The HMD60/70 duct-mounted humidity and temperature transmitters are designed for air conditioning applications where accurate and stable measurement of humidity and temperature is required, the company states. They incorporate the Humicap® sensor, which, according to the manufacturer, has excellent accuracy, long-term stability, negligible hysteresis, and resistance to dust and most chemicals. The units are available in two models: One is for humidity measurement only and the other is for humidity and temperature measurement. True two-wire and three-wire models are available, states the company. The transmitters measure humidity ranging from 0 percent to 100 percent rh, with a typical accuracy of ±2 percent rh.
Vaisala Inc., 100 Commerce Way, Woburn, MA 01801-1068; 781-933-4500; 781-933-8029 (fax); www.vaisala.com.