IBM s-series, Инструкция по установке и эксплуатации, Страница: 91 / 170

The low and high temperature thresholds enable the device to determine at which
speed the fans should operate. In general, the fans operate as follows:
v If the temperature of all thermal planes is between the low and high thresholds
for a fan speed, the fan continues to operate at that fan speed.
v If the temperature of any thermal plane exceeds the high threshold specified for
a fan speed, the fan speed increases to the next higher speed. If the temperature
of any thermal plane exceeds the high threshold for the high speed and remains
above the threshold for five minutes, the system automatically shuts down to
prevent damage.
v
If the temperature of any thermal plane falls below the low threshold for a fan
speed, the fan decreases its speed to the next lower speed. If the temperature of
any thermal plane falls below the high threshold for the low speed, the fan
operates at the low speed.
If the temperature of any thermal plane exceeds the high temperature threshold for
any of the fan speeds, the software sends a message to the system log.
Table 20 outlines the default low and high temperature thresholds for each fan
speed, as well as the operating level and noise level of the fans at each fan speed.
Table 20. Fan speed, temperature thresholds and fan noise levels on the B08S
Fan Speed Description
Low Temperature
Threshold High Temperature
Threshold
Fan Operating
Level (% of
Capacity)
Fan Noise
Level
4 High 50° C 80° C 100 78 dB
3 Medium 49° C 59° C 50 66 dB
H i gh temper a ture threshold
(shutdown temper a ture)
Low temper a ture threshold
HIGH
MEDIUM
LOW
H i gh temper a ture threshold
Low temper a ture threshold
H i gh temper a ture threshold
MEDIUM-LOW
H i gh temper a ture threshold
Low temper a ture threshold
net
0
8bs
0
47
Figure 31. Fan speeds and temperature thresholds on the B08S
Chapter 5. Managing the Chassis and Modules
65