HMP155 measures relative humidity and air temperature. Humidity measurement on the sensor is based on the capacitive thin film polymer HUMICAP sensor. Temperature measurement is based on platinum resistance (Pt100) sensors. Both the humidity and temperature sensors are located at the tip of the probe, protected by a removable filter.
HMP155 is installed inside a radiation shield, which ensures proper ventilation while protecting the sensor from solar radiation and precipitation. The shield provides ventilation while blocking both direct and reflected solar radiation. The radiation shield is DTR13.