Landing Door Switch Group Detection for Faster Elevator Fault Isolation
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Solution Overview
Problem
Elevator systems face delays and passenger safety risks due to the failure of a single landing door switch causing a broken safety chain, leading to prolonged entrapment and difficulty in locating the faulty switch.
Innovation Solution
A method and device for detecting the states of multiple landing door switches by organizing them into switch groups, using signal input and output lines connected to a controller that applies detection signals sequentially to determine the state of each switch, enhancing reliability with pulse signals and SPI interfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If landing door switches are connected in series to form a safety chain, then the elevator system can detect door states, but a single switch failure causes the entire safety chain to break and stops the elevator
Solution Approach 1:
The patent divides the landing door switches into multiple independent groups (first group, second group, etc.), where each group can be independently detected and controlled. This segmentation allows the elevator system to identify which specific group or switch has failed without the entire system shutting down, thereby maintaining operational continuity while preserving detection reliability.
2Device complexity
If traditional series connection is used for landing door switches, then the system structure is simple, but locating a faulty switch takes a long time and causes prolonged passenger entrapment
Solution Approach 1:
By organizing switches into distinct groups with separate detection circuits, the patent enables targeted fault isolation. When a fault occurs, the system can quickly identify which specific group is affected, dramatically reducing the time required to locate and troubleshoot the faulty switch compared to checking each switch individually in a series connection.
Solution Approach 2:
The patent implements independent detection circuits for each switch group that provide feedback signals to the control device. This feedback mechanism allows the system to automatically identify which group has failed, enabling rapid fault location and reducing passenger entrapment time without requiring manual inspection of each switch.
3Measurement precision
If all landing door switches are monitored individually, then fault location is accurate, but the system complexity and detection time increase
Solution Approach 1:
The patent achieves accurate fault location by dividing switches into groups, where each group is monitored by its own detection circuit. This approach provides precise identification of the faulty group while keeping the detection system complexity manageable through modular design, avoiding the need for overly complex individual switch monitoring.
Solution Approach 2:
The patent combines multiple switches within each group to share a common detection circuit, reducing the overall number of detection circuits needed. This merging approach maintains accurate fault location capability at the group level while simplifying the detection system compared to fully individual switch monitoring.
Data Source
AI summary
A method and device for detecting states of a plurality of landing door switches, an elevator system. The plurality of landing door switches are divided into m switch groups. The device for detecting the states of the plurality of landing door switches includes m signal input lines and n signal output lines. Each signal input line is connected with a first end or input end of each landing door switch within one of the m switch groups, and each signal output line is connected with a second end or output end of one of the landing door switches within each of the m switch groups. A controller is connected with the m signal input lines and the n signal output lines, and is configured to apply a detection signal onto the ith signal input line and determine the state of each landing door switch.