Electronic Test Nodes for Automated Safety Chain Checks
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Solution Overview
Problem
The existing safety systems in passenger conveyor systems require manual intervention for testing, which is time-consuming and relies on human interaction for a 100% check, making it inefficient and prone to errors.
Innovation Solution
An electronic test node with a processor and a test switch is introduced, allowing for automated and remote testing of safety switches by simulating the opening of the safety switch to detect faults, and communicating test results through a communication bus, reducing the need for manual activation and enabling independent operation from the safety switch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If manual intervention is used to activate safety devices for testing, then the testing can be performed with simple equipment, but the testing process becomes time-consuming and cannot achieve 100% automated check
Solution Approach 1:
The electronic test node enables the safety chain system to test itself automatically. The processor at each node monitors signals from associated safety switches and can independently determine their status without requiring manual activation by service personnel. This self-testing capability achieves full automation and eliminates time loss associated with manual intervention.
Solution Approach 2:
The system continuously monitors safety switch status in real-time through the electronic test nodes, rather than waiting for manual testing. This continuous preliminary monitoring ensures that safety conditions are constantly verified, enabling immediate detection of faults without requiring scheduled manual intervention.
2Reliability
If service personnel physically access multiple safety devices at different locations for testing, then comprehensive testing can be performed, but the process becomes complex and requires human interaction
Solution Approach 1:
The safety chain is divided into multiple electronic test nodes, each responsible for monitoring a specific safety switch or section. Each node contains a processor that independently monitors its associated safety switch, allowing comprehensive coverage of all safety devices while simplifying the overall testing operation to a single automated process.
Solution Approach 2:
Electronic test nodes serve as intermediaries between the safety switches and the central control system. Each test node processor acts as a mediator that continuously monitors safety switch status and communicates with the control unit via the bus, eliminating the need for service personnel to physically access and manually test each safety device.
3Ease of manufacture
If safety switches are integrated with test functions, then testing can be performed, but the device complexity increases and retrofitting becomes difficult
Solution Approach 1:
The test function is extracted from the safety switch itself and implemented as a separate electronic test node. The safety switch remains a simple, standalone component while the electronic test node contains the processor and monitoring logic. This separation maintains simplicity of the safety switch for easy manufacturing and retrofitting, while adding intelligence elsewhere in the system.
Solution Approach 2:
The electronic test node is designed as a universal component that can monitor any safety switch in the chain. The processor in each test node can handle multiple functions including signal monitoring, fault detection, and communication with the control unit. This multi-functionality is achieved in a standardized node design that can be uniformly applied throughout the safety chain.
Data Source
Figure 1a~1b
Figure 2
Figure 3~4
AI summary
An electronic test node (1) for a safety chain (22) in a passenger conveyor system comprises an electrical connection (2) for an associated safety switch (4). A processor (6) is configured to monitor a signal carried by the electrical connection (2) so as to detect whether the associated safety switch (4) is open or closed. The electronic test node (1) further comprises a test switch (8) connected in series with the electrical connection (2), wherein the processor (6) is configured to run a test by selectively opening the test switch (8) and monitoring for a change in the signal carried by the electrical connection (2).