Vaisala HMM100 - Manual (Page 38)

User's Guide _______________________________________________________________________
36 ___________________________________________________________________ M211024EN-C
Calibrate Humidity Measurement
Use the CRH command to perform a one-point or two-point correction to
the humidity measurement of the module. This command changes the
offset and gain of the measured capacitance, and therefore affects
humidity measurement over the entire temperature range. Take care
when making this adjustment, and ensure you make a note of the existing
values before adjusting them.
CRH
When performing a one-point calibration, you need to place the probe in
a single humidity reference with RH < 50%. Run the command and enter
the exact RH of the reference after the measurement has stabilized. Exit
the command by pressing the ESC key before proceeding to the second
point (see example 1 below).
For two-point calibration, the first point requires a RH < 50% humidity
reference, the second point must be RH > 50%. There must also be at
least 30 percentage points of difference between the references.
Example: one-point calibration
>crh
RH: 11.29915720 Ref1 ? 11.3
Press any key when ready
>
Example: two-point calibration
>crh
RH: 11.29915720 Ref1 ? 11.3
Press any key when ready
RH: 75.04306440 Ref2 ? 75
OK
>