Method and apparatus for measuring weight using uncalibrated load cells
AssigneeBECS Technology, Inc.
InventorRichard A. Livingston
Life of this patent
Estimating the term…
Abstract
A method and apparatus for calibrating load cells in the filed after the uncalibrated load cells have been installed. Two known weight conditions are used in conjunction with a storage device in which the uncalibrated load cells are installed. The method will calibrate the load cells, calculate load cell offsets, scale factor differences between load cells, and flexure/stresses in a supporting structure which rests upon the uncalibrated load cells.
Claims23
A measuring and calibration method comprising the steps of:
- installing at least two load sensing devices onto a load carrying device, said at least two load sensing devices each having an individual output signal;
- connecting said individual output signal from each of said at least two load sensing devices to a computing device;
- analyzing a first set of values and a second set of values of said individual output signals from each of said at least two load sensing devices;
- and
- calibrating said at least two load sensing devices responsive to said analysis of said output signals of said at least two load sensing devices.
A method for weight calibration and measurement comprising the steps of:
- installing at least two load sensing devices onto a load carrying device, said at least two load sensing devices each having an output signal;
- connecting said output signals from each of said at least two load sensing devices to a computing device;
- analyzing a first set of output signal values and a second set of output signal values;
- calibrating said at least two load sensing devices responsive to said analysis of said output sets of signals by solving the equation
- 5 C i = [ ∑ i = 1 n ( N100 i - N90 i ) ] ( N100 i - N90 i ) × n
- where:
- Ci=the scale factor for load cell “i”;
- NI00i=the reading from the i′th load cell at substantially full load;
- N90i=the reading from the i′th load cell at substantially 90% of full load;
- and
- n=the number of load cells;
- to calculate a scale factor for each of said at least two load sensing devices by solving the following equation
- 6 W = ∑ i = 1 n δ N i · C i ∑ i = 1 n ( N MaxCal_i - N MinCal_i ) · C i · ( W Max Cal - W NimCal ) + W Min Cal
- where:
- δNi=Ni−NMinCal—i;
- NMinCal—i=the reading from the i′th load cell at the Minimum Calibration;
- NMaxCal—i=the reading from the i′th load cell at the Maximum Calibration;
- Ci=the scale factor for the i′th load cell, as calculated above;
- WMaxCal=the weight entered by the user at full load during Maximum Calibration;
- and
- WMinCal=the weight entered by the user at no load during Minimum Calibration;
- to calculate a weight of said substance within the load carrying device.
An apparatus for measurement and calibration comprising:
- a load carrying device;
- at least two load sensing indicators used with the load carrying device, said at least two load sensing indicators each configures to provide an output signal;
- and
- a computing device, said computing device being configured to analyze said output signals to calculate a weight of a substance in said load carrying device and to calculate a scale factor for each of said at least two load indicators.
Dependencies are inferred from the claim text.