Digital scale

In a digital scale in combination apparatus for generating a verification signal representating a verification weight, storage means for storing a reference verification value, means for also storing a span multiplying factor, means for multiplying the verification weight represented by said verification weight signal by the span multiplying factor, and means to change the stored span factor when the difference between the stored reference verification value and the verification weight is within predetermined limits to reduce the difference toward zero.

In a digital scale system in combination a scale mechanism, apparatus for generating a weight signal representing a weight on the scale mechanism, means responsive to the removal of a weight from said scale mechanism and the generation of a weight signal representing zero weight on the scale mechanism for automatically applying a verification weight signal representing a verification weight to the scale system to check the operation of the scale system.

In a digital scale system, in combination, a scale mechanism apparatus for generating an analog weight signal representing the weight on the scale mechanism, analog circuits for responding to the analog weight signal, analog to digital conversion means for converting the analog signal to digital signals representing the weight on the scale, means for storing a digital span multiplying factor means for multiplying the weight represented by the digital signals by the span multiplying factor to generate a corrected weight signal.

A digital scale system comprising in combination, a scale mechanism, apparatus for generating an analog weight signals representing the weight on the scale mechanism, analog circuits for responding to analog weight signals connected to the apparatus for generating analog weight signals, an integrator circuit and program controlled means interconnected with the analog circuits to convert the analog weight signals to digital weight signals representing the weight on the scale, means for storing a digital span multiplying factor, multiplying means for multiplying the weight represented by the digital weight signals by the digital span multiplying factor to obtain a corrected weight, means for storing a reference verification weight value, means responsive to the removal of a weight from the scale and a return to a zero indication of the scale system to automatically apply to the analog circuits an analog signal representing a verification weight, and obtaining a corrected verification weight, means for comparing the corrected verification weight with the stored verification weight value, and means for displaying an error symbol responsive to the comparison means when the stored verification reference value and the corrected verification weight differ by more than a predetermined amount.

A digital scale system comprising in combination a scale mechanism, apparatus for generating a weight signal representing a weight on the scale mechanism, means responsive to the removal of a weight from the scale mechanism and the generation of a weight signal representing zero on the scale mechanism for automatically applying a verification weight signal representing a verification weight to the scale system, checking means responsive to the application of the verification weight signal to the scale system to check the operation of the scale system, and means responsive to the application of a weight to the scale mechanism during the operation of the checking means to prevent further operation of the checking means.

In a digital scale, in combination, apparatus for generating a verification signal representing a verification weight, storage means for storing a reference verification value, microprocessor means including means for storing a span multiplying factor, the microprocessor means including means for multiplying the verification weight represented by the verification weight signal by the span multiplying factor, the microprocessor means also including means to change the stored span factor when the difference between the stored reference value and the verification weight is within predetermined limits to reduce the difference toward zero.