6.5 Programming 9
6.5.1 CS110() instruction 9
6.5.2 CS110Shutter instruction 10
6.5.3 Internal relative humidity sensor programming 10
6.5.4 Sensor programming 10
6.1 Site selection
Many factors can distort and/or change the electric field at a given sight. Select an appropriate
site for the system, far from tall buildings, tall vegetation, and sharp, metal points.
Vegetation growth can reduce the effective height of an elevated instrument above the ground
and can created unwanted space-charge due to corona discharge. Gravel rings or concrete pads
around a site are recommended to prevent changes in effective instrument height due to
vegetation growth. For example, electric field meters used for lightning warning at Kennedy
Space Center were each installed on a 8 m (25 ft) radius gravel ring [LPLWS].
Animals and people within the vicinity of an electric field meter can significantly alter the
measurements. Fencing off a given site may be best for some applications. However, corona
discharge from sharp metal points on even a small fence may cause corruption of measurements
of large electric fields.
The presence of aerosols, dust, and automobile exhaust should be considered when selecting an
electric field meter site, as they can affect the local electric field.
In theory, the effects of tall nearby objects can be accounted for in a site correction. Yet, because
of possible corona current along with general field distortion, it is recommended that electric
field meter sites should not be located near tall objects. For example, Kennedy Space Center site
requirements stipulate having no objects protruding higher than 18° above the horizon, as seen
from the ground at the electric field meter location [LPLWS]. Roof-mounted CS110 systems are
practical if a site correction can be done to account for field distortions.
A good earth ground connection to the CS110 and associated mounting hardware is necessary to
make a given site appear as a vertical extension of the earth ground. Periodically check the
integrity of this earth ground connection by verifying that the resistance of the stator to earth
ground rod is <1 Ω.
Although the list of factors that can impair electric field measurements is long, experience has
shown that useful electric field measurements can be made by paying careful attention to these
details.
CS110 Electric Field Meter 7
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