Tools – ARH4 Relative Humidity Head

The Fieldpiece model ARH4 measures both relative humidity and ambient air temperature. The ARH4 also calculates dew point and wet bulb temperatures. The head converts RH%, ambient temperature, dew point temperature, and wet bulb temperature to a voltage at a rate of 1 RH% or degree to 1mVDC. Set the meter to mVDC to display RH% or temperature directly. The ARH4 snaps directly onto the Fieldpiece HS series DMM. For other meters, use Fieldpiece ADLS2 test leads or AHDL1 handle adapter. To get an accurate reading, allow enough time for the sensors to come to equilibrium. The bigger the change, the longer the time the ARH4 may need to calibrate to ambient conditions. Usually not more than a couple minutes for even large changes.