6.2 Auto Calibration (AutoCal)
The
AutoCal
facility uses the fact that each sensor is designed and
manufactured to give no further increase in response when it reaches its
maximum moisture level.
For example
a SDHmini with a full scale value of 0
°C dewpoint will read 0 °C dewpoint when exposed to a gas with this moisture
concentration and will continue to read 0 °C dewpoint as the moisture
concentration rises above 0 °C dewpoint.
The SDHmini can therefore be adjusted to read 0 °C
dewpoint on any gas with a moisture concentration
wetter than 0 °C dewpoint, ambient air for instance, thus
setting the span to match the original calibration.
Select
AutoCal
from the
Setup Menu
.
Extend the desiccant head noticing that the value of the
full scale moisture level has already been automatically
preselected as a target of 0 °C.
Press .
The SDHmini will display a moving bar until it assesses
that the sensor has stabilised (up to ten minutes).
The SDHmini will now display the full scale value of the
unit, either -20 °C or 0 °C depending on the sensor range.
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