Vaisala HMP240 - Manual (Page 65)

HMP240 series
M210300en User's Guide
63
8.2 Temperature (with additional T sensor head)
Measurement range -40...+180 °C
Typical accuracy at +20
°
C (+68
°
F) ±0.1 °C
Typical temperature dependence of
electronics
0.005 °C/°C
Temperature sensor Pt 100 RTD DIN IEC 751,
class 1/4 B
8.3 Calculated variables
Without the additional temperature head only dewpoint temperature and
mixing ratio are available.
Typical ranges
relative humidity 0...100 %RH
dewpoint difference 0...+50
°
C
mixing ratio 0...500 g/kg dry air
absolute humidity 0...600 g/m 3
wet bulb temperature 0...+100 °C
Response time (90 %) at +20 °C in
still air (with sintered filter)
15 s
Accuracies of the calculated quantities depend on the accuracies of the meas-
ured quantities: relative humidity and temperature. In the dewpoint accuracy
graph and accuracy tables for x, a and Tw the accuracies of relative humidity
and temperature are assumed to be ±(0.5 + 2.5 % of the reading) %RH for
humidity and 0.1
°
C for temperature (at 25
°
C). Note that the user can select
whether the HMP240 calculates the frostpoint (default) or the dewpoint when
the dewpoint is < 0
°
C. In addition, the HMP240 also calculates the dewpoint
difference, i.e. the difference between the ambient temperature and the
dewpoint ( = dT).
8.3.1 Relative humidity (with additional T sensor head)
Accuracy (including nonlinearity and repeatability)
maximum achievable accuracy when calibrated against high quality,
certified humidity standards:
+(0.5 + 2.5 % of the reading) % RH
for example, accuracy at:
0 % RH +0.5 % RH
60 % RH +2.0 % RH
Response time (90 %) at +20 °C in
still air (with sintered filter)
15 s