US 4,071,102 A · Auto zero circuit

Abstract

Apparatus for generating a belt tare compensation signal including a load cell in operative contact with a feed conveyor belt dividable into N equal segments. The output of the load cell is strobed each time the conveyor belt advances one sampled and a pulse train representative of the output of the load cell is generated. The pulse train is applied to a pulse counter if the output of the load cell is greater than a predetermined value and is applied to a minus counter if the output of the load cell is less than a predetermined value. At the end of a single revolution of the conveyor belt, a signal representative of the difference between the count in the plus and minus counters is generated. This signal is divided by N so as to generate a belt tare compensation signal which is representative of the average output of the load cell during a single non-loaded revolution of the conveyor belt.

Claims12

Dependent claims

Apparatus for generating a belt tare compensation signal for use with a load cell in operative contact with a conveyor belt dividable into N equal segments comprising:

first means for generating N loading and N polarity signals, one said loading and one said polarity signal being generated each time said belt advances one said segment, said loading signal being a pulse train representative of the magnitude of the instanteous output of said load cell, said polarity signal indicating whether the output of said load cell is greater than or less than a predetermined value;
second means for generating a difference signal representative of the difference between the number of pulses generated by said first means when said polarity signal indicates that the output of said load cell is greater than said predetermined value and the number of pulses generated by said first means when said polarity signal indicates that the output of said load cell is less than said predetermined value;
and
divide by N means responsive to said difference signal for generating a belt tare compensation signal representative of the output of said load cell for a single non-loaded revolution of said conveyor belt.

1 more element

Apparatus for generating a belt tare compensation signal comprising:

a load cell in operative contact with a feed conveyor belt dividable into N equal segments;
means for adjusting the output of said load cell such that the output of said load cell is zero when said load cell is in contact with at least one of said N equal segments;
means for sampling the output of said load cell each time said belt advances a distance equal to one said segment and for generating a first signal representative of the net value of said sampled outputs of said load cell during a single non-loaded revolution of said belt;
divide by N means responsive to said first signal for generating a tare compensation signal representative of the average output of said load cell during a single non-loaded revolution of said conveyor belt.

1 more element

Dependencies are inferred from the claim text.

Auto zero circuit

Life of this patent

Auto zero circuit

Life of this patent

Abstract

Claims12