|
Operation
The rotor spindle turns a multi-slotted disc, interrupting the beam from a light-emitting diode. The output is obtained by amplification of the signal from an opto-electronic sensor in the path of the light beam. All rotors are tested by comparison with a N.P.L. calibrated rotor, and individual calibration data are provided. The small size and light weight of the FM2000 series anemometers together with the patented gravity-sensitive fastener for the rotor facilitate use in portable appli-cations, and although built to withstand hurricane force winds, the balanced 3-cup rotor also offers unsurpassed sensitivity and accuracy at low wind speeds.The three versions offered provide for a range of resolutions according to type of application, two of which allow direct readout of wind speed in Knots or m/s using standard electronic counter/timers.
Construction
From anodised aluminium alloy, stainless steels, and weather resisting plastics for all exposed parts. The bearings (stainless steel shaft running in two precision corrosion-resistant ball-races) are protected from the entry of moisture droplets and dust resulting in an instrument suitable for permanent exposure to the weather including marine environments. A touching shaft-seal can be fitted for extra protection as an alternative to the standard non-contact seal, with a small increase in threshold speed.The wide range of operating temperatures allows use at any latitude, an anti-icing heater can be fitted if required.
FM 2000 Series Pulse Output Anemometer
Performance
Maximum speed : 75m/sec
Threshold : 0.15 m/s (0.5 m/s with touching shaft seal).
Linearity : 2%
Accuracy : 1% + 0.05 m/s
Distance constant : 5m (std. 3-cup rotor; fast response rotor also available).
Electrical
Supply voltage : 10 to 30 volts DC.
Supply current : 45 mA (max.) at 12 volts.
Output voltage : +O.1 to +12V square wave with 1 2V supply.
Output resistance : less than 100 Ohms (0V o/p) 1K Ohm (1 2V o/p level)
Temperature range : -50 to +55°C
Connections : 4-wire system (or 3-wire with short lines).
Output - Pulse rate and Revolutions
Type Nominal Pulse Rate (+/- 2%) Pulses / Wind Run Resolution (cm) Duty Cycle
FM 2000 0.8Hz per m/s 1 pulse per 1.25m 125 50% +/- 5%
FM 2001 10Hz per Knot 10 pulses per 1.69ft. 5.15 50% +/- 20%
FM 2002 10Hz per m/s 10 pulses per metre 10 50% +/- 10%
Mechanical
Fixing : ¼ UNC internal thread
Net Weight : 350g with 3m cable
Packed weight : 700g
Packed dimensions : 25 x 16 x 16cm
Ordering Information:
FM 2000 Pulse Output Anemometer - Output : 1.25m wind run per revolution
FM 2001 Pulse Output Anemometer - Output : Knots
FM 2002 Pulse Output Anemometer - Output : Metres per second
|
Typical array of sensors for the Fairmount AWS for the measurement of:
Temperature
Relative Humidity
Solar Radiation
Rain Gauge (tipping bucket type)
Wind Speed
Wind Direction
|
|
Typical array of sensors for the Fairmount AWS for the measurement of:
Temperature
Relative Humidity
Solar Radiation
Rain Gauge (tipping bucket type)
Wind Speed
Wind Direction
|
This is a typical Fairmount AWS being prepared for installation and testing
|
|
|
