DeFelsko POSITECTOR DPM Full Manual page 7

For surface temperature measurement on steel over an
extended of time, consider using the optional Magnetic Surface
Temperature probe (pg. 7).
T T
s - d - The surface minus dew point temperature 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 protective coatings are
applied.
Does not apply to DPM-D models
NOTE:
T
w - (Advanced models only) The wet bulb temperature is the
temperature of adiabatic saturation. This is the temperature
indicated by a moistened thermometer bulb exposed to air flow.
The wet bulb temperature is calculated from Ta and RH using an
air pressure of 1.0 atmospheres (1013mbar). It approximates the
temperature indicated by a moistened thermometer bulb exposed
to airflow. Variations of Tw at other pressures could be greater than
±1°C (±2°F).
V - Wind velocity is measured with a hot-wire anemometer located
inside the aluminum housing (DPM-A models only)
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