Abstract: An ultrasonic liquid level sensor instrument that combines a continuous transmitter that transmits though the air for measuring the level of liquid in a vessel on a continuous basis and a point level sensor that sets a high level alarm. The continuous level transmitter/receiver provides a continuous measurement of the liquid level in the vessel and the point level sensor is used for sensing an overflow, or high level condition in the vessel, as well as failure of the continuous transmitter/receiver. The instrument includes a sensor fixture that holds both the continuous air transmitter/receiver transducer and the point level sensor. The fixture is mounted in a single hole in the wall of a tank or a vessel in which the liquid level is being monitored. Each of the continuous level transmitter/receiver and point level sections of the instrument has a self check capability.

Abstract: A system for counting the number of objects of known thickness in a stack and identifying the objects by their color in which an ultrasonic sensor is mounted at a known distance from a reference point that defines the beginning of the stack. The ultrasonic sensor is operated to measure the round trip transit time of ultrasonic energy reflected back from the closest object in the stack and the number of objects in the stack is calculated on the basis of the known distance and the round trip transit time. A color sensor senses the color of at least one object in the stack to identify the object. In a casino application where the objects are chips of known monetary value, the value of the chips in the stack can be calculated.