4-20mA Humidity Temperature Pressure Sensor HVAC Temperature & Humidity Transmitter Description KTH500 is a relative humidity transmitter with temperature output installed in air ventilation duct. In addition to these measured values, KTH500 calculates various parameters such as dew point, mixing ratio, enthalpy and absolute humidity. Illuminated display ensures easy readability also from a distance. KTH500 has a screwless lid and an easily adjustable mounting flange that