Bus Subscriber Position Detection via Signal Echo
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Solution Overview
Problem
Existing methods for addressing bus subscribers on a parallel bus require a separate token line for initialization, leading to excessive wiring, weight, and connector needs, while only determining sequence, not physical position, and are inefficient in space-constrained environments like aircraft.
Innovation Solution
Implementing a functional parallelization of the bus system where subscribers register IDs randomly and measure distance using signal echoes, eliminating the need for a token line and allowing spatially selective control without additional wiring, using a voltage jump and differential signal to determine position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a separate token line is used for initialization, then bus subscribers can be addressed in sequence, but wiring complexity and weight increase significantly
Solution Approach 1:
The patent merges the initialization function into the existing two-wire bus by using signal reflections off intentionally created discontinuities (such as temporarily opening a relay contact or inserting a high-value resistor) to encode position information, eliminating the need for a separate token line while maintaining the ability to initialize subscribers in sequence
Solution Approach 2:
The patent extracts the position encoding function from a separate physical line and implements it through signal reflection characteristics on the existing bus, using temporary discontinuities to create echo signals that carry position information without requiring additional wiring
2Ease of operation
If a separate token line is laid parallel to the bus, then initialization is possible, but space requirements increase
Solution Approach 1:
The patent combines the initialization and position detection functions into the existing two-wire bus infrastructure by utilizing signal reflections, thereby eliminating the need for separate connectors and space for a parallel token line
3Weight of stationary object
If signal reflections are used to determine position, then separate token line is eliminated, but bus loading increases
Solution Approach 1:
The patent uses periodic initialization sequences where discontinuities are temporarily created only when needed for position detection, allowing the bus to return to its normal low-loading state between initialization cycles, thus managing peak loading while maintaining weight savings
Solution Approach 2:
The patent employs dynamic, temporary discontinuities (such as momentarily opening relay contacts or inserting high-value resistors only during initialization) rather than permanent modifications, allowing the bus impedance to return to its normal state and reducing sustained loading
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
This approach reduces wiring and connector requirements, enabling accurate spatial mapping and control of bus subscribers with reduced circuitry complexity and weight, while allowing for efficient spatial control measures without a separate token line.
Implementation Method 1
The master then feeds a signal into the bus, which signal is reflected at this discontinuity in the subscriber. The delay from the transmitting time to the reception of the signal echo is measured and represents a distance measure of the spatial position of the subscriber along the course (which is known by design) of the bus.
Data Source
AI summary
In order to register the order of bus subscribers (12) when starting a system without the use of a token line to be specifically laid for his purpose along the two-wire bus (11), the bus master (13) temporarily activates a reflective discontinuity, preferably a bus short circuit, in a respective selectively addressed one of the subscribers (12) after stochastically determining all subscriber addresses (Ki). The echo signal (19) of a voltage jump (18), which is then output onto the bus (11) by the master (13), is superimposed in the master (13) to form a square-wave-like differential signal (20) whose pulse duration which is proportional to the distance between the master (13) and that subscriber (12) along the bus (11) is measured following pulse shaping by analog pulse area integration (25).