Adaptive Weighing Control for Low Minimum Net Weights
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing weighing systems face challenges in achieving low minimum net weights due to random variations caused by external influences, leading to high costs when using more precise balances or larger sample amounts, especially in applications like pharmaceuticals where regulatory requirements demand reliable measurements below the balance's minimum weight value.
Innovation Solution
A method and system that employs adaptive weighing mode, taking multiple measurements to reduce standard deviation by averaging, allowing valid results without needing higher precision balances, and includes a processing unit to manage these measurements and user interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a balance with higher precision and smaller scale interval is used, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The system dynamically adjusts the minimum weight threshold based on the actual standard deviation measured during operation. Instead of using a fixed threshold determined by the balance's scale interval, the system continuously monitors measurement variations and adapts the minimum weight value accordingly, allowing efficient use of existing balance hardware while achieving reliable measurements
Solution Approach 2:
The system changes the parameter of minimum weight threshold from a fixed value (based on scale interval) to a dynamic value (based on measured standard deviation). This parameter transformation allows the system to achieve lower effective minimum weight values without requiring hardware changes, resolving the contradiction between measurement precision and device complexity
2Measurement precision
If larger amounts of substance are measured, then measurement precision is improved, but loss of substance increases
Solution Approach 1:
The system enables dynamic determination of the minimum weight threshold during operation based on actual measurement variability. This allows the system to achieve reliable measurements at lower substance amounts by adapting the threshold to the actual standard deviation, thereby reducing substance loss while maintaining measurement precision
Solution Approach 2:
The system replaces the mechanical/physical approach of increasing sample mass to improve precision with a computational approach. By using statistical analysis of multiple measurements and dynamically adjusting the minimum weight threshold, the system achieves the same precision improvement effect without requiring larger substance amounts
3Measurement precision
If multiple repeated measurements are taken, then measurement precision is improved, but productivity decreases
Solution Approach 1:
The system dynamically determines when to stop repeated measurements by continuously comparing the current standard deviation against the adaptively adjusted minimum weight threshold. This dynamic stopping criterion allows the system to achieve the required precision with the minimum necessary number of measurements, optimizing the balance between measurement precision and productivity
4Ease of operation
If a fixed minimum weight value based on scale interval is used, then ease of operation is improved, but measurement precision worsens
Solution Approach 1:
The system performs self-characterization by automatically measuring the standard deviation during operation and using this information to determine the appropriate minimum weight threshold. This self-service approach eliminates the need for manual configuration or complex user judgments, maintaining ease of operation while achieving improved measurement precision through adaptive thresholding
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for operating a weighing system comprises a balance and an electronic control apparatus, wherein a first weight value of a sample is compared with an initial minimum weight value of the weighing system and if the first weight value is smaller than the initial weight value, the weighing system is set in an adaptive weighing mode in which an adapted minimum weight value is determined based on the initial minimum weight value and a number of repeated weight measurements of the sample. The adapted minimum weight value is compared with an average weight value of the sample. Further, a weighing system, a computer program and a computer-readable storage medium are shown.