NDIR Gas Sensor Calibration for Low-Concentration Accuracy
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Solution Overview
Problem
The existing calibration systems and methods for NDIR gas sensors are computationally intensive, time-consuming, and costly, with inaccuracies in concentration and temperature compensation, particularly in low concentration ranges, and are not suitable for mass production.
Innovation Solution
A calibration system and method utilizing a client-server computer network with calibration software, a relay module, mass flow controller, and high and low temperature chambers, employing a Lambert-Beer weighted concentration calculation and adaptive piecewise linear temperature compensation, enabling simultaneous calibration of multiple sensors with reduced data interactions and processing tasks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional calibration systems use frequent data acquisition and massive data processing by computer, then calibration accuracy can be maintained, but calculation load becomes heavy, operation time is prolonged, and energy and cost consumption increase
Solution Approach 1:
The calibration process is divided into two independent phases: a calibration phase where sensors collect data and calculate coefficients locally, and a verification phase where pre-calibrated sensors provide reference data. This segmentation eliminates the need for continuous computer processing during calibration, reducing operation time while maintaining accuracy through the verification phase's reference data.
Solution Approach 2:
Each NDIR gas sensor performs self-calibration by independently calculating concentration and temperature compensation coefficients using its own calibration data. The sensors autonomously complete the calibration process without requiring continuous computer intervention, thereby reducing calculation load and operation time while maintaining calibration accuracy through individual sensor self-service.
2Measurement precision
If traditional calibration systems use frequent data acquisition and massive data processing by computer, then calibration accuracy can be maintained, but energy and cost consumption increase
Solution Approach 1:
The calibration process is divided into two independent phases: a calibration phase where sensors collect data and calculate coefficients locally, and a verification phase where pre-calibrated sensors provide reference data. This segmentation eliminates the need for continuous computer processing during calibration, reducing energy consumption while maintaining accuracy through the verification phase's reference data.
Solution Approach 2:
Each NDIR gas sensor performs self-calibration by independently calculating concentration and temperature compensation coefficients using its own calibration data. The sensors autonomously complete the calibration process without requiring continuous computer intervention, thereby reducing energy consumption and calculation load while maintaining calibration accuracy through individual sensor self-service.
3Productivity
If conventional fitting algorithms (polynomial curve fitting, surface fitting, piecewise linear fitting) are used with many calibration data points, then calibration can be performed, but calculation errors increase in low concentration ranges and calibration accuracy cannot be guaranteed when calibration data points are reduced
Solution Approach 1:
The patent transforms the calibration problem by changing the mathematical parameters from conventional polynomial coefficients to exponential parameters (A and B) in the formula C = A × e^(-B/T). This parameter transformation allows for accurate calibration with fewer data points, particularly improving low concentration range accuracy while maintaining high concentration range performance, thus enhancing calibration efficiency without sacrificing precision.
4Measurement precision
If Lambert-Beer curve fitting is used for concentration calculation, then calibration accuracy can be improved, but additional time (3 to 10 hours) is required to reduce gas concentration to zero by consuming additional energy and pure nitrogen
Solution Approach 1:
The patent performs preliminary calibration actions by collecting calibration data at multiple concentration levels and calculating the exponential parameters (A and B) before the actual measurement process. This preliminary calibration stores the necessary information in the sensor's memory, eliminating the need for time-consuming real-time zero-concentration reduction during actual calibration, thereby reducing calibration time while maintaining accuracy.
5Ease of manufacture
If conventional hardware-based linear temperature compensation mode is used, then temperature compensation can be implemented, but it cannot fully describe the complicated, non-linear, and non-monotonous temperature characteristics of NDIR gas sensors
Solution Approach 1:
The patent changes the temperature compensation approach by introducing a non-linear exponential parameter (B) that varies with temperature. This parameter change allows the system to accurately model the non-linear and non-monotonous temperature characteristics of NDIR gas sensors, significantly improving temperature compensation accuracy while maintaining ease of manufacture through the exponential parameter transformation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system improves calibration accuracy and efficiency, reduces time and cost, and enables greener mass production by minimizing data interactions and processing tasks while adapting to complex temperature characteristics of NDIR gas sensors.
Implementation Method 1
a calibration method for the NDIR gas sensors... employing a Lambert-Beer weighted concentration calculation
Implementation Method 2
high and low temperature chambers
Data Source
AI summary
The present invention relates to the technical field of sensor calibration, particularly a calibration system and a calibration method for NDIR gas sensors. The calibration system comprises: a client-server computer network with calibration software, a relay module, a gas source group, a mass flow controller, a high and low temperature chamber, a gas analyzer, and a calibration tooling rack group for implementing broadcasting-style calibration. The calibration method consists of: a Lambert-Beer weighted concentration calculation mode combined with an adaptive piecewise linear temperature compensation mode. Integrating the calibration system and the calibration method can effectively streamline the calibration process, improve the calibration accuracy, and reduce the calibration time and cost of the NDIR gas sensors. It can, therefore, conveniently realize a simultaneous calibration of many NDIR gas sensors for mass production and enable a greener production environment with a higher degree of carbon neutrality.