Rotary Switch Controller Failure Detection via Code Transition Analysis
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Solution Overview
Problem
Existing rotary switches lack a compact failure detection mechanism, posing a risk of unintended motor speed changes and potential damage when used in applications like machine tools, as they often require a large parity bit for fault detection.
Innovation Solution
A controller for rotary switches that monitors signal transitions to detect failures without the need for a parity bit, utilizing a microcomputer and software to analyze output codes and determine anomalies, with options for hardware or software-based failure detection units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a parity bit is added to the rotary switch for failure detection, then reliability is improved, but device complexity and size increase
Solution Approach 1:
The failure detection function is extracted from the rotary switch itself and implemented in the microcomputer controller. The microcomputer monitors the output codes and detects failures through software analysis, eliminating the need for additional hardware parity bits in the switch structure.
Solution Approach 2:
The microcomputer acts as an intermediary between the rotary switch and the control system. It receives output codes from the switch, analyzes them for failures, and then sends appropriate commands, thereby providing failure detection without modifying the switch structure.
2Reliability
If a parity bit terminal is added to the rotary switch, then reliability is improved, but the rotary switch size increases
Solution Approach 1:
The failure detection functionality is extracted from the physical switch structure and relocated to the microcomputer's software. This allows the rotary switch to maintain its compact size while still providing failure detection through code monitoring.
3Reliability
If hardware-based failure detection is implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent replaces potential hardware-based failure detection mechanisms with a software-based solution in the microcomputer. The microcomputer uses software to analyze output codes and detect failures, avoiding the need for additional hardware circuits.
4Device complexity
If the rotary switch operates without failure detection, then device complexity is reduced, but harmful factors increase due to unintended motor speed changes
Solution Approach 1:
The microcomputer continuously monitors the output codes from the rotary switch and compares them against expected valid codes. When an invalid code is detected, the system provides feedback to identify the failure, preventing unintended motor speed changes while maintaining simple controller structure.
Data Source
AI summary
A controller of a rotary switch receives, via a contact receiver, signals from a plurality of fixed contacts of a rotary switch that rotates a movable contact to connect the movable contact to any of the fixed contacts, and outputs a command based on the received signals. The controller of the rotary switch monitors a transition of an output code received from the contact receiver, and determines that a failure has occurred in the rotary switch when the transition of the output code does not match a transition pattern of the output code of the case where the rotary switch operates normally.