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9
CHECKING THE RH CALIBRATION
•
Bring the calibration kit to a temperature
of approximately 20°C.
•
Remove the sintered
cap from the probe
of HI 8666.
•
Connect the unit to a 12 to 24VDC power
supply and hook up a multimeter (range
of 20mA) in series with the circuit.
•
Remove the cap from the
"RH 11.1%" chamber con-
taining the LiCl solution and
insert the HI 8666 paying
attention not to dip it into
the liquid.
•
Wait for the measurement
to stabilize (this takes ap-
proximately 4 hours).
•
Look at the multimeter display: the read-
ing should be 4.00 mA, representing the
theoretical chamber value of 0.0% RH.
All RH to mA conversions can be made
with the tables provided (see page 12).
•
Remove the HI 8666 from the chamber
and tightly seal the chamber containing
the LiCl solution.
•
Remove the cap from the
"RH 75.4%" chamber con-
taining the NaCl solution
and insert the HI 8666.
12
3
6
9
4 h
CALIBRATION
KIT
Li Cl
11.1%
Na Cl
75.4%
mA
CALIBRATION KIT
Li Cl
11.1%
Na Cl
75.4%