Method and apparatus for sensing liquid level using baseline characteristic

Abstract From the Canadian patent

A liquid level sensing arrangement using a probe uses a baseline probe circuit characteristic, e.g. a circuit resistance or voltage that is measured when , the probe is out of contact with the liquid in the tank. The baseline characteristic may be used to determine a liquid level in the tank e.g. a , determination whether the liquid level is below or at/above the probe. In one embodiment, the baseline characteristic may be compared to a circuit characteristic that is measured as the tank is being filled. A difference between the baseline characteristic and the other circuit characteristic may be used to determine whether or not the probe is in contact with the liquid.