Sold out sensing device and method

Abstract

A control for a beverage dispenser monitors operation thereof to sense a beverage sold out condition. The control senses the voltage demand of a pump motor as it pumps the beverage from a source thereof to a dispensing valve. If the sensed voltage is high, that indicates the pump is encountering resistance and fluid is present. Conversely, if the sensed voltage use is low, that is taken to indicate that the pump is not pumping any liquid and that the container is empty. A software routine is used to sense the average current requirements during dispensing and adjust the reference voltage for the normal full reservoir pump current value based on a historical average thereof as indicated by a predetermined number of prior dispense cycles. The control uses the adjusted reference voltage as a base for determining a sold out condition. Thus, the control of the present invention has the ability to learn over time and to compensate for physical changes in hardware and in the environment to provide for accurate sold-out determinations. The control senses an sold out condition in one of two ways. If the control senses a large variation between voltage samplings during a dispense cycle, that is taken to indicate a situation where the syrup or beverage is running out. If there is no significant difference between the sensed voltages, but the sensed voltage is significantly below the reference voltage that would be expected if fluid were present, that also indicates a sold out condition.