In-Situ Sensor Calibration Using Cyclical Reference Values
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Solution Overview
Problem
Existing inline calibration methods for sensors in processes like water management and laboratory applications often result in incorrect adjustments due to unaccounted ambient influences, leading to inaccurate measured values when reference values are determined outside the process environment.
Innovation Solution
A method and system for calibrating sensors during ongoing operation by analyzing cyclical analyte concentrations in a process vessel, using a conversion function to adjust raw measured values to accurate analyte concentrations, and correcting the calibration function based on selected reference values, allowing for fully or semi-automated calibration without process interruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If reference values are determined in the laboratory using alternative measurement methods, then calibration can be performed outside the process environment, but ambient influences that the sensor is exposed to in the process cannot be taken into account leading to incorrect reference values
Solution Approach 1:
The patent extracts the reference value determination from the laboratory environment and performs it directly within the process environment using the sensor itself. By taking out the need for external laboratory measurement and performing calibration in-situ, the reference values are determined under the actual ambient conditions the sensor experiences during operation, eliminating the discrepancy between calibration and operational environments.
2Productivity
If inline calibration is performed by sampling the measurement medium at a current point in time, then process interruptions are avoided, but the calibration may be incorrect if the reference value is incorrect and this goes unnoticed by the user
Solution Approach 1:
The patent implements feedback by continuously monitoring the sensor output signal over time and comparing it against expected patterns or reference measurements taken at different time points. The system provides feedback to verify whether the calibration adjustment is correct by checking if the calibrated values match independent reference measurements, allowing detection and correction of calibration errors while maintaining process continuity.
Solution Approach 2:
The patent performs preliminary verification of reference values by comparing multiple measurements taken at different time points before finalizing the calibration adjustment. This preliminary action ensures that the reference value is accurate and representative of the actual process conditions, preventing incorrect calibration while avoiding process interruptions.
3Measurement precision
If the sensor is calibrated at regular intervals to guarantee quality of measured values, then measurement accuracy is maintained, but the calibration should not interrupt ongoing operation of the sensor
Solution Approach 1:
The patent enables continuous calibration by performing reference measurements and calibration adjustments directly within the process environment without removing the sensor or interrupting the process flow. The calibration action continues uninterrupted alongside the measurement function, allowing the sensor to maintain accuracy while the process operates continuously. Multiple measurements are taken at different time points to ensure calibration quality without stopping production.
Data Source
AI summary
A method for calibrating a sensor during operation includes determining several raw measured values to determine several analyte concentrations of the medium, saving the raw measured values in the sensor memory, analyzing the stored raw measured values using a statistical method, selecting a first reference value from the stored raw measured values based on the analysis, assuming or setting a first expected concentration for the first reference value, converting the first reference value into a first analyte concentration using a built-in conversion function, comparing the first expected concentration with the first analyte concentration, and correcting the built-in conversion function based on the comparison.