A:
The temperature measured is related with the position where the temperature sensor is placed.
Some sensors are integrated on the boards, while the boards are usually installed at the air exhaust
vent at the upper part of the cabinet. Some sensors may be installed at the top of the cabinet,
also near the air exhaust vent. Therefore, the reported temperature is usually higher than the
actual temperature.
For the sensor integrated on the board, the temperature measured will also be higher than the
actual temperature since the board will generate heat during running.
2. Q: Why is the humidity measured by the humidity sensor different from the actual
humidity?
A:
The possible reasons are as follows:
l
The humidity is affected by the temperature. The temperature is reciprocal with the relative
humidity, so, the higher the temperature, the lower the relative humidity.
l
In general, the temperature sensor and the humidity sensor are integrated together in
Huawei. The integrated sensor may be installed at the top of the cabinet. Since the
temperature at the exhaust vent is higher than the actual temperature, the relative humidity
of that area will become lower.
l
It is also the same for the temperature and humidity sensor on the board. The temperature
at the board surface is higher than the environment temperature due to the heat generated
by the board components, and accordingly, the relative humidity is also lower than the
actual humidity.
l
The humidity sensor is vulnerable to damage, calibrate it once every one to two years.
However, some sensors may have not been calibrated after running for years, and the
detection result may differ from the actual value.
l
Temperature performance: The humidity sensor can detect the humidity successfully when
the temperature is less than 25°C. The accuracy will be affected by the change of the
environment temperature.
3. Q: The temperature and humidity exceed the thresholds, but no alarm is generated, and
the temperature and humidity are displayed as normal. What is the reason?
A:
Such phenomenon happens when the temperature and humidity are at the critical values. The
reason is that the board and host will round up the values at calculating, but the error is not too
large.
10.1.3 Door Status Sensor
The door status sensor monitors the status of the cabinet door.
Appearance
The door status sensor uses a magnetic switch as the probe. The magnetic switch consists of two
built-in parts. The reeds of the magnetic switch are attracted together through electromagnetic
interaction. The output signals are dry-contact output signals without polarity.
shows the appearance of the door status sensor.
UA5000 Universal Access Unit
Environment Monitoring
10 Sensors
Issue 01 (2012-08-17)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
171
