Patent ID: 8511305

Claim:
A humidifier system comprising: a heating element; a first power switch which turns on or off in response to a first control signal and a second power switch which turns on or off in response to a second control signal, the first and second power switches being in electrical series between a source of power and the heating element and both being required to be on for activation of the heating element; first and second processors, the first control signal being originated by the first processor and being provided therefrom to the first power switch along a first control path and the second control signal being originated by the second processor and being provided therefrom to the second power switch along a second control path; and a watchdog being in the first control path in electrical series between the first processor and the first power switch, the watchdog operable to normally gate the first control signal from the first processor to the first power switch and to monitor at least one of the first and second processors, and the watchdog further operable to interrupt the first control signal from the first processor to the first power switch so as to disable the heating element in response to the monitoring of the at least one of the first and second processors.