Vaisala HMT330 - Manual (Page 42)

User's Guide _______________________________________________________________________
40 ___________________________________________________________________ M210566EN-K
Probe Mounting
In humidity measurement and especially in calibration it is essential that
temperature of the probe and measuring environment is the same. Even a
small difference in temperature between the environment and the probe
causes an error. As the curve below shows, if the temperature is +20 °C
and the relative humidity 100 %RH, a difference of ±1 °C between the
environment and the probe causes an error of ±6 %RH.
The graph below illustrates the measurement error at 100 %RH when the
difference between the ambient and sensor temperature is 1 °C.
0507-023
Figure 22 Measurement Error at 100 %RH