Casella CEL Automatic weather station - Manual (Page 21)

±3% over 3 m/s
Output calibration: 12.75 Hz/m/s
Output: 20 pulses per revolution 0 to 5 V
Operating temp: -20°C to + 70°C
Stabilisation time: <1 sec from power on
Supply voltage: 6 - 28 V DC (supplied from environmental
case)
Power consumption: 3 mA
3.2.2 Wind Speed Sensor - Sensus Channel Configuration
Description Wind speed
Units m/s
Type Analog
Information Frequency
Reset on scan
Display Format ##.#
Polynomial 0, 0.07246
Enabled Yes
Logged Yes
Minimum Limit 0.0
Maximum Limit 100.0
3.3 Wind Direction Sensor
The weather vane is mounted at the other
end of the cross-arm from the anemometer.
DO NOT loosen the fitting of the
weather vane, as this carries a guide
mark two “dots” or an “N” that must
point north to orient the cross arm
correctly.
The wind vane is a small
lightweight GMR design that offers a rapid
response to changes in wind direction with
virtually friction free sensing. The analog
output changes from 0 to 1.8 V as the wind
direction changes from 0 to 359°, with no
dead-band at north.
The instrument has an anodised
aluminium alloy outer case that offers a durable all-weather construction suitable
for installation in harsh environments.
3.3.1 Wind Direction Sensor Specification
Part number: 178035C
Sensor type: Weather vane
Transducer: GMR (giant magneto resistive sensor) solid
state system with micro-controller
Maximum wind speed: 75 m/s
Resolution: 1°
Accuracy: <±2°
Aligning threshold: <0.8 m/s for a 10° offset
Damping ratio: 0.25
Distance constant: Typically 3.0 m
Standard Sensors
01058
Wind direction sensor
Page 21 of 34
Automatic Weather Station
Assembly & Commissioning Handbook