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5 Thermal Considerations
The thermal characteristic graphs shown in the following sections are intended to serve as guidance
for reconciling the required computing power with the necessary system volumetric airflow over the
ambient temperature. The graphs contain two curves representing upper level working points based on
different levels of average CPU utilization. When operating below the corresponding curve, the CPU
runs without any intervention of thermal supervision (the CPU is below 100°C). When operated above
the corresponding curve, various thermal protection mechanisms may take effect resulting in tempo-
rarily reduced CPU performance or finally in an emergency stop (the CPU is at 125°C) in order to protect
the CPU and the chipset from thermal destruction. In real applications this means that the board can
be operated temporarily at a higher ambient temperature or at a reduced flow rate and still provide
some margin for temporarily requested peak performance before thermal protection will be activated.
An airflow of 2.0 m/s to 3.0 m/s is a typical value for a standard Kontron ASM rack. For other racks or
housings the available airflow will differ. The maximum ambient operating temperature must be deter-
mined for such environments.
How to read the diagram
Select a specific CPU and choose a specific working point. For a given flow rate there is a maximum air-
flow input temperature (= ambient temperature) provided. Below this operating point, thermal super-
vision will not be activated. Above this operating point, thermal supervision will become active
protecting the CPU from thermal destruction. The minimum airflow rate provided must be more than
the value specified in the diagram.
Volumetric flow rate
The volumetric flow rate refers to an airflow through a fixed cross-sectional area (i.e. slot width x
depth. The volumetric flow rate is specified in m³/h (cubic-meter-per-hour) or cfm (cubic-feet-per-
minute) respectively.
Conversion: 1 cfm = 1.7 m³/h; 1 m³/h = 0.59 cfm
Airflow
At a given cross-sectional area and a required flow rate, an average, homogeneous airflow speed can
be calculated using the following formula:
Airflow = Volumetric flow rate / area.
The airflow is specified in m/s (meter-per-second) or in fps (feet-per-second) respectively.
Conversion: 1 fps = 0.3048 m/s; 1 m/s = 3.28 fps
The following figures illustrate the thermal operational limits of the CP6005(X)-SA taking into consid-
eration power consumption vs. ambient air temperature vs. airflow rate.
Note:
The CP6005(X)-SA must be operated within the thermal operational limits indicated be-
low.
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User Guide
CP6005(X)-SA
60
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