HD9008TRR Transmitters for humidity and temperature

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HD9008TRR Transmitters for humidity and temperature

Measuring range humidity 0÷100% RH
Temperature measurement range -40°C ÷ +80°C
Outputs 4÷20mA - 0÷mA - 0 10 - 0÷5Vdc - 1÷5Vdc
7÷30Vdc power supply
Degree of protection IP54
Hd9008trr transmitters for humidity and temperature with protection ring against solar radiation
The HD9008TRR is a passive transmitter with a 4…20mA output and 7…30Vdc power supply.
Sensors are mounted at the end of a plastic tube: a capacitive humidity sensor and a Platinum temperature sensor (100Ω @0°C).
The instrument can be reprogrammed by means of a key, and no jumper or potentiometer actions are required. The humidity input can be recalibrated by using two saturated solutions: the first one at 75%, the second one at 33%; the 0%RH…100%RH relative humidity range is fixed, 4mA (or 0Vdc) correspond to 0%RH, 20mA (or 1Vdc) equal 100%RH.

Temperature standard configuration is –40…+80°C for the HD9008TR for the HD9009TR, corresponding to 4…20mA and 0…1Vdc, respectively.
The user can configure the temperature output in ranges different from the standard one by means of a Pt100 simulator or of a set of fixed resistances, provided that it is included in the -40°C…+80°C range with a minimum amplitude of 25°C.
Two leds give alarm indications (temperature exceeding set range, sensor breakage or short-circuit) and help the operator when programming.
An out-of-standard temperature operating range can be requested when placing the order.

N.B: probes work in the -40°C…+80°C temperature range. Outside this range data are not correct. Electronic is designed to operate in this range.

The humidity sensor is a condenser which dielectric is made up by an hygroscopic polymer. As water dielectric constant is approximately 80, you’ll get a strong change in capacity as the humidity content of this polymer changes.
The advantages of this kind of sensor are: good linearity, insensitivity to temperature changes, fast response time and long-lasting life.
The sensor temporarily looses its accuracy if some condensation develops on its surface (the transmitted value is higher than the real one because of an increase in effective capacity).
The temperature sensor is a Platinum resistance thermometer (100Ω @0°C).
The Pt100 resistance variation is transformed into a current or voltage signal, linear to temperature.

The electronic circuit design provides the signal to increase linearly as humidity and temperature raise. In presence of cables transmitting high currents or machines causing electromagnetic noises, the transmitter connection cables have to be placed in a separate raceway, or far from them, to prevent these noises.
It is recommended to use a shielded cable for the connections of instruments having a voltage output (HD9009TR).