Plural scale system with digital zero correction

Claim 2

Weight measuring apparatus comprising a plurality of scales each having analog weight outputs, an analog-to-digital converter, switch means for connecting a selected one of the analog weight outputs from said scales to an analog input to said converter whereby such analog weight output is digitized, means for digitally correcting each digitized weight for zero errors in the analog weight outputs, and means for utilizing such corrected digitized weights.

Claim 3

Weight measuring apparatus comprising a plurality of scales each having analog weight outputs, means for digitizing Such weight outputs, computing means, means for selectively applying the digitized weight outputs to said computing means, said computing means including means for digitally combining a zero error correction factor for each scale with the digitized weight output from such scale to obtain a corrected weight output and means responsive to a corrected weight output from any of said scales deviating from zero by less than a predetermined small amount for establishing a new zero error correction factor for such scale to reduce such zero deviation, and means for utilizing such corrected weight output.

Claim 4

Weight measuring apparatus comprising a plurality of scales each having analog weight outputs, means for digitizing Such weight outputs, computing means, means for selectively applying the digitized weight outputs to said computing means, said computing means including means for digitally combining a zero error correction factor for each scale with the digitized weight output from such scale to obtain a corrected weight output and means responsive to a corrected weight output from any of said scales deviating from zero by less than a predetermined small amount for establishing a new zero error correction factor for such scale to reduce such zero deviation, and means for utilizing such corrected weight output.

Claim 5

Weight measuring apparatus, as set forth in claim 2, wherein said digitizing means comprises a single analog-to-digital converter having an output connected to said computing means, and wherein said means for selectively applying the digitized weight outputs to said computing means selectively connects the analog weight outputs from said scales to an input to said analog-to-digital converter whereby the connected analog weight output is digitized and applied to said computing means.

Claim 6

Weight measuring apparatus, as set forth in claim 3, wherein said means for selectively applying the digitized weight outputs from said scales to said computing means includes switch means for selectively and sequentially connecting the analog weight outputs from said scales to the input to said analog-to-digital converter whereby the analog weight outputs from said scales are sequentially digitized and applied to said computing means for zero error correction.

Claim 7

A parts counter comprising, in combination, a major scale for weighing an unknown number of parts to be counted, a minor scale for weighing a known number of parts, said scales each including load cell weight measuring means for generating an analog weight signal, an analog-to-digital converter, switch means for selectively applying the analog weight signals from said major scale and from said minor scale to the analog input of said analog-to-digital converter, an arithmetic logic unit connected to the digitized weight output from said converter, a keyboard for supplying manually entered data to said arithmetic logic unit, said arithmetic logic unit including means for computing a count of the number of parts on said major scale from data received from said analog-to-digital converter and said keyboard, and digital display means for indicating such computed parts count, said arithmetic logic unit including means for combining a zero error correction factor for each scale with the digitized weight signal from such scale to obtain a corrected weight for such scale, said arithmetic logic unit using the corrected weight for computing a count of the number of parts on said major scale, and means responsive to the corrected weight signals for either of said major and minor scales deviating from zero by less than a predetermined small amount for generating a new zero error correction factor for such scale.

Claim 8

A parts counter comprising, in combination, a major scale for weighing an unknown number of parts to be counted, a minor scale for weighing a known number of parts, said scales each including load cell weight measuring means for generating an analog weight signal, an analog-to-digital converter, switch means for selectively applying the analog weight signals from said major scale and from said minor scale to the analog input of said analog-to-digital converter, an arithmetic logic unit connected to the digitized weight output from said converter, a keyboard for supplying manually entered data to said arithmetic logic unit, said arithmetic logic unit including means for computing a count of the number of parts on said major scale from data received from said analog-to-digital converter and said keyboard, and digital display means for indicating such computed parts count, said arithmetic logic unit including means for combining a zero error correction factor for each scale with the digitized weight signal from such scale to obtain a corrected weight for such scale, said arithmetic logic unit using the corrected weight for computing a count of the number of parts on said major scale, and means responsive to the corrected weight signals for either of said major and minor scales deviating from zero by less than a predetermined small amount for generating a new zero error correction factor for such scale.

Claim 9

A parts counter, as set forth in claim 5, wherein each of said scales includes analog signal amplifying means, and means for automatically compensating the analog output of said signal amplifying means for any unwanted DC component.

Claim 10

A parts counter, as set forth in claim 5, wherein said keyboard includes switch means for causing said arithmetic logic unit to expand for at least one of said scales the predetermined small amount of deviation from zero for which a new zero error correction factor is generated.

Claim 11

A parts counter, as set forth in claim 5, wherein said arithmetic logic unit computes a count of the number of parts on said major scale from the corrected weight from said major scale and from average part weight data, said average part weight data comprising either an average part weight supplied from said keyboard or a corrected sample part weight from said minor scale and a count of the number of sample parts on said minor scale supplied from said keyboard.