Data Acquisition; Setting The Gain - Valeport Hyperion Operating Manual

4. Data Acquisition

Hyperion Fluorometers are designed for both static monitoring and profiling operations either as a
standalone instrument or as part of a profiling multi sensor instrument.
The Fluorometer should be mounted with the window on the front face of the instrument and
therefore, the beam of excitation light directed into the water body to be analysed. During the
synchronised observation period ambient light is measured while the Hyperion LED is off and the
fluorescence signal of the fluorophore when the LED is on in order to cancel out the ambient light
effects.
If very high ambient light levels are encountered, e.g. bright sunlight, in shallow water where there is a
light coloured \ reflective bottom, the receiver may become saturated and return negative number
results. If this happens some form of shading will be required and the sensor not mounted so it
points directly at the bottom.

4.1. Setting the Gain

The Hyperion is set to the default range, for its specific analyte, before leaving Valeport.
The default range for any analyte w ill be its low range and, therefore, the instrument w ill be set to
maximum sensitively and gain. This w ill allow the measurement of low concentrations of the analyte.
Within this range there w ill be a linear response over 3 orders of magnitude
For Example:
in the case of Chlorophyll the default range is: 0.025 µg/l (MDL) to 25.0 µg/l (FSD)
In the case of Fluorescein the default range is: 0.01 ppb (MDL) to 25 ppb (FSD)
If high fluorophore concentrations are encountered, the range should be set to the non default
setting to allow a linear response over a far wider range.
The gain can be set as part of the setup wizard in DataLog x2:
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Data Acquisition
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