Patent ID: 7601298

Claim:
A method of treating a biological fluid in an apparatus with a fluid treatment chamber for receiving a biological fluid, a light source with a plurality of lamps disposed either above or below said fluid treatment chamber to treat the biological fluid with light and a light sensing system with a plurality of light sensors, said method comprising the steps of: sensing the amount of light emitted by said plurality of lamps with said plurality of light sensors; developing a plurality of frequency signals from the plurality of light sensors, the frequency of each frequency signal from each of said plurality of light sensors related to the amount of light received by each light sensor; providing said plurality of frequency signals to a first multiplexer; multiplexing the plurality of frequency signals with said first multiplexer to provide a first multiplexed frequency signal; and counting the plurality of frequency signals in said first multiplexed frequency signal with a first counter to provide a first counted output signal representative of the amount of light emitted by said plurality of lamps.