2-2
Cleanliness
Dust buildup on the chassis might result in electrostatic adsorption, which causes poor contact of
metal components and contact points. In the worst case, electrostatic adsorption can cause
communication failure.
Table2-2 Dust concentration limits in the equipment room
Substance
Particle diameter
Concentration limit
Dust particles
≥ 0.5 µm
≤ 1.8×10
7
particles/m
3
Harmful gas limit
Corrosive gases can accelerate corrosion and aging of components. Make sure the corrosive gases
do not exceed the concentration limits as shown in
Table2-3 Corrosive gas concentration limits
Gas
Average concentration (mg/m
3
)
Maximum concentration (mg/m
3
)
SO
2
0.3
1.0
H
2
S
0.1
0.5
Cl
2
0.1
0.3
HCI
0.1
0.5
HF
0.01
0.03
NH
3
1.0
3.0
O
3
0.05
0.1
NO
X
0.5
1.0
EMI
All electromagnetic interference (EMI) sources, from outside or inside of the router and application
system, adversely affect the router in the following ways:
•
A conduction pattern of capacitance coupling.
•
Inductance coupling.
•
Electromagnetic wave radiation.
•
Common impedance (including the grounding system) coupling.
To prevent EMI, use the following guidelines:
•
If AC power is used, use a single-phase three-wire power receptacle with protection earth (PE)
to filter interference from the power grid.
•
Keep the router far away from radio transmitting stations, radar stations, and high-frequency
devices.
•
Use electromagnetic shielding, for example, shielded interface cables, when necessary.
•
To prevent signal ports from getting damaged by overvoltage or overcurrent caused by lightning
strikes, route interface cables only indoors.
