Casella CEL Nomad portable weather station - Manual (Page 45)

6.5.1 Global Solar Radiation Sensor Specification
Part number: 187010B
Spectral range: 0.4 to 1.1
µm
Range: 0 - 2000 W/m²
Sensitivity: Typically 100 µV/W/m²
Response time: <1 s
Cosine response: Typically <10% from normal to 80° of normal
Operating temp: -40°C to +80°C
Supply voltage: Passive device, no supply is required
Output calibration: Typically 100 µV/W/m², supplied with
individual calibration details
6.5.2 Sunshine Duration
The internal logger can determine daily Sunshine hour values. The accumulated
total is determined based upon the time during which the solarimeter has been
exposed to a radiation level exceeding a threshold of 200W/m².
6.6 Barometric Pressure Sensor
The new Casella barometer is mounted on a
circuit board in the data logger, which itself
is inside the environmental case. A 1 mm
ventilation hole in the case ensures the
internal pressure remains at ambient.
A monolithic silicon transducer
senses pressure by means of a silicon
diaphragm into which a “bridge” of piezo
resistors have been defused.
The silicon crystal, which
constitutes the diaphragm, being a perfect
device does not suffer from hysteresis. The
high signal level obtained is further
conditioned to give an exceptional degree of
accuracy, repeatability and linearity.
The pressure transducer is
temperature stabilised at 60°C to minimise
temperature effects on the overall accuracy.
6.6.1 Barometric Pressure Sensor Specification
Part number: 183014B
Transducer: The pressure sensor is temperature stabilised
at 60
o
C
Range: 800 to 1100 hPa (mB)
Operating temp: -40°C to + 85°C
Accuracy: <1 hPa (mB)
Temperature drift: Typically <0.15 mB/°C
Supply voltage: 9 - 12 V nominal
Power consumption: Approx. 10 mA at 12 V
6.7 Rainfall Sensor
The tipping bucket raingauge should be positioned horizontally at least twice the
height of any obstruction (weather station tripod) away from the obstruction.
Connect it to the 4-pin socket via the 9 m cable supplied.
The tipping bucket is a well proven method of monitoring rainfall whith
a divided bucket assembly mounted on pivots.
Standard Sensors
The pressure sensor board
Figure 15: Barometric pressure
Page 45 of 68
NOMAD Portable Weather Station
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