Bacharach GDA-1600, Инструкция по эксплуатации

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Instruction 5700-9001 GDA-1600 16-Channel Controller
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electromagnetic energy in the air can induce high voltage surges from lightning activity
several miles away.
8.6.1 Antenna Grounding
Electromagnetic energy in the air will be drained to ground via any and every earth path.
An earth path exists between the antenna and the GDA-1600 and to protect against
damage this earth path current must be kept as small as possible. This is achieved by
providing better alternate earth paths. It is important to ground the antenna to the same
ground point as the GDA-1600. Antennas are normally mounted to a metal bracket
which should be grounded to the GDA-1600 earth connection. Surge energy induced into
the antenna will be drained first by the mount’s ground connection, second by the outside
shield of the coax cable to the ground connection on the radio and third by the internal
conductor of the coax cable via the radio electronics
When an antenna is located outside of a building and outside of an industrial plant
environment, external coax surge diverters are recommended to further minimize the
effect of surge current in the inner conductor of the coax cable.
. This third earth path causes damage
unless the other two paths provide a better earth connection allowing surge energy to
bypass the electronics.
Coax surge diverters have gas-discharge element which breaks down in the presence of
high surge voltage and diverts any current directly to a ground connection. A surge
diverter is not normally required when the antenna is within a plant or factory
environment, as the plant steelwork provides multiple parallel ground paths and good
earthing will provide adequate protection without a surge diverter.
8.6.2 Connections to Other E quipment
Surges can enter the wireless unit from connected devices, via I/O, serial or Ethernet
connections. Other data devices connected to the wireless unit should be well grounded to
the same ground point as the wireless unit.
Special care needs to be taken where the connected data device is remote from the
wireless unit requiring a long data cable. As the data device and the wireless unit cannot
be connected to the same ground point, different earth potentials can exist during surge
conditions.
There is also the possibility of surge voltages being induced on long lengths of wire from
nearby power cables. Surge diverters can be fitted to the data cable to protect against
surges entering the wireless unit.
The same principle applies to I/O devices that are not close to the wireless unit—the risk
of surge increases.