Data Acquisition Device Noise Filtering via Signal Edge Timing
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Solution Overview
Problem
Existing data acquisition methods in control systems suffer from delays due to noise-induced signal fluctuations, leading to erroneous data acquisition and unintended timing issues, particularly when acquiring real-time values from encoders.
Innovation Solution
A data acquisition method that detects the edge of an input signal to trigger data retention and starts a timer for signal stabilization, allowing data to be latched only when the signal remains stable, and prohibits interrupts during this process to prevent noise-induced errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If data acquisition is triggered by interrupt on signal edge, then real-time response is improved, but noise-induced false acquisition increases
Solution Approach 1:
The patent applies preliminary action by acquiring data at the signal edge (interrupt timing) before fully processing and validating it. The data is acquired immediately when the interrupt occurs, then subsequently validated against stability criteria. This separates the fast acquisition trigger from the slower validation process, maintaining real-time responsiveness while filtering out noise-induced false acquisitions through post-acquisition validation.
2Loss of time
If data is acquired immediately upon interrupt, then timing accuracy is improved, but noise influence increases
Solution Approach 1:
The patent implements feedback by continuously monitoring the signal level after acquisition and comparing it against predetermined stability criteria. The acquired data is fed back into the validation process, where it is checked against the current signal state. If the signal has stabilized according to the feedback criteria, the data is confirmed as valid. This feedback mechanism allows immediate acquisition while filtering out noise through subsequent validation based on signal stability.
3Reliability
If signal stabilization is verified before latching data, then noise removal is improved, but processing time increases
Solution Approach 1:
The patent applies preliminary action by performing the data acquisition at the interrupt timing (signal edge) before completing the stabilization verification process. The data is acquired immediately when the interrupt occurs, then the stabilization criteria are applied as a subsequent validation step. This separates the fast acquisition trigger from the slower validation process, maintaining real-time responsiveness while ensuring data validity through post-acquisition stabilization checking.
4Productivity
If interrupt is enabled continuously, then data acquisition responsiveness is improved, but false interrupts from noise increase
Solution Approach 1:
The patent applies preliminary action by maintaining interrupt enablement in its default state to ensure immediate response to valid signal edges. The interrupt mechanism remains active and responsive, but subsequent validation against stability criteria filters out false interrupts caused by noise. This allows continuous monitoring and immediate acquisition while using post-acquisition validation to eliminate spurious interrupts from noise-induced signal fluctuations.
Data Source
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AI summary
A data acquisition method of acquiring and latching data with a timing based on an input signal supplied to an input port, the method including: acquiring and retaining the data with a timing of when an edge of the input signal is detected, and starting a timer; and at the time of expiration of the timer, if the level of the input signal is a first level that is unchanged from start of the timer, latching the retained data and if the level of the input signal is a second level that is changed from the start of the timer, discarding the retained data.