Campbell EE181, Инструкция по эксплуатации, Страница: 16 / 32

Model EE181 Temperature and Relative Humidity Probe
8
output scale is 0 to 1000 mV for the temperature range of –40 to 60 °C and 0 to
1000 mV for the relative humidity range of 0 to 100%.
VoltSE (Dest, Reps, Range, SEChan, MeasOff, SettlingTime,
Integ/FNotch, Mult, Offset)
Variations:
•
Temperature reported as °C
—
set Mult to 0.1 and Offset to -40
• Temperature reported as °F
—
set Mult to .18 and Offset to -40
•
Humidity reported as a percent – set Mult to 0.1 and Offset to 0
• Humidity reported as a fraction – set Mult to 0.001 and Offset to 0
When the probe is connected to a CS110 Electric Field Meter, the
probe is measured by the CS110’s internal CR1000 datalogger
module using VoltSE() instructions. Relative humidity and
temperature signals are measured on single-ended channels 1 and
2, respectively. 250 µs integration should be used in the VoltSE()
instructions.
7.3 Field Installation
Sensors should be located over an open, level area at least 9 m (EPA) in
diameter. The surface should be covered by short grass or the natural earth
surface where grass does not grow. Sensors should be located at a distance of
at least four times the height of any nearby obstruction and at least 30 m (EPA)
from large, paved areas. Sensors should be protected from thermal radiation
and adequately ventilated. Protect the filter at the top of the sensor from
exposure to liquid water. The hydrophobic nature of the filter repels light rain,
but driving rain can force itself into the pore structure of the filter and take time
to dry out.
Standard measurement heights:
1.5 m (AASC 1985)
1.25 to 2.0 m (WMO 2008)
2.0 m (EPA 2008)
See Section 10 , Attributions and References
(p. 13)
, for a list of references that
discuss temperature and relative humidity sensors.
When used in the field, the EE181 must be housed in a radiation shield such as
the RAD10E naturally aspirated shields.
The white color of these shields reflects solar radiation, and the louvered
construction allows air to pass freely through, thereby keeping the probe at or
near ambient temperature. The RAD10E uses a double-louvered design that
offers improved sensor protection from insect intrusion and driving rain and
snow. In addition, the RAD10E shield has lower self-heating in bright sunlight
combined with higher temperatures (> 24 °C (75 °F)) and low wind speeds (< 2
m/s (4.5 mph)), giving a better measurement.
NOTE