Campbell Scientific CS125 Present Weather Sensor - Manual (Page 48)

CS125 Present Weather Sensor
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18. Cleaning
The CS125 present weather sensor is a robust instrument that will provide years of
uninterrupted weather monitoring. Calibration of the instrument is carried out at
the factory and can be redone easily on site with the optional CS125 calibrator or
carried out by Campbell Scientific if required. Only general cleaning of the lenses
is required to keep the sensor working efficiently.
Cleaning of the CS125 will be required from time to time to ensure that the lenses
are free from contaminants. The frequency of required cleaning depends on the
exposure of the instrument to such contaminants. This will vary depending on the
site location. The CS125 is capable of self diagnosing dirty lenses and will
indicate in its output when the lenses are contaminated to such a degree that its
visibility measurements may be affected.
A lower level of contamination than is detected by the dirty window
alarms, can affect the visibility measurements. The sensor can be
configured to attempt to make a correction for contamination
although the accuracy of that correction depends on the `type of
dirt’.
We suggest 6 monthly intervals for locations not prone to contaminants and
monthly intervals for those prone to contamination (roadside or airport use). In
some cases more frequent cleaning may be required where there are high levels of
contaminants and high dependency on the instrument output.
If the lenses require cleaning, it is very important that only a
proper lens cloth or lens tissue be used. The use of
inappropriate materials to clean the lenses can permanently
damage or reduce the effectiveness of the lenses leading to
errors in measurement of precipitation and visibility.
It is advisable to use an air duster to blow any loose dust and dirt from the lenses
as a first step. Using a lint free lens cloth or lens tissue impregnated with a small
amount of isopropyl alcohol solvent clean the lens surface by dragging the cloth
across the lens surface being careful not to apply excessive pressure.
Excessive pressure may lead to some types of contaminant scratching the lens
surface. Over time such scratches can lead to reduced sensor accuracy.
Spiders webs and certain `fluffy’ seeds which get lodged in the
optical path can lead to the sensor permanently giving low readings
as they can emulate precipitation. Cleaning the contamination away
with a duster will return the sensor to normal operation.
If spiders are a persistent problem, using some carefully applied
insecticide can deter them.
NOTE
CAUTION
NOTE