humimeter RH5 & RH5.1 Operating Manual
Page 28
7.
Product types
Product type
Unit
Measuring range
Relative humidity
% r.h.
0 to 100 %
Dew Point
°C
°F
-55 °C to +60 °C
-67 °F to 140 °F
7.1
Definition of relative humidity and dew point
Relative humidity
Indicates the relationship between the current water vapour pressure and the maxi-
mum possible, the so-called saturation vapour pressure.
The relative humidity shows the degree the air is saturated with water vapour.
Examples:
50% relative humidity: At the current temperature and pressure, the air is half satura-
ted with water vapour. 100% relative humidity means that the air is totally saturated
with water vapour. If the air has more than 100% humidity, the excessive humidity
would condense or precipitate as mist.
Dew Point
The dew point is the temperature to which the air that is not completely saturated with
water vapour must be cooled so that it is completely saturated. When a room with the
current relative humidity cools down to the dew point temperature, the water vapour
begins to condense.
7.2
Application range
Within the normal application range (normal range) the accuracy of the device is as
indicated. A long-term application beyond the normal application range (max. range),
particularly at an air humidity of more than 80%, can lead to higher measuring errors
(+3 % after 60 hours). Back in the normal application range, the sensor will return to
the indicated accuracy automatically.