Monolithic Load Cell With Embedded Calibration for Grain Bins
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Solution Overview
Problem
The high cost of calibrated load cells and the impracticality of field calibration methods for grain bins, which require manual parameter entry or time-consuming on-site calibration, are significant challenges in accurately determining grain bin contents.
Innovation Solution
A calibrated load cell with a monolithic load beam, strain gauge, and microcontroller encapsulated in potting material, which performs calibration transformations internally and allows bi-directional communication via a signal wire for secure parameter transfer during manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibrated load cells are used to accurately determine grain bin weight, then measurement precision is improved, but device cost increases substantially
Solution Approach 1:
The patent performs calibration at the point of manufacture by incorporating a microcontroller that automatically stores calibration parameters in non-volatile memory during the manufacturing process. This preliminary calibration action eliminates the need for expensive post-manufacturing calibration services while ensuring measurement accuracy is achieved before the load cell is installed in the grain bin.
Solution Approach 2:
The load cell system performs self-calibration through an automated process where the microcontroller reads strain gauge signals, applies calibration transformations using stored parameters, and outputs calibrated weight measurements without requiring manual intervention. This self-service capability reduces manufacturing costs by eliminating labor-intensive calibration procedures.
2Ease of operation
If field calibration methods are used to calibrate load cells after installation, then calibration can be performed on-site, but the process becomes time-consuming and requires manual parameter entry
Solution Approach 1:
Calibration parameters are predetermined and stored in the microcontroller's non-volatile memory during manufacturing, eliminating the need for time-consuming field calibration procedures. The load cell is pre-configured with the necessary calibration data so that when installed in the grain bin, it immediately provides accurate measurements without requiring manual parameter entry or on-site adjustment.
Solution Approach 2:
The patent replaces manual calibration procedures with an automated electronic system. The microcontroller automatically reads strain gauge signals, applies calibration transformations using stored parameters, and outputs calibrated measurements without requiring manual intervention. This substitution of automated electronics for manual mechanical calibration processes dramatically reduces calibration time and eliminates the need for field calibration activities.
3Adaptability or versatility
If calibration parameters are printed on paper and manually entered into the measurement system, then calibration can be performed, but the process is prone to errors and reduces productivity
Solution Approach 1:
The patent replaces manual paper-based calibration parameter entry with an automated electronic system. The microcontroller automatically reads strain gauge signals and applies calibration transformations using parameters stored in its non-volatile memory. This electronic automation eliminates manual data entry, reduces errors, and significantly improves calibration productivity by performing the entire calibration process without human intervention.
Solution Approach 2:
The load cell system performs self-calibration through the microcontroller, which automatically retrieves calibration parameters from non-volatile memory and applies them to transform strain gauge signals into accurate weight measurements. This self-service capability eliminates the need for external calibration equipment and manual parameter transfer, thereby improving productivity and reducing errors.
4Measurement precision
If multiple weights are placed on each individual load cell for calibration, then accurate scale factor determination is achieved, but the calibration process becomes extremely time-consuming
Solution Approach 1:
The patent performs scale factor determination during the manufacturing process using automated equipment that can efficiently apply known loads and measure the corresponding strain gauge outputs. The microcontroller stores the determined scale factors in non-volatile memory, eliminating the need for time-consuming field calibration with multiple weights. This preliminary action ensures accurate scale factors are obtained before the load cell is installed.
Solution Approach 2:
The patent replaces the manual process of placing multiple weights on each load cell with an automated calibration system performed during manufacturing. The microcontroller automatically processes strain gauge signals and applies calibration transformations using pre-determined scale factors. This automated electronic calibration process dramatically reduces calibration time while maintaining measurement precision.
5Measurement precision
If load cells are calibrated individually at the factory with uniform offset and sensitivity factors, then measurement consistency is improved, but manufacturing cost increases
Solution Approach 1:
The patent implements self-calibration through the microcontroller, which automatically reads strain gauge signals, applies calibration transformations using uniformly applied offset and sensitivity factors stored in non-volatile memory, and outputs calibrated measurements. This automated self-service approach ensures consistent calibration across all load cells while reducing manufacturing costs by eliminating labor-intensive individual calibration procedures.
Solution Approach 2:
The patent replaces manual individual calibration procedures with an automated electronic system. The microcontroller uniformly applies calibration parameters to all load cells during manufacturing, ensuring measurement consistency. This automated process reduces manufacturing costs by eliminating the need for skilled technicians to manually calibrate each load cell individually while maintaining uniform calibration quality across all units.
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
Enables cost-effective, secure, and accurate grain bin weight measurement by performing calibration at the point of manufacture, addressing non-linearities and preventing tampering, while reducing installation complexity and costs.
Implementation Method 1
A strain gauge is preferably arranged in the recess for detecting a deformation of the third region from the load and for generating a strain gauge output signal proportional to the deformation of the third region
Data Source
AI summary
A calibrated load cell includes a monolithic load beam having a first region, a second region on a distal end of the load beam from the first region for receiving a force from a load, and a third region arranged between the first and second regions, wherein the third region comprises a recess on one side of the load beam. A strain gauge is arranged in the recess for detecting a deformation of the third region from the load and for generating a strain gauge output signal proportional to the deformation of the third region. The load cell also includes a microcontroller arranged in the recess for receiving and processing the strain gauge output signal to produce a load cell output signal that represents the load on a load cell output cable. The microcontroller transforms the strain gauge output signal based on calibration parameters to produce the load cell output signal as a calibrated load cell output signal.