Teledyne API Model 465L O3 Monitor Operation Manual

The intensity of light is converted into a voltage by a high resolution A/D (analog-to-digital) converter. The digitized signal and other variables are used by the CPU to compute the concentration using the above formula.

About every 2.5 seconds the M465 completes a measurement cycle consisting of a 1 second wait period for the sample tube to flush, followed by a 150 ms measurement of the UV light intensity to obtain I. The sample valve is switched to admit scrubbed sample gas for 1 second, followed by a 150 ms measurement of the UV light intensity to obtain Io. Measurement of the Io every 2.5 seconds eliminates instrument drift due to changing intensity of the lamp caused by aging and dirt.

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05509F DCN6409

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Teledyne 465L operation manual 05509F DCN6409