2-2
Besides, the amounts of salt, acid, and sulfide in the equipment room should be strictly restricted.
Harmful gases could accelerate the corrosion of metal parts and the aging of some parts.
Table 2-3 lists the concentration limit of SO
2
, H
2
S, NH
3
, and CI
2
in the equipment room.
Table 2-3
Concentration limit of some harmful gases in the equipment room
Gas
Max content (mg/m
3
)
SO
2
0.2
H
2
S 0.006
NH
3
0.05
Cl
2
0.01
Electrostatic Discharge Prevention
In the communication network to which the device is connected, static induction mainly results from:
z
External electrical fields such as outdoor high voltage power line or lightning
z
Indoor environment, flooring materials, and the device structure
Although the V100-E adopts many antistatic measures, damage to board circuits or even the device
may still happen when the static electricity exceeds a certain limit.
To prevent ESD,
z
Make sure that the device and the floor are well grounded.
z
Take dust-proof measures for the equipment room.
z
Maintain the humidity and temperature at a proper level.
z
Always wear an ESD-preventive wrist strap or antistatic clothing when touching a circuit board.
z
Place the removed circuit board on an antistatic workbench, with the face upward, or put it into an
antistatic bag.
z
Hold by the edges, instead of electronic components when observing or moving a circuit board.
Electromagnetic Interference Prevention
All possible interference sources, external or internal, affect the device in the way of capacitance
coupling, inductance coupling, electromagnetic radiation, and common impedance (including the
grounding system) coupling. To minimize the influence of interference sources on the device, take the
following into consideration:
z
Take effective measures to protect the power system from power grid interference.
z
Separate the protection ground of the device from the grounding device or lightning protection
grounding device of the common power supply equipments as far as possible.
z
Keep the device far from heavy-duty radio transmitters, radar transmitters, and high-frequency
devices.
z
Adopt electromagnetic shielding measures when necessary.
Lightning Protection
Although many measures have been taken to protect the device from lightning, damage to the device
may still happen if the lightning intensity exceeds a certain limit. To better protect the device from
lightning, do the following:
