Elevator Door Safety Polling Frequency Optimization
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Solution Overview
Problem
Traditional elevator safety systems face inefficiencies in data communication, leading to increased costs and potential safety delays due to serially connected hoistway door contacts and high-performance communication buses required in large systems, making it time-consuming to identify faulty components.
Innovation Solution
Implementing a communication bus system where the control unit polls door safety units within a predetermined distance from the elevator car's position more frequently and those outside this range less frequently or not at all, reducing data traffic while maintaining safety by focusing on critical door safety units near the elevator's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all door safety units are polled frequently to maintain safety, then safety is improved, but communication bus traffic increases significantly
Solution Approach 1:
The patent applies local quality by differentiating the polling frequency based on the spatial relationship between the elevator car and door safety units. Door safety units within a predetermined distance (e.g., 5 floors) are polled frequently to ensure safety, while those farther away are polled less frequently or not at all. This creates a localized high-priority monitoring zone around the elevator car, optimizing the balance between safety and communication load.
2Reliability
If door safety units far from the elevator car are polled frequently, then complete safety monitoring is achieved, but communication costs and system complexity increase
Solution Approach 1:
The patent segments the door safety units into two distinct groups based on their distance from the elevator car: nearby units within a predetermined distance and distant units beyond that distance. This segmentation allows the system to apply different polling strategies to each group, reducing the overall communication burden while maintaining adequate safety monitoring for both zones.
3Device complexity
If serially connected door contacts are used, then system complexity is reduced, but diagnostic capability and fault location ability deteriorate
Solution Approach 1:
The patent implements feedback mechanisms where door safety units transmit their status and diagnostic information to the control unit via the communication bus. This allows the system to maintain relatively simple wiring while gaining enhanced diagnostic capabilities through information feedback from distributed sensors, enabling fault location and system state monitoring.
Data Source
AI summary
An elevator safety system comprises a plurality of door safety units, each door safety unit; a communication bus connecting the plurality of door safety units; a control unit connected to the communication bus for allowing communication between the plurality of door safety units and the control unit; and at least one position sensor configured for providing information about the current position of an elevator car within a hoistway. Each door safety unit is assigned to an elevator hoistway door and configured for monitoring a condition of the assigned elevator hoistway door. The control unit is configured for polling door safety units included in a subset S1, S2) of the door safety units which are located within a predetermined distance (D1, D2) from the current position of the elevator car.