i) Gently open the cover of the 33% RH
calibration salt bottle and carefully
insert the probe into the bottle.
The probe will hit a stopper when
it is fully inserted.
ii) Press RST twice. The meter will beep
each time the key is pressed. Do not
press any other keys! The screen dis-
plays a percent humidity and “MIN”.
Low humidity calibration begins
automatically and takes 20 to 45
minutes to complete.
See figure
iii) When low point calibration is com-
plete, the meter will beep once and
display “SA”, “MIN”, and “MAX”.
See figure
5.
Calibrate the high humidity point:
i) Gently open the cover of the
75% RH calibration salt bottle and
carefully insert the probe into the
bottle.
The probe will hit a stopper
when it is fully inserted.
ii) Press NEXT. The screen displays
a percent humidity and “MAX”.
High humidity calibration begins
automatically and takes 20 to 45
minutes to complete.
See figure
iii) When high point calibration is
complete, the meter beeps once
and displays “SA” briefly. Meter
automatically returns to measure-
ment mode.
Relative Humidity Calibration
10
11
MIN
%RH
4.2
B
C
MIN
MAX
D
Before calibration
Check the relative humidity calibration of your meter every 30 days or more
often if you frequently measure extreme humidity conditions. To do this, place
the probe in each calibration salt bottle and check the measured value against
the reference value.
• If the measured value does not equal the reference value, recalibration
may be necessary (if the difference between the values does not meet your
accuracy requirements).
• If the values are only slightly different and you do not require the highest
possible accuracy, then calibration is not necessary.
Two-point relative humidity calibration is necessary to maintain the accuracy
of the meter throughout its full range. Relative humidity calibration takes
20 to 45 minutes per point.
IMPORTANT:
You will not get good results if your calibration temperature
varies more than ±0.5°F in five minutes. If this happens, the meter automatical-
ly extends the calibration time, so if the temperature is very unstable the
calibration might never be complete.
To prevent this, thermally isolate the calibration salt bottle and probe, or place
them in a temperature-controlled environment, such as the carrying case. Keep
away from sunlight, electronic equipment, drafts, heating ducts, and all other
causes of temperature variation.
Automatic Humidity calibration:
1.
Place the meter, probe, and calibration
salt bottles in a place where the
temperature will remain constant
(< ±0.5°F) for 40 to 90 minutes.
2.
Press OFF.
3.
Press ON and PRG simultaneously
and hold until the screen displays
“CAL”.
Release the keys. The screen
displays the temperature offset value.
See figure
4.
Calibrate the low humidity point:
CAUTION:
Be careful when inserting
the sensor probe into the calibration salt
bottles. Rough movement may damage
the bottle.
MAX
%RH
E
E
B
D
C
Notes on automatic humidity calibration
While the meter is calibrating, do not press any key. If you do, calibration will stop and
you will have to start the process over again. If you need to discontinue the calibration
process, press RST twice and the meter will return to the measurement mode.
