4
EMI
All electromagnetic interference (EMI) sources, from outside or inside of the device and application
system, adversely affect the device 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:
•
Take effective measures to filter interference from the power grid.
•
Keep the protection ground of the device away from the grounding facility of power equipment
or lightning protection grounding facility.
•
Keep the device far away from radio transmitting stations, radar stations, and high-frequency
devices.
•
Use electromagnetic shielding, for example, shielded interface cables, when necessary.
Lightning protection
To enhance lightning protection for the device, follow these guidelines:
•
Make sure the device is reliably grounded.
•
Make sure the AC power outlet is reliably grounded.
•
Install a lightning protector at the power input end.
•
Install a lighting protector at the input end of signal cables routed from outdoors.
Rack requirements
To install the device in a rack, make sure the rack meets the following requirements:
•
The rack has a good ventilation system.
•
The rack is sturdy and can support the device and its accessories.
•
The rack has a size that can accommodate the device.
•
Enough clearances are reserved at the two sides of the device for heat dissipation.
•
A minimum clearance of 0.8 m (2.62 ft) is reserved between the rack and walls or other devices
for heat dissipation and maintenance.
•
The headroom in the equipment room is not less than 3 m (9.84 ft).
