Vaisala HMP42 - Manual (Page 22)

HMI41 AND HMP42
Operating Manual
M210317EN-A
18
The correction data has now been calculated and stored in the HMI41 memory.
The HMI41 returns automatically to the selection of display units, and can be
turned off. When the indicator is used as a standard indicator and the
correction data differs from the factory settings, an arrow in the upper
righthand corner is displayed:
RH
T °C
%
If the message “cal pass” does not appear (instead, some other text may
appear, e.g. “too close”, “err offst” 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.
5.3.2 Two point humidity calibration
In two point humidity calibration, two accurate references (e.g. the HMK15
Calibrator) are needed. Leave the reference instrument and the probe at the
calibration site for at least 30 minutes so that the probe temperature stabilizes
to the room temperature.
Start the calibration by inserting the probe to the lower reference humidity. In
setup mode press ENTER repeatedly until the following is displayed:
set
Then press MODE three times, and the following appears:
RH
set
Press ENTER to activate the two point humidity calibration mode. A message
similar to the following appears with the first line blinking:
RH
set
%
Lo