Chapter 5 _________________________________________________________ Theory of Operation
VAISALA _______________________________________________________________________ 109
Battery Backup
The optional battery backup ensures operation for a minimum period of
30 minutes
(at 25 °C) in case of a power failure. If the unit is operating in
a non-freezing environment and the high power hood heaters are not
required, the FS11 sensor can also be operated with DC power. The
battery charger QBR101 also provides interfaces for solar panels and
larger external batteries. Refer to the QBR101 User's Guide for the
connections.
Frangible Mast
The frangible mast is made of a glass fiber tube. The same mast tube
structures are also used in the approach light systems of several airports
around the world. The mast manufacturer Exel has performed frangibility
tests under the supervision of ICAO (International Civil Aviation
Organization ). Reports of these tests are available on special request.
The grounding cable inside the mast is connected to the mast with a fork
type connector. The connector will slide from its attachment screw in
case of an impact to the mast. The measurement unit cable will also slide
through its cable gland in FSI102 and disconnect from the FSC202 in
case of an impact to the mast.