Vaisala HM44 - Manual (Page 40)

User's Guide _______________________________________________________________________
_________________________________________________________________________________ 38
lower point calibration. A message similar to the following appears with the first line
blinking:
RH
set
%
The blinking number indicates the value of the higher humidity reference stored in the HMI41
memory. Insert the probe to the higher reference humidity. Check the salt chamber
temperature, read the closest humidity value in the calibration table and adjust the display
with buttons
▲ and ▼ to correspond to the value given in the table. For example, if the
temperature in the calibrator's NaCl salt chamber is 20.5 °C, adjust the value to 97.6 %RH:
RH
set
%
Press ENTER and the HMI41 indicator shows the value that the probe is currently measuring.
Wait for the reading to stabilize (about 30 minutes) and press ENTER. Now the higher
humidity value is corrected to the given high reference. Press ENTER again to conclude the
calibration. If the calibration has been successful, the following message appears:
The correction data has now been calculated and stored in the HMI41 memory. The HMI41
returns automatically to the basic display and it can be turned off. If the correction data differs
from the factory settings, an arrow in the upper right-hand corner is displayed showing that
the correction has taken place.
If the message “cal pass” does not appear (instead, some other text may appear, e.g. “too
close”, “err offset” or “err gain”), the correction has not been stored in the memory. The error
may be due to an incorrect reference value or to measured values that are out of the range.