Weather Station

Technical Specifications

Wind speed Sensor	3 Cup Anemometer.
Sensing	3 cup assembly mounted on friction free shaft and coupled to a chopper
Starting threshold	0.3 meters/sec
Range	0 to 65 meters/sec
Distance constant	2.5 Meters
Output	TTL pulses output proportional to wind Built in line driver to drive long cable > 50 ohms loop resistance.
Accuracy	Better than 0.5 m/s up to 10 m/s + 2% FSD
Diameter of cup	50 mm.
Diameter of cup assembly	165 mm.

Construction of sensor body : Brass housing and stainless steel shaft .

Principle of Operation
Anemometer is a fast response, low threshold opto electronic anemometer. When rotated by wind, a chopper on the anemometer shaft interrupts an infra red light source , generating pulses from a photo transistor. The signal is amplified and fed through a line driver . The frequency is proportional to wind speed. The anemometer is provided with a 3 pin connector for easy replacement and comes with 10 meters of shielded cable.

For operation at low temperature the sensor can be supplied with a built in heater The Anemometer can be supplied with a 20W 24 V DC built in heater for operation at low temperatures.

Note : These specifications are likely to change without notice.

Wind Direction Sensor Model -DWD 8601

Wind Direction Sensor	Wind Vane.
Sensing	Vane coupled to linear endless potentiometer.
Starting threshold	Better than 0.5 meters/sec.
Range	0 to 357 degrees (3 degrees electrical gap in the Potentiometer
Output	0 to 5 kilo-ohm resistance ( 0 to 357 degrees).
Resolution	1 degree.
Accuracy	+/ 3 degrees.
Operating Temperature	40 to + 60 degree Celsius

Construction of sensor body : Brass housing, stainless steel shaft and aluminum vane

Principle of Operation
DWD 8601 wind vane is a counter balanced, low threshold wind vane. A Linear, wire wound endless potentiometer is coupled to the vane by an SS shaft. As the vane turns, it rotates a stainless steel shaft which is coupled to the potentiometer. This potentiometer has excellent linearity, very low starting torque.

The north of the wind vane is marked on its body. This line is to be aligned with actual North with the help of prismatic compass, at the time of installation. Sensor gives minimum resistance at North (i.e., 0 degree approximately 20 ohms ). The resistance output linearly proportional to the position of the wind vane

Temperature and Humidity Combined Sensor

Model No. DLTH 8702

Principle of Operation
The sensor used for measurement is an RTD ( PT 100). Here the resistance of the element varies with temperature (increases with temperature), approximately 0.39 ohms/degree Celsius. Output is 0 to 1 Volt corresponding to -40 to 60 deg C

Humidity

Principle of Operation
Humidity sensor features an improved design to provide highly accurate and rapid measurements. The humidity sensor is a thin film capacitor element. A dielectric polymer absorbs water molecules from the air through a thin metal electrode and this causes a capacitance change proportional to humidity.

Rainfall Sensor : Model No.DTR 8104

Principle of Operation
It uses a tipping bucket mechanism to produce a contact closure every time it receives a predetermined quantity of rainfall. The body and funnel are made of FRP (Fiber glass Reinforced Plastic), rim is made of gun metal. All parts having contact with water are made of stainless steel. Each tip of the bucket produces an on-off output when the magnet passes over the reed switch.