组态实例。图7-1工业混料过程的S7组态实例外文正文：1、BasicProcedureforPlanninganAutomationProjectThischapteroutlinesthebasictasksinvolvedinplanninganautomationprojectforaprogrammablecontroller(PLC).Basedonanexampleofautomatinganindustrialblendingprocess,youareguidedstepbystepthroughtheprocedure.Therearemanywaysofplanninganautomationproject.Thebasicprocedurethatyoucanuseforanyprojectisillustratedinthefollowingfigure.Figure1-1automationprojectplanningthebasicsteps2、DividingtheProcessintoTasksandAreasAnautomationprocessconsistsofanumberofindividualtasks.Byidentifyinggroupsofrelatedtaskswithinaprocessandthenbreakingthesegroupsdownintosmallertasks,eventhemostcomplexprocesscanbedefined.Thefollowingexampleofanindustrialblendingprocesscanbeusedtoillustratehowtoorganizeaprocessintofunctionalareasandindividualtasks:Figure2-1IndustrialBlendingProcessDeterminingtheAreasofaProcessAfterdefiningtheprocesstobecontrolled,dividetheprojectintorelatedgroupsorareas:Figure2-2mixtureofindustrialengineeringregionalplansAseachgroupisdividedintosmallertasks,thetasksrequiredforcontrollingthatpartoftheprocessbecomelesscomplicated.Inourexampleofanindustrialblendingprocessyoucanidentifyfourdistinctareas(seetablebelow).Inthisexample,theareaforingredientAcontainsthesameequipmentastheareaforingredientB.Table2-1mixtureindustrialscaleregionalprojectsFunctionalAreaEquipmentUsedIngredientAFeedpumpforingredientA;InletvalveforingredientA;FeedvalveforingredientA;FlowsensorforingredientA.IngredientBFeedpumpforingredientB;InletvalveforingredientB;FeedvalveforingredientB;FlowsensorforingredientBMixingtankAgitatormotor;Switchfortanklevelmeasurement.DrainDrainvalve.3、DescribingtheIndividualFunctionalAreasAsyoudescribeeachareaandtaskwithinyourprocess,youdefinenotonlytheoperationofeacharea,butalsothevariouselementsthatcontrolthearea.Theseinclude:Electrical,mechanical,andlogicalinputsandoutputsforeachtaskInterlocksanddependenciesbetweentheindividualtasksThesampleindustrialblendingprocessusespumps,motors,andvalves.Thesemustbedescribedpreciselytoidentifytheoperatingcharacteristicsandtypeofinterlocksrequiredduringoperation.Thefollowingtablesprovideexamplesofthedescriptionoftheequipmentusedinanindustrialblendingprocess.Whenyouhavecompleteddescription,youcouldalsouseittoordertherequiredequipment.Table3-1feedpumpmotorsIngredientsA/B:FeedPumpMotorsThefeedpumpmotorsconveyingredientsAandBtothemixingtank.Flowrata:400I(100gallons)perminute.Rating:100kw(134hp)at1200rpm.Thepumpsarecontrolled(start/stop)fromanoperatorstationlocatednearthemixingtank.Thenumberofstartsiscountedformaintenancepurposes.Boththecountersandthedisplaycanberesetwithonebutton.Thefollowingconditionsmustbesatisfiedforthepumpstooperate:Themixingtankisnotfull;Thedrainvalveofthemixingtankisclosed;Theemergencyoffisnotactivated.Thepumpsareswitchedoffifthefollowingconditionissatisfied:Theflowsensorsignalsnoflow7secondsafterthepumpmotorisstarted.Theflowsensorsignalsthattheflowhasceased.Table3–2InletandFeedValvesIngredientsA/B:InletandFeedValvesTheinletandfeedvalvesforingredientsAandBalloworpreventtheflowoftheingredientsintothemixingtank.Thevalveshaveasolenoidwithaspringreturn.Whenthesolenoidisactivated,thevalveisopened.Whenthesolenoidisdeactivated,thevalveisclosed.Theinletandfeedvalvesarecontrolledbytheuserprogram.Forthevalvestobeactivated,thefollowingconditionmustbesatisfied:Thefeedpumpmotorhasbeenrunningforatleast1second.Thepumpsareswitchedoffifthefollowingconditionissatisfied:Theflowsensorsignalsnoflow.Table3–3AgitatorMotorAgitatorMotorTheagitatormotormixesingredientAwithingredientBinthemixingtank.Rating:100kW(134hp)at1200rpmTheagitatormotoriscontrolled(start/stop)fromanoperatorstationlocatednearthemixingtank.Thenumberofstartsiscountedformaintenancepurposes.Boththecountersandthedisplaycanberesetwithonebutton.Thefollowingconditionsmustbesatisfiedforthepumpstooperate:Thetanklevelsensorisnotsignaling