Multiplexed Self-Diagnostic Circuit for Daisy-Chained Switches
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Circuits with daisy-chained switches in safety-related applications, such as elevator systems, face difficulties in diagnosis due to increased wiring and complications, and regulatory constraints prevent parallel wiring of self-diagnostic subsystems.
Innovation Solution
A self-diagnostic circuit with multiplexed electrical conductors, switches, and microprocessors that use receptor and emitter antennas to generate and receive signals indicative of switch positions, allowing for redundant information and efficient diagnosis without additional wiring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing self-diagnostics for daisy-chained switches are implemented, then diagnostic capability is improved, but wiring complexity and cost increase
Solution Approach 1:
The patent combines the diagnostic function with the existing series circuit by integrating modules that monitor switch states directly into the daisy-chained configuration. The modules use the existing conductor to both power the circuit and transmit diagnostic signals, merging two functions into a single integrated system rather than adding separate diagnostic wiring.
Solution Approach 2:
The electrical conductor serves multiple functions: it provides power to the switches and modules while simultaneously serving as a communication medium for diagnostic signals. The modules themselves perform both circuit control and self-diagnostic functions, eliminating the need for dedicated diagnostic wiring and reducing overall system complexity.
2Measurement precision
If self-diagnostic subsystems are wired in parallel to the circuit being diagnosed, then diagnostic accuracy is improved, but regulatory compliance deteriorates
Solution Approach 1:
The patent merges the diagnostic subsystem with the main circuit by wiring modules in series along the existing conductor rather than creating separate parallel diagnostic paths. This integration allows accurate monitoring of switch states while maintaining compliance with regulations that prohibit parallel wiring of safety-related systems.
Solution Approach 2:
The modules act as intermediaries that monitor switch states by detecting electrical characteristics (such as voltage drops or current changes) through the series conductor. This intermediary approach enables accurate diagnostic information to be obtained without directly wiring diagnostic equipment in parallel, which would violate regulatory requirements.
3Loss of information
If modules monitor switch positions in a daisy chain configuration, then diagnostic information is improved, but signal interference increases
Solution Approach 1:
The patent segments the diagnostic function into individual modules, each responsible for monitoring a specific switch or section of the circuit. Each module processes and transmits information independently, reducing the likelihood that interference in one segment will affect the entire diagnostic system. This modular approach isolates potential sources of interference.
Solution Approach 2:
The modules incorporate feedback mechanisms that allow them to detect and compensate for signal interference. By continuously monitoring signal quality and adjusting transmission parameters or requesting retransmission when interference is detected, the system maintains accurate diagnostic information despite the presence of electromagnetic interference in the daisy-chain configuration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient and redundant switch position monitoring, reducing diagnostic complexity and compliance with regulatory requirements by using a daisy chain configuration that provides redundant information for switch positions, enhancing safety and reliability in programmable electronic systems.
Implementation Method 1
receive a first induced frequency signal from the receptor antenna when the first switch is closed
Data Source
AI summary
A self-diagnostic circuit includes an electrical conductor configured to multiplex, a first switch interposing the electrical conductor, and a first module crossing the first switch. The first module includes a first receptor antenna associated with the conductor on one side of the first switch, a first emitter antenna associated with the conductor on an opposite side of the first switch, and a first interfacing microprocessor. The first interfacing microprocessor is configured to receive no signal from the first receptor antenna when the first switch is open thus generating a first open signal and a first address signal indicative of the first module and outputting the first open signal and the first address signal to the conductor via the first emitter antenna. The first interfacing microprocessor is further configured to receive a first induced frequency signal from the first receptor antenna when the first switch is closed thus generating a first closed signal and the first address signal indicative of the first module and outputting the first closed signal and the first address signal to the conductor via the first emitter antenna.