초록 ▼

An optical encoder generates a train of digital pulses as a function of the length of web material unwound per revolution of an unwinding roll. A counter counts the encoder pulses for each revolution of the roll. The counts of the encoder pulses are accumulated over a first set of revolutions of the

An optical encoder generates a train of digital pulses as a function of the length of web material unwound per revolution of an unwinding roll. A counter counts the encoder pulses for each revolution of the roll. The counts of the encoder pulses are accumulated over a first set of revolutions of the roll. A programmed microprocessor effects a base computation of (1) the average change in the number of pulses generated per revolution of the roll and (2) the length of web remaining on the roll after the first set of revolutions. Thereafter, the base computation of web length is updated at each revolution of the roll. The counter may comprise an addressable hardware counter chain alone or in combination with a read/write memory which counts the number of times that the counter chain overflows.

대표청구항 ▼

Apparatus for determining the length of web remaining on an unwinding roll, comprising: first means for generating a train of digital pulses representative of the length of web unwound per revolution of the roll; second means for monitoring the number of revolutions of the roll; third means operativ

Apparatus for determining the length of web remaining on an unwinding roll, comprising: first means for generating a train of digital pulses representative of the length of web unwound per revolution of the roll; second means for monitoring the number of revolutions of the roll; third means operatively associated with said first and second means for accumulating successive counts of said pulses over a predetermined number of revolutions of the roll; fourth means operatively associated with said first, second and third means for computing the average change in the number of said pulses generated per revolution of the roll over a predetermined number of revolutions of the roll and for computing the length of web remaining on the roll after each revolution thereof based on said computed average change and the accumulated counts of said pulses.