Ultrasonic sensing and control apparatus

Claim 1

A stock loop controller comprising: (a) a transducer adapted to transmit an ultrasonic signal in the direction of a stock loop to be controlled; (b) a start signal co-incident with the leading edge of the ultrasonic signal; (c) a receiver circuit for detecting echo signals from the stock loop; (d) a clock pulse generator for generating a fixed number of clock pulses per time interval; (e) digital counter means for accumulating and counting the clock pulses commencing with the start signal and terminating with receipt of the echo signal and generating a digital signal proportional to the count; (f) converter means for converting the digital signal to an analog signal; and (g) amplifier means coupled between said converter means and a reference voltage for generating a difference signal proportional to the difference between the analog signal and the reference signal; the difference signal being adapted to provide a control voltage to a servomotor controlling the stock loop.

Claim 7

The method of controlling stock loop comprising: (a) transmitting an ultrasonic signal in the direction of said loop; (b) receiving an echo signal from said loop; (c) counting pulses from a clock pulse generator at the time the ultrasonic signal is transmitted and stopping the count when the echo signal returns; (d) generating a digital signal proportional to the number of clock pulses counted; (e) converting said digital signal to an analog signal; (f) amplifying the difference between said analog signal and a reference signal in an amplifier to produce a difference signal; and (g) using said difference signal to control the pay-out or take-up of said stock loop.

Claim 8

The method of controlling stock loop comprising: (a) transmitting an ultrasonic signal in the direction of said loop; (b) receiving an echo signal from said loop; (c) counting pulses from a clock pulse generator at the time the ultrasonic signal is transmitted and stopping the count when the echo signal returns; (d) generating a digital signal proportional to the number of clock pulses counted; (e) converting said digital signal to an analog signal; (f) amplifying the difference between said analog signal and a reference signal in an amplifier to produce a difference signal; and (g) using said difference signal to control the pay-out or take-up of said stock loop.