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Software Configuration Guide—Release 12.2(25)SG
OL-7659-03
Chapter7 Environmental Moni toring and Power Management
Power Management
Keep in mind the following guidelines when using a 1400 W DC power supply with your Catalyst 4500
series switch:
•The 1400 W DC power supply works with a variety of DC sources. The DC input can vary from
300 W to 7500 W. Refer to the power supply documentation for additional informatio n.
•The supervisor engine cannot detect the DC source plugged into the 1400 W DC power supply. If
you are using the 1400 W DC power supply, use the power dc input command to set the DC input
power. For more information on this command, see the “Configuring the DC Input for a Power
Supply” section on page 7-13.
•The software automatically adjusts between system power (for module s, backplane, and fans) and
PoE. Although PoE is 96 percent efficient, system power has only 75 percent efficiency. For
example, each 120 W of system power requires 160 W from the DC input. This requirement is
reflected in the “Power Used” column of the output for the show power available command.
•The 1400 W DC power supply does not support combined mode. If y ou set the power budget to 2
(combined mode), the switch allows you to configure combined modes but disregards the setting and
remains in redundant mode.
•The 1400 W DC power supply has a separate power on or off switch for PoE. The power supply fan
status and main power supply status are tied together. If either of them fails, both the power supply
and its fan report as bad/off. You should verify that the main power is on before turning on the power
for the inline switch. In addition, you should verify that the power for the inline switch is off before
turning off the main power.
Configuring the DC Input for a Power Supply
To configure the DC input power for the 1400 W DC power supply or a power shelf, perform this task:
The same configuration is applied to both power slots. For example, if you set the dc power input to
1000 W, the switch expects 1000 W as the external DC source for both slot 1and slot 2 (if pr esent)
respectively.
The following example shows how to set the external DC power source to 1000 W:
Switch# configure terminal
Switch (config)# power dc input 1000
Switch (config)# end
Switch#
If you use the 1400 W DC SP power supply in combined mode, the i nputs do not have to match.
Command Purpose
Step1 Switch# configure terminal Enters configuration mode
Step2 Switch(config)# power dc input
watts
Sets the capacity of the DC input source.
Step3 Switch(config)# end Exits configuration mode.