鞍山科技大学本科生毕业设计（论文）第PAGEIV页PLC与变频器结合实现电动机恒转矩控制摘要本文介绍了一种由西门子PLC和变频器构成的恒转矩控制系统.采用PROFIBUS协议实现了PLC与变频器的通讯.介绍PROFIBUS通信协议,以德国西门子公司MICROMASTER440型变频器为例,介绍了PLC与变频器进行通信的硬件连接。依据该协议,实现了以PLC作为控制器,在PLC环境下编制程序对变频器进行远程控制.该系统可以对各变频器的运行参数进行在线监测,并进行远程控制。文中介绍了关于钢板的清洗工艺,以系统的实际应用来说明本系统的实际价值，调节刷辊的转矩来控制对钢板的刷洗力度。最后附以程序,有PLC和变频器的通讯的程序和PLC与变频器结合控制电动机恒转矩的PLC程序.实践证明,该系统能有效地减少系统布线、提高系统的抗干扰能力,为恒转矩控制系统提供了一个低成本和高性能的方案。关键词：PLC，变频器，PROFIBUS协议PLCCombiningWithFrequency-converterAchievingConstantTorqueControlOfElectricMotorAbstractThispaperintroducesacontrolsystemforinstancetorquecomposedofSIEMENSPLCandfrequency-converter.TheserialcommunicationbetweenPLCandfrequency-converterisrealizedbasedonthePROFIBUSprotocol.ThePROFIBUSprotocolisintroducedindetail.HardwarelinkofcommunicationbetweenPLCandfrequency-converterareintroducedwithanexampleofSIEMENSfrequency-converterMICROMASTER440.Accordingtothisprotocol,remotecontrolofinverterisrealizedwithSIEMENSPLCbeingcontrollerundertheenvironmentofvisualPLC.Thepresentedsystemisveryconvenienttomonitortheparametersofeveryfrequency-converteronlineandrealizethedistancecontrol.Thepaperintroducedsteelcleaningprocessesforthesystemtoillustratethepracticalapplicationoftheactualvalueofthesystem,Adjustingbrushrollertorquetocontrolbrushrollerintensityontheskinofsteel.Atlast,togetherwithprocedures,therearecommunicationproceduresofPLCandfrequency-converterandtheproceduresofPLCcombiningwithfrequency-converterachievingconstanttorquecontrolofelectricmotor.Practicehasprovedthatthemethodcanreduceelectricconnectionsandimprovetheanti-jammingcapabilityofthesystem.TherebyaschemeforPLCcombiningwithfrequency-convertertoachieveconstanttorquecontrolofelectricmotorwithlow-costandhigh-performanceisprovided.Keyword:PLC，frequency-converter，PROFIBUSprotocol目录TOC\o"1-3"\h\zHYPERLINK\l"_Toc143082029"摘要PAGEREF_Toc143082029\hIHYPERLINK\l"_Toc143082032"AbstractPAGEREF_Toc143082032\hIIHYPERLINK\l"_Toc143082033"1绪论PAGEREF_Toc143082033\h1HYPERLINK\l"_Toc14308203