Register position sensing and controlling apparatus

Abstract

A visually and electronically readable motor driven register has a plurality of dependently rotatable, coaxial, incrementally positionable, number wheels which each carry a movable electrode fixed in a predetermined position relative to the numbers on each wheel. Adjacent each movable electrode is inserted a fixed plate which carries a plurality of stationary electrodes, each corresponding to a number on the wheel and disposed circumferentially around a stationary main electrode which is capacitively coupled to the movable electrode. When a number on a wheel is visually readable, the movable electrode will be positioned so as to be capacitively coupled only to the stationary electrode corresponding to the readable number. A microprocessor provides pulses sequentially to the stationary electrodes of each wheel, and checks for a coincident processed output from the main electrode of the first wheel. If there is a processed output indicating capacitive coupling between stationary and movable electrodes, the microprocessor retains the electrode number indicative of the readable number of the first wheel and checks for a coincident processed output from the main electrode of the second wheel. When all the wheels have been read, the first wheel is again checked; if all the wheels have not been able to be read, the microprocessor will activate the motor to move the wheels until they can all be read.