"Tankbelowminimum."Thedrainvalveofthemixingtankisclosed.Theemergencyoffisnotactivated.Thepumpsareswitchedoffifthefollowingconditionissatisfied:Thetachometerdoesnotindicatethattheratedspeedhasbeenreachedwithin10secondsofstartingthemotor.Table3–4DrainValveDrainValveThedrainvalveallowsthemixturetodrain(usinggravityfeed)tothenextstageintheprocess.Thevalvehasasolenoidwithaspringreturn.Ifthesolenoidisactivated,theoutletvalveisopened.Ifthesolenoidisdeactivated,theoutletvalveisclosed.Theoutletvalveiscontrolled(open/close)fromanoperatorstation.Thedrainvalvecanbeopenedunderthefollowingconditions:Theagitatormotorisoff.Thetanklevelsensorisnotsignalingtankempty.Theemergencyoffisnotactivated.Thepumpsareswitchedoffifthefollowingconditionissatisfied:Thetanklevelsensorisindicating"Tankempty."Table3–5SwitchesforTankLevelMeasurementSwitchesforTankLevelMeasurementTheswitchesinthemixingtankindicatethelevelinthetankandareusedtointerlockthefeedpumpsandtheagitatormotor.4、ListingInputs,Outputs,andIn/OutsAfterwritingaphysicaldescriptionofeachdevicetobecontrolled,drawdiagramsoftheinputsandoutputsforeachdeviceortaskarea.Figure4-1equipmentinputandoutputplansThesediagramscorrespondtothelogicblockstobeprogrammed.4.1CreatinganI/ODiagramfortheMotorsTwofeedpumpsandoneagitatorareusedinourexampleofanindustrialblendingprocess.Eachmotoriscontrolledbyitsown"motorblock"thatisthesameforallthreedevices.Thisblockrequiressixinputs:twotostartorstopthemotor,onetoresetthemaintenancedisplay,oneforthemotorresponsesignal(motorrunning/notrunning),oneforthetimeduringwhichtheresponsesignalmustbereceived,andoneforthenumberofthetimerusedtomeasurethetime.Thelogicblockalsorequiresfouroutputs:twotoindicatetheoperatingstateofthemotor,onetoindicatefaults,andonetoindicatethatthemotorisdueformaintenance.Anin/outisalsonecessarytoactivatethemotor.Itisusedtocontrolthemotorbutatthesametimeisalsoeditedandmodifiedintheprogramforthe"motorblock.".Figure4-2motorblockI/Omap4.2CreatinganI/ODiagramfortheValvesEachvalveiscontrolledbyitsown"valveblock"thatisthesameforallvalvesused.Thelogicblockhastwoinputs:onetoopenthevalveandonetoclosethevalve.Italsohastwooutputs:onetoindicatethatthevalveisopenandtheothertoindicatethatitisclosed.Theblockhasanin/outtoactivatethevalve.Itisusedtocontrolthevalvebutatthesametimeisalsoeditedandmodifiedintheprogramforthe"valveblock."Figure4-3valveblockI/Omap5、EstablishingtheSafetyRequirementsDecidewhichadditionalelementsareneededtoensurethesafetyoftheprocess-basedonlegalrequirementsandcorporatehealthandsafetypolicy.Inyourdescription,youshouldalsoincludeanyinfluencesthatthesafetyelementshaveonyourprocessareas.5.1DefiningSafetyRequirementsFindoutwhichdevicesrequirehardwiredcircuitstomeetsafetyrequirements.Bydefinition,thesesafetycircuitsoperateindependentlyoftheprogrammablecontroller(althoughthesafetycircuitgenerallyprovidesanI/Ointerfacetoallowcoordinationwiththeuserprogram).Normally,youconfigureamatrixtoconnecteveryactuatorwithitsownemergencyoffrange.Thismatrixisthebasisforthecircuitdiagramsofthesafetycircuits.Todesignsafetymechanisms,proceedasfollows:Determinethelogicalandmechanical/electricalinterlocksbetweentheindividualautomationtasks.Designcircuitstoallowthedevicesbelongingtotheprocesstobeoperatedmanuallyinanemergency.Establishanyfurthersafetyrequirementsforsafeoperationoftheprocess.5.2CreatingaSafetyCircuitThesampleindustrialblendingprocessusesthefollowinglogicforitssafetycircuit:Oneemergencyoffswitchshutsdownthefollowingdevicesindependentoftheprogrammablecontroller(PLC):FeedpumpforingredientA;FeedpumpforingredientB;Agitatormotor;Valves.Theemergencyoffswitchislocatedontheoperatorstation.Aninputtothecontrollerindicatesthestateoftheemergencyoffswitch6、DescribingtheRequiredOperatorDisplaysandControlsEveryprocessrequiresanoperatorinterfacethatallowshumaninterventionintheprocess.Partofthedesignspecificationincludesthede