Description

This article describes the issue of the  PEM 0 Dipswitch 0 Feed Connection 2  alarm being generated, when the switch position of the MX960 High Capacity DC PEM DIP device is in 0 .

Symptoms

For a MX960 High Capacity DC PEM with 2 feeds, incorrect setting of this DIP switch in position 0 will generate the following alarms in the chassis:

user@voodoo-re1> show chassis alarms
4 alarms currently active
Alarm time Class Description
2013-01-11 14:48:26 UTC Minor PEM 0 Dipswitch 0 Feed Connection 2 <
user@voodoo-re1>

Solution

For MX960 routers, each High Capacity DC PEM will accept two DC feeds (labeled as INP0 and INP1 ). It is possible to operate with one feed; but with lower power output. The DIP switch on the PEM is near the on/off switch. This DIP switch should be set according to the number of DC feeds that are present for the PEM.
 

  •     Position 0: Indicates that only one DC feed is provided.
  •     Position 1: Indicates that two DC feeds are provided.

When two feeds are connected to the PEM and if the DIP switch is in the 0 position, it will cause the PEM 0 Dipswitch 0 Feed Connection 2 alarm. You have to place the DIP switch in the position of 1 , so that it can have two feeds and clear the alarm.

NOTE: Flipping the dip switch will not impact traffic. However, it is recommended to do so in a maintenance window to guard against unforeseen circumstances.

The following image illustrates the DIP switch (Input mode switch):


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The following example illustrates the alarm:

The PEM0 DIP switch was set to the 0 position; the alarm was generates and the PEM capacity is displayed as 1700W :
user@voodoo-re1> show chassis alarms
4 alarms currently active
Alarm time Class Description
2013-01-11 14:48:26 UTC Minor PEM 0 Dipswitch 0 Feed Connection 2
user@voodoo-re1> show chassis power

PEM 0:
State: Online
DC input: OK (1 feed expected, 2 feed connected) < When the DIP switch in the '0' position
DC input: 48.0 V input (57000 mV)
Capacity: 1700 W (maximum 4100 W) < Capacity lowered to 1700W
DC output: 1026 W (zone 0, 18 A at 57 V, 60% of capacity)

When PEM0 DIP in position 1 then there is no alarm,   
"show chassis power" shown - DC input: OK (2 feed expected, 2 feed connected)
===================================================================================================
user@voodoo-re1> show chassis power

PEM 0:
State: Online
DC input: OK (2 feed expected, 2 feed connected) < When the DIP switch in the '1' position
DC input: 48.0 V input (57500 mV)
Capacity: 4100 W (maximum 4100 W) < Capacity is 4100W 
DC output: 969 W (zone 0, 17 A at 57 V, 23% of capacity)
user@voodoo-re1>

Modification History

2019-07-13: Undated incorrect DIP switch position from '11' to '1'.

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