3 wind speed sensor, 4 wind direction sensor, Standard sensors – Casella CEL Nomad portable weather station User Manual
Page 43
Operating temperature: -25° to +80°C
6.2.3
General Specification
Part number:
187012B
Supply voltage:
8 to 24 V (supplied from environmental case)
Power consumption:
Typically 10 mA at 12 V
Output calibration
Temperature:
0 to 1 V for -40 to + 60°C
Humidity:
0 to 1 V for 0 to 100% RH
6.3
Wind Speed Sensor
The sensitive three cup anemometer is
mounted at one end of the sensor head
cross-arm. The rotational speed is monitored
using an infra-red light source, interrupter
and optical sensor that provides 20 pulses
from 0 to 5 V per revolution. This
non-contacting design can measure wind
speeds up to 75 m/sec.
The instrument has an anodised
aluminium alloy outer case that offers a
durable, all-weather construction suitable for
installation in harsh environments.
An output from this sensor is led to
a terminal box on the sensor cross arm, from
where a single sensor cable is taken to the
7-pin socket on the bottom panel of the environmental case.
6.3.1
Wind Speed Sensor Specification
Part number:
178031C
Sensor type:
Three cup anemometer
Transducer:
Optical interrupter
Maximum wind speed:
75 m/s
Starting velocity:
Typically 0.3 m/s
Distance constant:
Typically 3.5 m/s
Time constant:
Typically <0.5 s
Resolution:
7.84 cm
Non-linearity:
<±0.6 %
Accuracy:
±0.3 m/s below 3 m/s
±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
6.4
Wind Direction Sensor
The weather vane is mounted at the other end of the sensor head cross-arm
from the anemometer.
DO NOT loosen the fitting of the weather vane, as this carries a
guide mark “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
01057
Figure 12: Wind speed sensor
Standard Sensors
Page 43 of 68
NOMAD Portable Weather Station
Users Handbook