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9
Calibration of Contactless Sensors
For preparing a setup with contactless oxygen sensors, please refer
to the chapters 5.4-5.6.
9.1
Calibration Procedure
In general, the calibration procedure for contactless sensors (e.g.
sensor spots, flow-through cells, respiration vials) is the same as
for fiber-based oxygen sensors as described in the chapters 7 and
8. However, if a 1-point or a 2-point calibration should be
performed, the calibration standards have to be filled directly into
the vessel in which a sensor spot is glued into, into the tubing of
the flow-through cell, or into the respiration vial.
If “Ambient Air” is used for the air calibration standard (see chapter
8.1.1), a good air circulation of the ambient air into the
dry
setup is
important, ensuring that the relative humidity within the setup is
identical to the relative humidity outside the setup (experienced by
the
FireStingO2
). However, for typical applications around room
temperature and below, a falsely determined relative humidity
gives a maximum relative error of 1% for the air calibration (refer
also to chapter 8.1). So, if this precision is sufficient, “Ambient Air”
should be the preferred option for the air calibration standard.
For precision applications, where it is not possible to ensure a dry
setup for the calibration procedure, the alternative air calibration
standards “Water-Vapor Saturated Air” (see also chapter 8.1.2) or
“Air Saturated Water” (see also chapter 8.1.3) should be preferred.
In the first case some part of the inner volume of the setup can be
filled with e.g. wet cotton wool ensuring 100%RH around the
oxygen sensor position. In the latter case, the inner volume of the
setup is simply filled with air saturated water prepared as described
in chapter 8.1.3. Ensure that the oxygen sensor is
completely
covered with the air saturated water!
