Vaisala HMT330 - Manual (Page 107)

Chapter 4 _________________________________________________________________ Operation
VAISALA _______________________________________________________________________ 105
Table 28 Conversion Factors for Pressure Units
From To: hPa
mbar 1
Pa N/m2 0.01
mmHg torr 1.333224
inHg 33.86388
mmH
2
O 0.09806650
inH
2
O 2.490889
atm 1013.25
at 980.665
bar 1000
psia
1)
68.94757
1) psia = psi absolute.
For example, 29.9213 inHg = 29.9213 × 33.86388 = 1013.25 hPa.
Limit RH Output Range
Use the serial line command RHLIMIT if you want to strictly limit the
allowed value of the relative humidity (RH) quantity to range 0 ... 100%.
The limit is implemented on all outputs and the display. Other quantities
are not affected, only RH. Note that seeing values above 100 %RH is
useful for detecting condensation on the sensor, and possible
measurement drift in very high humidities. For this reason, Vaisala
recommends leaving this feature at the default setting (off).
RHLIMIT [ON/OFF]
where
ON = Allowed range of RH output is 0 ... 100 %.
OFF = Allowed range of RH output is -5 ... 110 % (default).
Example (view current setting):
>rhlimit ?
RH limit 0...100: OFF
>
Example (enable RH limit):
>rhlimit on
RH limit 0...100: ON
>