Patent ID: 7428829
Filing Date: 2008-09-30
Classification: D06F

Abstract:
1. A circuit comprising: a processor programmed to prevent overfilling of a cabinet with a fluid; a pressure sensor operatively coupled to said processor; and a backup circuit having fixed logic, said backup circuit electrically coupled to said processor to redundantly prevent overfilling the cabinet with the fluid, said backup circuit including a first comparator that compares the signal from said pressure sensor with an overfill reference signal to indicate an overfill condition and a second comparator that compares the signal from said pressure sensor to a sensor error voltage to indicate an invalidity of the signal from said pressure sensor, said backup circuit acting independently of said processor to disable a flow of fluid to the cabinet when the overfill condition is indicated, and said backup circuit acting independently of said processor to disable a flow of fluid to the cabinet when the invalidity of the signal is indicated.