Automatic Pedestrian Ladder Function Safety System

               Advanced technology in modern society, escalators are the station, shopping malls, subways and other public places in the indispensable means of transport, it is not only very likely to ease the heavy traffic pressure, but also to bring great convenience to society. However, with the increasing number of escalators and the rapid development of technology, there has been a rising trend of escalator accidents in recent years. The frequent occurrence of escalator accidents has not only caused great economic loss, but also seriously harmed the personal safety of the parties. In order to enhance the safety performance of escalators, the state issued a new standard gb16899-2011 "(escalator and sidewalk manufacturing and installation Safety Code") as a basic guarantee for the safe operation of escalators and automatic sidewalks, in which it is proposed that programmable electronic security related systems need to be tested through specialized agencies.Automatic pedestrian ladder

               Therefore, it is of great practical significance to develop an economical and high-performance escalator functional safety System according to the new standard. This paper introduces the research and development of escalator function safety system, including sensor subsystem, logic subsystem and final component subsystem. The core function safety Control Board adopts dual-channel signal sampling, dual-channel logic judgment and dual-channel output dual redundancy mode, which improves the reliability of the system.Automatic pedestrian ladder

               The Logic judgment unit uses the LPC2368 controller of the ARM7 kernel to judge its safety according to the sensor signal of the escalator. Control access safety loop and additional brakes of the safety relays, so that even if there is a breach of safety features of the escalator, the functional safety system will also guide the escalator into a safe mode of failure, and some fault modes must be manually reset outside before entering the normal mode of operation. The hardware of the system realizes each security function through the failure mode, the influence and the Diagnosis Analysis (Fmeda), through the security Integrity quantitative analysis achieves the standard SIL2 grade. The software is designed according to the SIL2 software safety requirements.Automatic pedestrian ladder