Patent ID: 8776574

Claim:
A fluid level measurement apparatus configured to support a plurality of fluid level sensors, each fluid level sensor detecting a level of fluid in a container and producing an output indicative of the detected level of the fluid, the fluid level measurement apparatus adapted to be connected to any one of the plurality of fluid level sensors to measure the level of the fluid, the fluid level measurement apparatus comprising: a plurality of output circuits, each output circuit generating a detection voltage based on the output of a corresponding one of the plurality of fluid level sensors; a calculation circuit configured to calculate the level of the fluid from any of the detection voltages of the plurality of output circuits; a determination circuit configured to determine which fluid level sensor of the plurality of fluid level sensors is connected to the fluid level measurement apparatus; a selection circuit configured to select one of the plurality of output circuits corresponding to the determined fluid level sensor and configured to allow the calculation circuit to obtain the detection voltage generated by the selected output circuit; a constant current application circuit configured to apply a predetermined constant current to the connected fluid level sensor; and a resistance measurement circuit configured to measure a resistance of the connected fluid level sensor upon application of the constant current to the connected fluid level sensor, wherein the determination circuit determines the connected fluid level sensor based on the measured resistance; the plurality of fluid level sensors comprises a magnetoelectric fluid level sensor and an electrical resistance fluid level sensor, the magnetoelectric fluid level sensor uses a magnetoelectric element to detect the level of the fluid by detecting a rotation angle of a rotation member that rotates according to the fluid level, the electrical resistance fluid level sensor uses a variable resistor to detect the level of the fluid by detecting the rotation angle of the rotation member, and when the measured resistance is greater than a predetermined threshold resistance, the determination circuit determines that the connected fluid level sensor is the magnetoelectric fluid level sensor.