Stat Fax 303 Plus - Principles of Operation

2 Stat Fax 303 Plus Operator’s Manual Rev. J Awareness Technology, Inc.
User Programmable Memory
User-programmable memory allows the operator to store test protocols, recall tests by number,
and delete unwanted tests from a user-generated test menu. Instructions for using this memory
are given in section 2.3.3-Recalling a Test.
Besides quick, accurate, and reproducible results, the instrument offers maintenance-free and
easy operation, versatility, and economy. A stable factory-calibrated durable design, with a timed
lamp saving feature, further assures the reliability of this instrument.
1.2 Principles of Operation
Light energy from an overhead lamp is focused by a lens, directed through an aperture, and then
passed vertically through the sample. Below the sample, a continuously rotating wheel positions
the filters so that readings can be taken very quickly at both the primary and differential
wavelengths. Use of bichromatic differential absorbance values corrects for optical imperfections
in the plastic wells, differences in well meniscus, turbidity, and lamp variation. A photo detector
converts transmitted light energy into electrical signals, which are amplified and interpreted.