Status detection method and apparatus for load cell

Patent metadata

Field	Value
Publication number	US-12007270-B2
Application number	US-202117448759-A
Country	US
Kind code	B2
Filing date	Sep 24, 2021
Priority date	Sep 28, 2020
Publication date	Jun 11, 2024
Grant date	Jun 11, 2024

Abstract

A method and apparatus are provided for detecting the status of a load cell. When method for detecting the status of a load cell is applied to a multi-point weighing system, the method first collects characteristic sensing data of load cells. It then calculates an anomaly in the characteristic sensing data. From this, it acquires and generates an output signal corresponding to the load cell information when the anomaly exists. The method and apparatus for detecting the status of a load cell can help customers accurately locate a faulty, or potentially faulty, sensor, so as to avoid a measurement error due to sensor problems and improve user satisfaction.

First claim

What is claimed is:

1. A method for detecting the status of a load cell in a plurality of load cells in a material tank system, the method comprising the steps of:
collecting, by way of a collection unit, characteristic sensing data of the load cells;
calculating, by way of a calculation unit, an anomaly in the collected characteristic sensing data, including by at least:
converting a time domain signal of each piece of the characteristic sensing data to a frequency domain through Fast-Fourier-Transformation calculation; and
determining an anomaly through an amplitude-frequency characteristic comparison in frequency domain; and

acquiring and outputting, by way of a sending unit, a corresponding load cell information when the anomaly exists.

2. The method of claim 1 , wherein the characteristic sensing data comprise at least one of: weighing data, acceleration, temperature, humidity, angle, gas density, voltage, and current.

3. The method of claim 1 , further comprising the steps of:
issuing a reminder of an anomalous load cell state if the anomaly has a deviation that is less than a preset alarm value; and
issuing an alarm reminder of load cell replacement if the anomaly deviation is greater than the preset alarm value.

4. The method of claim 1 , wherein the step of calculating an anomaly comprises the steps of:
calculating a difference between each piece of the characteristic sensing data and a statistical median; and
determining that the corresponding characteristic sensing data is an anomaly, when the difference exceeds an anomaly deviation of an anomaly.

5. The method of claim 1 , wherein the step of calculating an anomaly in the characteristic sensing data comprises the steps of:
calculating whether each piece of the characteristic sensing data obeys a sigma distribution; and
determining that the characteristic sensing data that does not fall within the sigma distribution is an anomaly.

6. The method of claim 1 , wherein the step of calculating an anomaly in the characteristic sensing data comprises the steps of:
calculating a standard score of each piece of characteristic sensing data; and
determining that the characteristic sensing data having a deviation that exceeds an anomaly deviation of an anomaly is an anomaly.

7. The method of claim 1 , wherein the step of calculating an anomaly in the characteristic sensing data comprises the steps of:
calculating a mean of the characteristic sensing data, after excluding the largest value or the smallest value;
calculating a difference between the largest value and the mean of the characteristic sensing data, or a difference between the smallest value and the mean of the characteristic sensing data;
determining that the corresponding largest value or smallest value is an anomaly if the difference exceeds an anomaly deviation of an anomaly; and
re-calculating the difference between the largest value or the smallest value and the mean in the characteristic sensing data except the anomaly, until there is no anomaly in the sensing characteristic data.

8. An apparatus for detecting the status of a load cell in a plurality of load cells in a material tank system, said apparatus comprising:
a collection unit configured to collect characteristic sensing data of load cells;
a calculation unit configured to calculate an anomaly in the characteristic sensing data by at least:
converting a time domain signal of each piece of the characteristic sensing data to a frequency domain through Fast-Fourier-Transformation calculation; and
determining an anomaly through an amplitude-frequency characteristic comparison in frequency domain; and

a sending unit configured to acquire and output corresponding load cell information when the anomaly exists.

9. The apparatus of claim 8 , wherein the characteristic sensing data comprises data from at least one of: weighing data, acceleration, temperature, humidity, angle, gas density, voltage, and current.

10. The apparatus of claim 8 , wherein the calculation unit is configured to:
calculate a difference between each piece of characteristic sensing data and a statistical median; and
determine that the corresponding characteristic sensing data is an anomaly, when the difference exceeds an anomaly deviation of an anomaly.

11. The apparatus of claim 8 , wherein the calculation unit is configured to:
calculate whether each piece of the characteristic sensing data obeys a sigma distribution; and
determine that the characteristic sensing data that does not fall within the sigma distribution is an anomaly.

12. The apparatus of claim 8 , wherein the calculation unit is configured to:
calculate a standard score of each piece of characteristic sensing data; and
determine that the characteristic sensing data having a deviation that exceeds the deviation range is an anomaly.

13. The apparatus of claim 8 , wherein the calculation unit is configured to:
calculate a mean of the characteristic sensing data, after excluding the largest value or the smallest value;
calculate a difference between the largest value and the mean of the characteristic sensing data, or a difference between the smallest value and the mean of the characteristic sensing data;
determine that the corresponding largest value or smallest value is an anomaly if the difference exceeds an anomaly deviation of an anomaly; and
re-calculate the difference between the largest value or the smallest value and the mean in the characteristic sensing data except the anomaly, until there is no anomaly in the characteristic sensing data.

Assignees

• Mettler Toledo Changzhou Prec Instruments Co Ltd
• Mettler Toledo Changzhou Measurement Tech Co Ltd
• Mettler Toledo Int Trading Shanghai Co Ltd

Inventors

• Wu Jianwei
• Yang Jianqiang
• Bi Liugang

Classifications

• G01G23/18

  Indicating devices, e.g. for remote indication; Recording devices; Scales, e.g. graduated · CPC title

• G01G23/01 Primary

  Testing or calibrating of weighing apparatus · CPC title

• G01D21/02

  Measuring two or more variables by means not covered by a single other subclass · CPC title

• G01G23/48 Primary

  Temperature-compensating arrangements (G01G1/14, G01G1/42, G01G3/18 take precedence) · CPC title