Combined fluid condition monitor and fluid level sensor

摘要

A combination fluid condition monitor and fluid level sensor having an excitation electrode divided into two segments disposed closely spaced and parallel to current sensing electrode. For the fluid condition monitoring mode function both segments of the excitation electrode are commonly excited sequentially at high and low frequencies and the currents sensed in the sensing electrode employed to compute the difference in impedance for determining the fluid condition. For the level sensing mode function a mode switching circuit grounds one of the excitation electrode segments and excites the other then grounds the other segment and excites the one segment and the resultant currents ratioed to determine the amount of electrode immersed in fluid and hence the fluid level.