Multiplexer Switching Device for Helicopter Side Stick Wire Reduction
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Solution Overview
Problem
Existing switching devices for helicopters, such as side sticks, require numerous wires due to the use of either normally closed (NC) or normally open (NO) contacts in multiplexing switch data, limiting the reduction of wire count in current architectures.
Innovation Solution
A multiplexer switching device combining a data network with both NC and NO contacts connected via a common DC voltage link, with each contact type paired with a resistor, allowing for reduced wire usage by multiplexing information through fewer signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiplexing is implemented using traditional in-line or matrix-type data networks with single contact type (NC or NO), then the number of wires is reduced, but the wire count reduction is limited and cannot achieve optimal minimization
Solution Approach 1:
The patent merges NC and NO contact types into a single multiplexed data network, allowing both contact types to share common signal lines. This combining approach enables further wire reduction compared to traditional separate NC or NO networks, as the same physical wires carry multiplexed signals from multiple switch contacts of different types.
Solution Approach 2:
The common DC voltage link serves multiple functions: it provides power to the switch contacts, acts as a signal return path, and enables bidirectional communication. This multi-functionality reduces the need for dedicated power and signal wires, achieving optimal wire count minimization while maintaining system capability.
2Quantity of substance
If a common DC voltage link is used to connect NO and NC contacts, then wire count is minimized, but electrical interference or signal conflicts may occur between the two contact types
Solution Approach 1:
The patent introduces resistors as intermediary elements in the data networks connected to the common DC voltage link. These resistors act as mediators that isolate electrical conflicts between NC and NO contacts while allowing signal transmission, thereby preventing direct electrical interference on the shared wires.
Solution Approach 2:
The patent uses resistors to change the electrical parameters (impedance, voltage division) of the data networks. By carefully selecting resistor values, the system adapts the electrical characteristics to prevent signal conflicts while maintaining reliable communication, resolving the reliability concern of using a common voltage link.
3Reliability
If resistors are added to each contact in the multiplexed network, then signal conflicts are prevented, but the device complexity and component count increase
Solution Approach 1:
The resistors serve multiple functions: they prevent electrical conflicts between NC and NO contacts, enable proper voltage division for logic level detection, and provide current limiting protection. This multi-functionality justifies the added components by achieving reliable signal transmission without requiring additional complex protection circuits.
Solution Approach 2:
The resistors are used to adjust electrical parameters (impedance matching, voltage division ratios) to optimal values that prevent signal conflicts. By selecting appropriate resistor values, the system achieves reliable operation with simple passive components rather than complex active protection circuits.
Data Source
AI summary
A multiplexer switching device is described herein comprising a first data network comprising a plurality of NO contacts; and a second data network comprising a plurality of NC contacts; wherein said a first data network is connected to said second data network via a common DC voltage link.