Double Throw Switch Bouncing Reduction via Parallel Logic Circuits
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Solution Overview
Problem
Multiple-contact switches in process control systems experience mechanical and electrical bouncing, leading to poor accuracy and rapid wear, which existing solutions often address at the cost of reduced responsiveness.
Innovation Solution
The implementation of double throw switches with common contacts and throw circuits that use logic gates and pull-up resistors to maintain signal states during bouncing, ensuring accurate output without time-delay circuits that reduce responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time-delay circuits are used to reduce sensitivity to bouncing, then measurement precision improves, but responsiveness deteriorates
Solution Approach 1:
The patent divides the switch contacts into multiple independent circuits (first contact circuit, second contact circuit, third contact circuit) that operate in parallel. Each circuit independently detects the switch state, and the final output is determined by the collective state of all circuits. This segmentation allows the system to ignore transient bouncing in individual circuits while maintaining rapid response through the parallel architecture, resolving the contradiction between measurement precision and responsiveness.
Solution Approach 2:
The patent introduces an intermediary logic layer that processes signals from multiple contact circuits before producing the final output. Instead of directly responding to individual contact states, the system uses an intermediate evaluation stage that considers the overall state of all contact circuits. This intermediary layer filters out bouncing effects while preserving rapid response capability, as the intermediate logic can quickly determine the stable state without requiring time-delay circuits.
2Device complexity
If mechanical switches are used to control process variables, then device complexity is reduced, but reliability deteriorates due to bouncing and wear
Solution Approach 1:
The patent merges multiple contact circuits into a single unified switch device with a common actuator. Instead of using multiple separate switches, the invention combines several contact circuits that are all controlled by the same mechanical actuator. This merging maintains the simplicity of a single mechanical device while improving reliability through the redundant parallel circuits that collectively determine the output state, reducing the impact of bouncing and wear on any individual contact.
Data Source
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AI summary
Multiple-contact switches are disclosed. An example multiple-contact switch disclosed herein includes a double throw switch having a common terminal, a first throw terminal, and a second throw terminal, the common terminal being coupled to a reference; a first throw circuit coupled to the first throw terminal, the first throw circuit to output an open signal to a process control device when the common terminal is substantially in contact with one of the first throw terminal or the second throw terminal; and a second throw circuit coupled to the second throw terminal, the second throw circuit to cause the first throw circuit to output a close signal to the process control device when the common terminal is substantially in contact with the other one of the first throw terminal or the second throw contact terminal, wherein at least one of the open signal or the close signal corresponds to the reference.