Stable RH and temperature data outdoors depends on correct sensor exposure and clean signal transmission. HD9009 transmitters are microprocessor-based RH and temperature devices designed for meteorological and environmental monitoring, with standard voltage outputs that integrate easily into data loggers and acquisition systems.
The humidity sensor uses a hygroscopic polymer capacitive element for 0...100% RH measurement, while temperature is measured with a Pt100 element. Outputs are designed to increase linearly as humidity and temperature rise. Standard scaling sets 0...100% RH to 0...1 Vdc and -40...+80 °C to 0...1 Vdc, and the temperature output can be reprogrammed within the -40...+80 °C range with a minimum span of 25 °C.
Installation guidance supports reliable measurement in the field. The transmitter position does not affect accuracy, but the sensor is typically installed facing downwards where possible to reduce dust on the protection filter. For weather station use, the HD9007 multiple radiation shields (HD9007A-1 and HD9007A-2) can be used to protect sensors from solar radiation, rain and wind, and proper cable routing with shielded cables is recommended in noisy environments.
Measures relative humidity (0...100% RH) and temperature (-40...+80 °C) using capacitive RH and Pt100 sensors.
Standard output is 0% RH = 0.00 Vdc, 100% RH = 1.00 Vdc and -40 °C = 0.00 Vdc, +80 °C = 1.00 Vdc.
Humidity can be recalibrated at fixed points 75.4% RH and 33% RH while keeping the 0...100% RH range fixed.
Temperature output can be programmed with a Pt100 simulator or precision resistances, with LED guidance during setup.
Power supply is 5...35 Vdc and minimum input resistance for voltage outputs is 10 kΩ.
Probe dimensions are Ø 26 x 185 mm with IP65 protection.
