eSpace Audio Recorder
Maintenance Guide
3 Manual Maintenance
Issue 01 (2012-10-15)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd
17
3.3.1 Checking the Relative Humidity and Electromagnetic
Interference
The following describes how to check the relative humidity and electromagnetic interference
in the equipment room.
Reference Standard
z
The relative humidity in the equipment room ranges from 5% to 95% (without
condensation).
z
The equipment room is free of interference from external electronic devices, such as fans,
air conditioners, and RF generators in a transmission equipment room.
z
The equipment room is free of electromagnetic interference from power supplies. The
interference includes voltage surges and industrial frequency interference.
z
The equipment room is free of electromagnetic interference generated by lightning and
high-voltage lines.
Standards: The electric field strength is smaller than 130 dB (
μ
V/m). The magnetic field strength is
smaller than 800 A/m.
Operation Procedure
Step 1
Observe the hygrometer.
z
If the relative humidity in the equipment room is greater than 95%, equip the room with
dehumidifiers.
z
If the relative humidity in the equipment room is less than 5%, equip the room with
humidifiers.
Step 2
Take proper measures to protect the equipment room against interference from external
electromagnetic environments and protect devices against mutual interference. The measures
include closing the cabinet door, inserting filler panels into free slots, and grounding devices.
----End
3.3.2 Checking the Grounding System
This task enables you to regularly maintain the grounding system of the devices (once a half
year is recommended) so that devices can run stably for a long term.
Background
The devices adopt the associated grounding mode, that is, the working ground (GND),
protection ground (PGND), and DC ground (RTN) share one grounding body. The modes are
described as follows:
z
GND: indicates the working ground for the circuits in various components in a cabinet.
GND is the common name for the digital ground and the analog ground of boards.
z
PGND: a protection ground for cabinets and the metal shells of various components in
cabinets.
