User Guide

11
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 at-
tention 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 5.78 mA, representing the
theoretical chamber value of 11.1% 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 C
l
11. 1 %
N
a C
l
75.4%
CALIBRATION KIT
Li Cl
11.1%
Na Cl
75.4%