Kipp & Zonen CM 11, Instruction Manual

Page: 45 / 64

FREQUNTLY
ASKED QUESTIONS
44
Good ventilation of domes and body is the solution to reducing zero offsets
even further. Kipp & Zonen advises the CV 2 for optimal ventilation and
suppression of zero offset type A. Using the CV 2 zero offset type A will be
less than 3 W/m
2
.
2. Maximum and minimum irradiation quantities?
Due to possible reflection from clouds the global irradiance at sea level can
rise above the extraterrestrial irradiance of 1367 W/m
2
at the top of the
atmosphere. Values up to 1500 W/m
2
have been reported.
Because the clouds move, this irradiance value mostly appears as short
events of some minutes duration.
3. What is the primary entry point for humidity ?
The desiccant cartridge and cable glands have equal chances to transport
some moisture but also the silicon glue of the domes is not fully watertight.
However, normally the cable gland is never touched while the cartridge is
removed frequently.
So when no care is taken (see above) one can easily make the desiccant
cartridge the primary entry point.
Note. Water transport through the cable is also possible when the open
end of the cable and the connected device are in a humid
environment