The Functional Safety Of Elevator Terminal Speed Monitor System Research

The safe running of elevator is vital to ensure the safety of lives and properties of human beings.The 2003 version of GB 7588 Safety rules for the construction and installation of electric lifts specifies that the safety functions of elevator can only be implemented by safety switches and safety circuits.But the new version of GB7588 and the 2018 version of GB/T 35850 Lifts(elevators),escalators and moving walks--Programmable electronic systems in safety related applications--Part 2:Escalators and moving walks PESSRAE)specifies multiple safety functions which can be implemented by the programmable electronics system.Thus,the concept of functional safety is formally introduced into the elevator field.The research of the safety function implemented by the terminal speed monitoring system of elevator(TSMS)is one of the necessary application requirements for the high-speed elevator.In order to improve the utilization rate of building space and reduce the cost of investment,manufacturers of high-speed elevator mostly choose to use reduced stroke buffers for reducing the height of pit and top floor.For this application,GB 7588 requires that the deceleration process of elevator must be monitored by the elevator control system,which is a safety function.The safety function is such a complex logic that the detection methods of safety electrical switches or simple safety circuits used in traditional control system can't implement it.The programmable electronic system is the best method to implement this safety function because it is based on software which can calculate and analyze the complex logic.TSMS is a system based on microcontroller,its safety integrity level is SIL3 which is the highest SIL of elevator safety functionsThe research of functional safety of TSMS is the key content of this topic,and it is one of the most important parts of the development and design of the safety related system.This topic sets the goal by the definition of the safety requirement specification of TSMS.This topic evaluates the hardware safety integrity of the system quantitatively by FMEDA method and evaluates the systematic safety integrity qualitatively by fuzzy decision-making method after the preliminary design of the system is completed,which ensures the design of the system can meet the requirements of SIL3.This topic designs a series of safety validation methods for the system,and verifies the compliance of the goals of the safety requirement specification.The research result of this topic provides key guidance for the design of elevator safety function by using programmable electronic system.It provides a reference for the development of programmable electronic systems which need to meet safety requirements in elevator field or other fields.