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The CPU diode temperature can be used to prevent damage to the board by shutting
the board down if this sensor exceeds predetermined limits.
Adjusting the Environmental
Monitoring Warning, Critical, and
Shutdown Parameter Settings on the
Board
The Netra CP2500 uses the environmental monitoring detection system to monitor
the temperature of the board. The environmental monitoring system will display
messages if the board temperature exceeds the warning and critical settings. Because
the on-board sensors may report different temperature readings for different system
configurations and airflows, you might want to adjust the warning, critical, and
shutdown temperature parameter settings.
The Netra CP2500 determines the board temperature by retrieving temperature data
from sensors located on the board. A board sensor reads the temperature of the
immediate area around the sensor. Although the software might appear to report the
temperature of a specific hardware component, the software is actually reporting the
temperature of the area near the sensor. For example, the CPU diode sensor reads
the temperature at the location of the sensor and not on the actual CPU heat sink.
The board's OpenBoot PROM collects the temperature readings from each board
sensor at regular intervals. You can display these temperature readings using the
show-sensors OpenBoot PROM command. See
"Using the show-sensors
Command at the OpenBoot PROM" on page
34.
The temperature read by the CPU sensor will trigger OpenBoot PROM warning and
critical messages. When the CPU sensor reads a temperature greater than the
warning parameter setting, the OpenBoot PROM will display a warning message.
When the sensor reads a temperature greater than the shutdown setting, the SMC
will shut down the board.
Many factors affect the temperature readings of the sensors, including the airflow
through the system, the ambient temperature of the room, and the system
configuration. These factors might contribute to the sensors reporting different
temperature readings than expected.
The Netra CP2500 board CPU sensor default temperature threshold values are 110˚C
for the high warning temperature, 118˚C for the high shutdown temperature, and
123˚C for the high power-off temperature.
32
Netra CP2500 Board Programming Guide • March 2007
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