Compensated multi-load cell scale

A method of compensating a scale having at least three load cells and no more than two strain gages per load cell, comprising the steps of arranging the strain gages of the load cells in a bridge circuit to provide an output signal representative of a load on the scale, placing a load on the scale sequentially in a number of locations and obtaining a load indication for each of said locations, utilizing said load indications to calculate the values of compensating resistors required to be connected in circuit with certain of the strain gages to render the output of said bridge circuit substantially independent of the location of a load on the scale, and connecting said compensating resistors in circuit with the appropriate strain gages to render the output of said bridge circuit substantially independent of the location of a load on the scale.

A method of compensating a scale having N load cells, where N is at least 4, and no more than two strain gages per load cell, comprising the steps of arranging the strain gages of the load cells in a bridge circuit to provide an output signal representative of a load on the scale, placing a load on the scale sequentially in a number of locations and obtaining a load indication for each of said locations, utilizing said load indications to determine the values of compensating resistors required to be connected in circuit with at least one strain gage of at least N-1 of the load cells to render the output of said bridge circuit substantially independent of the location of a load on the scale, and connecting said compensating resistors in circuit with the appropriate strain gages to render the output of said bridge circuit substantially independent of the location of a load on the scale.

The method of compensating scales having a platform supported by at least three load cells connected in an electrical bridge circuit, which method comprises the steps of (1) determining the response of each load cell by placing a test weight over each load cell, (2) calculating attenuated responses for the respective load cells in small decrements until the responses of the respective load cells are all substantially equal, and (3) calculating from said responses the magnitudes of compensating resistors to be connected to the respective load cells so that the response of the scale is substantially independent of the position of the load on the platform.

A scale arrangement comprising in combination a scale platform, a plurality of at least four load cells supporting the platform, each load cell having a single strain gage responsive to tension and a single strain gage responsive to compression, an electrical bridge circuit comprising the strain gages of each load cell connected in adjacent arms of the bridge circuit, and a single resistor connected to both of the strain gages of at least three of the load cells so that the output of the bridge circuit is substantially independent of the position of a load on the platform.

A scale arrangement comprising in combination a scale platform, a plurality of at least four load cells supporting the platform, each load cell having a single strain gage responsive to tension and a single strain gage responsive to compression, an electrical bridge circuit comprising the strain gages of each load cell connected in adjacent arms of the bridge circuit, and a resistor connected between intermediate points of at least three pairs of adjacent arms of the bridge circuit so that the output of the bridge circuit is substantially independent of the position of a weight on the scale platform.

Weighing apparatus as claimed in claim 28 wherein said compensating resistors are connected in circuit with individual strain gages to modify the response of the respective individual strain gage.

A method of compensating a scale having a platform supported by at least three load cells connected in an electrical bridge circuit, comprising the steps of determining the responses of at least some of the load cells by placing a test weight over each of those load cells in sequence and reading the outputs of the bridge circuit, calculating attenuated responses for those load cells in small decrements until the differences in the responses of the load cells are minimized within desired limits, and calculating from said responses the magnitudes of compensating resistors to be connected to at least some of those load cells so that changes in the response of the scale with changes in the position of the load on the platform are reduced.