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The Design Of Escalators Functional Safety System

Posted on:2014-01-19Degree:MasterType:Thesis
Country:ChinaCandidate:Q ZhangFull Text:PDF
GTID:2232330398964767Subject:Electronic and communication engineering
Abstract/Summary:PDF Full Text Request
In modern society with developed technology, escalators and moving walks are publicessential transportation at station,shopping malls and subway stations.They can not onlygreatly ease the busy traffic pressure,but also bring great convenience for the society.Butwith the increasing number of escalators and the rapid development of the technology,theescalator accidents are on the rise in recent years.Escalator accidents not only caused hugeeconomic losses, but also for the victim’s personal safety damage is very serious.In order tostrengthen the safety performance of escalators,our country introduced a new standardGB16899-2011("Safety Criterion of Escalators and Moving Walks’ manufacture andinstallation") as the basic guarantee of escalators and moving walks’ safetyoperation.Programmable electronic system in safty should be tested by specializedagencies with type test.Therefore,designing one escalators functional safety system withlower cost and higher performance in accordance with the new standard is of greatpractical significance.The paper introduced the design of escalators functional safety system, systemincludes sensor subsystem, logic subsystem and the final element subsystem.The corefunctional safety control board uses dual redundant pattern of signal sampling via doublechannels,logic judgment via double channels and output via double channels,in orderto improve the reliability of the system.Logic judgment uses LPC2368controller unitbased on ARM7kernel,it controls the safety relays linked in safe circuit and additionalbrake circuit according to the judgment of signal from the escalator.Though the escalatorviolates the security function,safety function system will enable the escalator into thefailure mode.Some failure mode can’t return to the normal operation mode without externalmanual reset.Each safety function hardware of this system uses the failure mode effectdiagnosis and analysis (FMEDA).Through quantitative analysis of safety integritylevel(SIL),system reached the standard of SIL2.Software is designed according to thesystem safety requirements. At last,escalator functional safety system succeeds in passing the type test by Shanghai Jiao Tong University elevator testing center.
Keywords/Search Tags:escalator, functional safety, FMEDA, ARM, safety integrity level
PDF Full Text Request
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