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Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 10 Environmental Monitoring and Power Management Power Management
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 present).
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 inputs do not have to match.
Special Considerations for the 1400 W DC SP Triple Input Power Supply
Unlike the 1400 W DC power supply, the 1400 W DC SP power supply has submodules (multiple inputs)
that can be powered on or off. With Cisco IOS Release 12.2(25)EW, the output of the
show power command is modified to display the status of these submodules:
Switch# show power
Power Fan Inline
Supply Model No Type Status Sensor Status
------ ---------------- --------- ----------- ------- ------
PS1 PWR-C45-1400DC DCSP1400W good good n.a.
PS1-1 12.5A good
PS1-2 15.0A bad
PS1-3 15.0A off
PS2 none -- -- -- --
Keep in mind the following guidelines when using a 1400 W DC SP power supply with your Catalyst
4500 series switch:
• When you use two 48 V power rails to drive two power supplies, you might use cross-wiring to
connect the power supplies (to rails) to minimize the inrush current drawn during an initial power
up. In this situation, you should configure the switch in combined mode before you take a rail down
for maintenance.
• Ordinarily, when configured for redundancy, two power supplies must be matched (have identical
inputs). For example, you might provide power to inputs 1 and 3 on both PS1 and PS2. If power
supplies are mismatched upon bootup, the right (second) power supply is in err-disable state.
In a matched redundant power supply configuration, if a power supply submodule fails, the other (good)
power supply provides power to its full capability.
Insufficient Inline Power Handling for Supervisor Engine II-TS
When the Supervisor Engine II-TS is used with the 1400 W DC power supply (PWR-C45-1400DC), and
only one 12.5 A input of the power supply is used, the supervisor engine’s power consumption may vary
depending on the type of line card used and on whether a line card is inserted at slots 2 and 3. The power
consumption varies between 155 W and 330 W, which also affects the maximum amount of available
inline power through the supervisor engine (0 W to 175 W). Consequently, it is possible for the
supervisor engine to deny inline power to a connected inline power device when one or more line cards
are inserted into the chassis.
Step 2 Switch(config)# power dc input watts Sets the capacity of the DC input source.
Step 3 Switch(config)# end Exits configuration mode.
Command Purpose