Campbell Scientific CS106 Barometer - Manual (Page 21)

CS106 Barometric Pressure Sensor
8.5 Correcting Pressure to Sea Level
The weather service, most airports, radio stations, and television stations adjust
the atmospheric pressure to a common reference (sea level). Equation 3 can be
used to find the difference in pressure between the sea level and the site. That
value (dP) is then added to the offset (500 mb in our example programs) in the
measurement instruction. U. S. Standard Atmosphere and dry air were
assumed when Equation 3 was derived (Wallace, J. M. and P. V. Hobbes,
1977: Atmospheric Science: An Introductory Survey, Academic Press,
pp. 59-61).
dP
E
= − −














1013 25 1 1
44307 69231
5.25328
.
.
(3)
The value dP is in millibars and the site elevation, E, is in meters. Add dP
value to the offset in the measurement instruction.
Use Equation 4 to convert feet to meters.
E m
E ft
ft m
( )
( )
.
=
3 281
(4)
The corrections involved can be significant: e.g., at 1000 mb and 20 °C,
barometric pressure will decrease by 1.1 mb for every 10 meter increase in
altitude.
9. Maintenance and Calibration
Since the sensor is semi-sealed, minimum maintenance is required:
1. Visually inspect the cable connection to ensure it is clean and dry.
2. Visually inspect the casing for damage.
3. Ensure that the pneumatic connection and pipe are secure and undamaged.
The external case can be cleaned with a damp, lint-free cloth and a mild
detergent solution.
Vaisala recommends recalibration every two years under normal use. In areas
where a lot of contaminants are present, recalibration every year is
recommended.
Contact Campbell Scientific, Inc. ((435) 227-9000) for an RMA number before
returning the sensor for recalibration.
Should you lose the five terminal connector (pn 16004), the replacement part
can be purchased from Campbell Scientific, Inc. Contact Campbell Scientific,
Inc. to purchase the part.
The CS106 is sensitive to static when the backplate is
removed. To avoid damage, take adequate anti-static
measures when handling.
CAUTION
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