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Cooling Subsystem
6.1
Overview
This section contains information on fans and fan trays.
6.2
Cooling Subsystem
The shelf manager provides cooling management to the AdvancedTCA shelf to keep the shelf
cool under normal operation conditions. The shelf manager adjusts the fan levels to adapt to
the changing conditions of the shelf elements or environment.
The Centellis 2000 provides fault tolerant cooling to front-mounted AdvancedTCA blades and
to rear transition modules, based on two intelligent fan trays. Each tray houses two fans. One
fan tray is located at the front, the other at the rear of the shelf. The airflow direction in the shelf
is from front to rear.
The cooling system is able to provide greater than 46 CFM for the front blade and greater than
7.5 CFM for the RTM in each slot.
Actual cooling performance also depends on the slot population and the heatsink design of the
installed blades, and it should be validated based on the used system configuration.
The distance to other equipment must be sufficient to avoid an overheating of the system.
Each of the fan tray units contains an IPMC which is located on both IPMB-A and IPMB-B buses.
Individual fan failures are detected by monitoring the fan rotation speed. Rotation which
differs more than 20% of the set value is deemed to be a fan failure. Usually, the cooling system
runs the fans at speed levels between 15% and 75%, depending on ambient temperature and
system configuration. In case of single fan failure the cooling will increase the speed of the
remaining fans accordingly.
Each fan tray monitors and reports air temperature and failure conditions to the shelf manager.
The shelf manager controls the fan speed based on sensor and failure information acquired
from fan and board sensors. If a fan tray loses IPMI communication to the shelf manager, it
automatically runs its fan motor at full speed.
Centellis 2000 Shelf Release 3.0 Installation and Use (6806800L99F)
Chapter 6
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