Power Down; Cooling System Functional Description; Cooling Path - Cisco ASR 9000 series Reference Manual

Cooling System Functional Description

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Power Down

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Cooling System Functional Description
The Cisco ASR 9000 Series chassis is cooled by two fan trays located below the card cage. The two fan
trays provide full redundancy and maintain required cooling if a single fan failure should occur.
In the ASR 9010 Router, the fan trays are located one above the other below the card cage, and are
equipped with handles for easy removal.
The fan trays for the ASR 9006 Router are located above the card cage, left of center, side by side. They
are covered by a fan tray door hinged at the bottom, which must be opened to remove the trays.

Cooling Path

The ASR 9010 Router chassis has a front to rear cooling path. The inlet is at the bottom front of the
chassis and exhaust is at the upper rear.
Figure 2-24
The ASR 9006 Router chassis has a side to top to rear cooling path. The inlet is at the right side of the
chassis and exhaust is at the upper rear.
Figure 2-25
Cisco ASR 9000 Aggregation Services Router Overview and Reference Guide
2-30
D R A F T — C I S C O C O N F I D E N T I A L
DC/DC power supplies are enabled by toggling the Power On/Off logic switch located in each of the
power shelf to ON position.
DC/DC power supply modules in the power shelf provides –54 VDC output within two seconds after
the DC is applied.
The soft-start circuit in the logic cards takes 100 ms to charge the input capacitor of the on-board
DC/DC converters.
The card power controller, MCU, enables the power sequencing of the DC/DC converters and POLs
through direct communication using a PMBus interface to digital controllers such as LT7510 or
through a digital wrapper such as LT2978.
The output of the DC/DC converters ramp up to regulation within 50 ms maximum. after the
program parameters are downloaded to each POL and On/Off control pin has been asserted.
Power conversion is disabled by toggling the Power On/Off logic switch in the power shelf to OFF
position.
The DC/DC modules in the power shelf stays within regulation for a minimum of 5 ms after the
Power On/Off logic switch is disabled.
The –54V DC to the logic card ramps down to –36 VDC in 3.5 ms minimum from the time the
DC/DC modules starts ramping down from its minimum regulation level.
The DC/DC converters powers off immediately after the On/Off pin is deasserted.
The output of the DC/DC converters stays in regulation for an additional 100 microseconds.
shows the cooling path for the ASR 9010 Router chassis.
shows the cooling path for the ASR 9006 Router chassis.
Chapter 2 Functional Description
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