Maintaining The M320 Sibs - Juniper M320 Hardware Manual

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Maintaining the M320 SIBs

Purpose
Action
Copyright © 2015, Juniper Networks, Inc.
8.0 V bias
5.0 V bias
NOTE: Isolated DC power supplies share current over the full input
operating voltage range.
The current sharing between nonisolated power supplies relies on equal
voltages at the power supply input terminals. The M320 system power is
divided into two load zones. One load zone consists of PEM0 and PEM2,
and the other load zone consists of PEM1 and PEM3. For nonisolated power
supplies, load sharing occurs only between the power supplies of each load
zone (PEM0 and PEM2 or PEM1 and PEM3). Therefore, the voltages for
each nonisolated power supply in a load zone should be equal for current
sharing. However, if the voltages do not match, the router operates normally
as long as the DC input voltages are within the operating range provided
in "M320 DC Power Electrical Specifications" on page
Power Cable Specifications" on page 107
arrangement.
Routinely check the OUTPUT OK
faceplates and the craft interface. If these output status LEDs are lit, the power supplies
are functioning normally. For more information about the power supply LEDs, see
"M320 Power System Description" on page
Check the red and yellow alarm LEDs and the LED display on the craft interface. Power
supply failure or removal triggers an alarm that causes one or both of the LEDs to light
and an error message to appear on the LED display. You can display the associated
error messages by issuing the following CLI command:
user@host> show chassis alarms
For a list of possible alarm messages, see
on page 285.
Troubleshooting the M320 Power System on page 292
Replacing an M320 AC Power Supply on page 247
Replacing an M320 DC Power Supply on page 250
For optimum router performance, verify the condition of the SIBs.
On a regular basis:
Observe the status of the SIBs by checking the LEDs on the SIB faceplate or craft
interface. For more information on the SIB LEDs, see
"M320 Craft Interface SIB LEDs" on page
Chapter 31: Maintaining Components and Cables
8485 mV
4996 mV
for a typical DC source cabling
and the POWER OK status LEDs on the power supply
73.
"M320 Chassis and Interface Alarm Messages"
"M320 SIB LEDs" on page 81
19.
105. See "M320 DC
and
279