Wet/Dry Bulb Transducers
The HT-WD-420 provides inexpensive yet very accurate rH measurements over a wide temperature range. It connects to two RTD sensors in a wet/dry bulb arrangement and outputs 4-20mA proportional to 0-100% rH. The board may be used for rH measurements in industrial environment where high temperatures and harsh environment preclude the use of other instruments. It may also be used for enthalpy control and in most accurate climate monitoring applications.
The HT-WD-420 is microprocessor based using the signal from two 3-wire RTD sensors (wet bulb and dry bulb) to calculate the relative humidity value. The microprocessor utilizes a scientific rH calculation algorithm that produces very accurate data over a wide temperature range.
(This algorithm is a refined version of ASHRAE equations used originally for the creation of Psychrometric Charts).