2-2
Especially when the indoor relative humidity is low, electrostatic adsorption is more likely to happen.
This can not only shorten the service life of your device but also cause communications failures. The
following table lists the dust concentration limit.
Table 2-1
Dust concentration limit in the equipment room
Substance
Unit
Concentration limit
Dust
Particles/m³
≤
3 x 10
4
(no visible dust on the tabletop
within three days)
Note: The dust particle size
≥
5
μ
m.
Besides dust, there are rigorous limits on the content of harmful substances in the air that can
accelerate the corrosion and aging of metals, such as chloride, acid, and sulfide in the equipment room,
and the equipment room must be protected against ingression of harmful gases such as SO
2
, H
2
S, NH
3
,
and Cl
2
. For specific requirements, see the following table.
Table 2-2
Harmful gas limits in the equipment room
Gas
Maximum concentration (mg/m
3
)
SO
2
0.2
H
2
S 0.006
NH
3
0.05
Cl
2
0.01
Electromagnetic Susceptibility
The operation of your switch can be affected by external interferences, such as conducted emission by
capacitance coupling, inductance coupling, electromagnetic wave radiation, and common impedance
(including the grounding system) coupling, and leads (power cords, signaling cables and output wires).
To eliminate the interferences, pay attention to the following:
z
As the AC power system is a TN system, use a single-phase three-wire power socket with
Protection Earth (PE) to effectively filter interference from the power grid.
z
Keep the device far from radio transmitting stations, radar stations, and high-frequency devices.
z
Use electromagnetic shielding when necessary, for example, use shielded interface cables.
z
Route interface cables only indoors to prevent signal ports from getting damaged by overvoltage or
overcurrent caused by lightning strikes.
Laser Safety
The S5120-EI series are Class 1 laser devices.
When the optical ports on the S5120-EI series are operating, do not stare into the optical ports because
the laser light emitted by the optical fiber may hurt your retina.
