发布网友 发布时间:2024-10-23 06:17
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热心网友 时间:2024-11-06 05:46
Hgh reliability is the key to the electrical control equipment performance.PLC as a result of the modern large scale integrated circuit technology, the strict production craft manufacture, the internal circuit adopted advanced anti-interference technology, has the very high reliability.热心网友 时间:2024-11-06 05:47
High reliabilityis the keyperformanceof electrical control equipment.PLC due to the use of modernlarge scale integrated circuit technology,used the strict production craft manufacture,the internal circuit has adopted the advancedanti-jamming technology,with high reliability.For example,the Fseries PLCproduced by Mitsubishi Co,the mean time to failureof up to 300000hours.Some use theredundant CPUPLCmean time to failureis longer.From theexternalcircuit of PLC,the use of PLCcontrol system,compared with thesamescale relay system,the electrical wiring and the switch contacthas been reduced tohundreds or even thousandsof,the faultisgreatly reduced.In addition,self -detection functionwithPLC hardware failures,failure to issue timely warninginformation.In the application software,userscan alsofault self diagnosisprogramof peripheral devices,thesystemcircuitand equipmentexcept PLCaccess to the protection fault self-diagnosis.In this way,the reliability of the wholesystem with highis also not surprising.This paper focuses onthecontrol ofcrane,thecontrolmethod usingseries resistancehave been implementedto control the motor,so as to control thecrane.The working mode of PLCPLC sourceforcomputer controlinstead ofrelay contactor,so PLChassimilaritieswiththe general-purpose computer,such as with the samebasic structure andprinciple ofthe sameinstruction execution.However,the twoways of workinghaveimportant differences,the differences reflectthecircularscanning modein PLCCPU,focus on theinput sampling,focus on theoutputrefresh,I/Oimage areaseparately.Resultstheinput stateand process ofexecuting the programin the previousstate.The process ofcircularscanning modescanningmode of PLCPLCworkpackage,generallyfive stages,internal processingand self diagnosis,peripheralcommunicationprocessing,the input sample,the user program execution,the outputrefresh.