DeFelsko PosiTector DPM v.2.0 - Manual (Page 3)

3
Operation Overview Operation Overview
Upon power-up, the following 5 parameters are
displayed and updated automatically each second.
RH - The relative humidity sensor is located inside
the white plastic housing. The sensor may require a
longer period to stabilize in the event of extreme
humidity changes.
T a - The air temperature sensor is also located
inside the white plastic housing.
T s - A surface temperature thermocouple is located
on the tip of the silver probe. It is spring loaded and
designed to quickly self-align on a surface. Press it
against a surface and allow a few seconds for the
value to stabilize. Do not drag the sensor over the
surface. Wet the surface for a faster response.
For surface temperature measurement over
a long period of time, consider using the optional
Magnetic Surface Temperature kit (pg. 11).
T d - The dew point temperature is a function of air
temperature and relative humidity (see ISO 8502-4
Annex A). It is the temperature to which a volume of
air must be cooled in order to reach saturation.
- The delta value is the surface minus dew point
temperature ( T s - T d). This value is important in
judging the risk of condensation, or dew, forming on
a surface. For example, ISO 8502-4 recommends
that, unless otherwise agreed, the temperature of a
steel surface generally should be at least 3°C (5°F)
above the dew point when paints are applied.
The instrument may require a period of time
before the above climatic parameters stabilize. This
is most noticeable when the instrument is relocated
from one extreme environment to another (i.e. from
a warm location to a cold location). A period of up to
30 minutes should provide adequate time for
stabilization.
NOTE:
NOTE: