Load Cell Thermocouple Temperature Difference Compensation
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Solution Overview
Problem
Temperature changes in load cells due to power-up drift cause errors in weight measurement signals, as components heat up and emit heat, leading to temperature gradients that affect the accuracy of scale readings.
Innovation Solution
A load cell with a temperature sensor configured to measure the direct temperature difference between two points on the load cell, using a thermocouple to eliminate systematic errors and improve temperature compensation accuracy, allowing for continuous and reliable correction of weight measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two temperature sensors are used to measure absolute temperatures at two points, then temperature difference can be calculated, but systematic errors such as zero point shifts occur and measurement precision deteriorates
Solution Approach 1:
The patent replaces the electrical measurement system (two temperature sensors measuring absolute temperatures and calculating difference) with a thermocouple-based thermal measurement system. The thermocouple directly measures temperature difference through thermal voltage generation, eliminating the need for electrical calculation and avoiding systematic errors associated with electrical sensor calibration.
Solution Approach 2:
The patent changes the measurement parameter from absolute temperature to temperature difference directly. By using a thermocouple that generates voltage proportional to temperature difference, the system directly measures the differential parameter without needing to measure and calculate from absolute values, thereby improving precision and eliminating zero point shift errors.
2Reliability
If temperature compensation is performed using calculated temperature differences from two absolute temperature measurements, then temperature effects can be compensated, but measurement errors propagate and reduce weight determination accuracy
Solution Approach 1:
The patent replaces the electrical calculation-based temperature difference measurement with a direct thermal measurement using a thermocouple. This substitution eliminates error propagation from electrical sensor measurements and calculations, providing more reliable temperature difference data for weight determination compensation.
Solution Approach 2:
The thermocouple acts as an intermediary device that directly transduces temperature difference into an electrical signal. This intermediary measurement approach provides a more accurate basis for temperature compensation than calculating temperature difference from two separate absolute temperature measurements, thereby improving weight determination accuracy.
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 direct measurement of temperature differences enhances the accuracy of temperature compensation, reducing errors caused by power-up drift and enabling precise weight determination, even with multiple heat sources, by using current measurement values for reliable and efficient temperature compensation.
Implementation Method 1
A temperature difference between two points can be measured directly by means of a temperature sensor, in particular by means of a thermocouple. A thermocouple comprises two electrical conductors of different materials that are connected to one another at one side, with a voltage being applied to the two open ends of the conductors that is dependent on a temperature difference along the two conductors.
Data Source
AI summary
The invention relates to a load cell for a scale, comprising a measuring device for producing a temperature-dependent weight measurement signal corresponding to an acting weight and at least one temperature sensor for measuring a temperature of the load cell, wherein a temperature-compensated weight can be calculated by an evaluating unit from the produced weight measurement signal and the measured temperature. The temperature sensor is designed as a sensor, in particular a thermocouple, that measures a temperature difference between a first point, in particular a measurement point, of the load cell and a second point, in particular a comparison point, of the load cell.