2-3
metallic corrosion and the aging process of some parts. The specific limits of the harmful gases such as
are given in the following table.
Table 2-3
Limit on harmful gases 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
Anti-Static Requirements
Generation and damage of static electricity
In the communication network to which the WX5004 is connected, static induction of the access
controller mainly comes from the following sources:
z
External electric fields, such as outdoor high-voltage transmission lines or thunderbolts.
z
Internal environment like flooring materials or the structure of the overall system.
Although the WX5004 is designed to be Electrostatic Discharge (ESD) preventive, excessive static
electricity may enormously damage the card circuits or even the whole device.
Protection measures
To prevent electrostatic damage, observe the following:
z
Ensure that the access controller and the floor is well grounded.
z
Keep the equipment room clean.
z
Maintain suitable temperature and humidity;
z
Wear ESD-preventive gloves or an ESD-preventive wrist strap and uniform when handling the
circuit board.
z
Hold the interface module only by its edge when installing, observing or removing it. Do not touch
the components on it.
z
Place the removed interface module on an ESD-preventive workbench with the component-side
facing upward or place it in an antistatic bag.
Wearing ESD-Preventive Wrist Strap
No ESD-preventive wrist strap is shipped with the access controller. You need to purchase one if
needed.
Follow these steps to use an ESD-preventive wrist strap:
1) Put on the ESD-preventive wrist strap.
2) Fasten the ESD-preventive wrist strap and verify that it makes good skin contact.
