H3C Technologies H3C WX6000 Series Access Controllers - Manual (Page 24)

16
CAUTION:
If condensation appears on the access controller when you move it to a high-temperature environment,
dry the access controller before powering it on to avoid short circuits.
Cleanliness requirements
Dust is a hazard to the operating safety of your access controller. Dust buildup on the chassis may result
in electrostatic adsorption, which causes poor contact of metal components and contact points,
especially when indoor relative humidity is low. In the worst case, electrostatic adsorption can cause
communication failure.
Table 15 Dust concentration limit in the equipment room
Substance Concentration limit (particles/cu m)
Dust particles
≤ 3 x 10 4
(No visible dust on desk in three days)
NOTE:
Dust particle diameter ≥ 5 μm
In addition, the equipment room should meet strict limits on salts, acids and sulfides to eliminate
corrosion and premature aging of components, as shown in
Table 16 .
Table 16 Harmful gas limits in an equipment room
Gas Max. (mg/m 3 )
SO
2
0.2
H
2
S 0.006
NH
3
0.05
Cl
2
0.01
EMI requirements
All electromagnetic interference (EMI) sources, from outside or inside of the access controller and
application system, adversely affect the access controller in a conduction pattern of capacitance
coupling, inductance coupling, electromagnetic wave radiation, or common impedance (including
grounding system) coupling. To prevent EMI, perform the following steps:
• Take measures against interference from the power grid.
• Do not use the access controller together with the grounding equipment or light-prevention
equipment of power equipment, and keep the access controller far away from them.
• Keep the access controller far away from high-power radio launchers, radars, and equipment with
high frequency or high current.
NOTE:
Use electromagnetic shielding when necessary.