7
6
TAKING MEASUREMENTS
• For a rapid response, expose the end of the
humidity detector to an air current moving at
more than 0.5 m/second.
In absence of air movement, the response
can be speeded up by shaking the probe.
• If condensed drops form upon the surface of
the humidity sensors, turn the instrument off
and wait until this undesired water has com-
pletely evaporated. To speed up the evapora-
tion process, expose the humidity sensors to
an air current.
• If the meter is used in dusty surroundings, the
filter must be kept on at all time.
Calibration procedure
• Bring the calibration kit to a temperature of
approximately 20 ºC.
• Remove the plug from the chamber contain-
ing the LiCl solution and insert the probe.
• Remove the adhesive sticker which covers
the calibration trimmer access holes.
• Wait for the reading to stabilize (this will take
a few hours) and then turn the "Low humidity
trimmer" (the one nearest to the probe con-
nection cable) until the value of 11.1% RH will
be displayed on the LCD.
• Remove the probe and tightly seal the cham-
ber containing the LiCl solution.
• Remove the plug from the second chamber
and insert the probe.
• Wait for the reading to stabilize and then note
the displayed value.
• By using the Calibration Table (pages 8-9),
find the displayed readout value on column
"A" and the corresponding RH value of col-
umn "B", to which the meter has to be brought
by acting on the "High humidity trimmer".
• Adjust the "High humidity trimmer" (the one
opposed to the connection cable) until the
required value is displayed on the LCD.
• Finally adjust the "Low humidity trimmer" until
the value of 75.4% RH will be displayed on the
LCD.
The HI 8064 thermohygrometer is factory cali-
brated and therefore usually it requires no fur-
ther intervention by the user.
If recalibration is desired, proceed as follows:
• Remove the adhesive sticker which covers the
calibration trimmer access holes.
• Insert the probe into a recipient in which air
heated at a temperature of 50 ºC has been
forced to circulate.
• Insert a thermometer with an accuracy of 0.1
ºC into the same recipient.
• Read the temperature value on the thermom-
eter.
• Adjust the temperature calibration trimmer
(the central trimmer) until the measured tem-
perature value is displayed on the LCD.
TEMPERATURE CALIBRATION