METHOD AND APPARATUS FOR DETECTING LIQUID LEVELS IN LIQUID-STORAGE CONTAINERS

摘要

A method and apparatus for sensing different levels of liquids in their respective containers in a liquid-consuming and/or producing instrument system. According to a preferred embodiment, an elongated liquid-sensing probe having axially spaced electrodes adapted to sense liquid at multiple levels is arranged in each container of liquid. A controller, e.g. a suitably programmed microprocessor, operates to selectively poll different pairs of electrodes carried by the probe to determine whether or not the polled electrode pairs are immersed in the contained liquid. Preferably, the polling circuit comprises an electronically-controlled resistor that serves to normalize the level-sensing output signal for liquids of different bulk resistivity.