January/February 2019 I59
PDU manufacturers use various
names for the functions, but
following are the four basic models
of intelligent PDUs:
MONITORED — Provides
measurement at the rack level.
Measures total power used by
all attached equipment. Ideally,
it will also provide input and branch
monitoring for proper
load balancing.
MONITORED PRO (outlet monitored) —
Includes measurement at each outlet
to provide device-level measurement.
Ideally, it will also include the ability
to group outlets across multiple units
to see easily the total power for dualcorded
devices.
SWITCHED — Provides the ability
to turn outlets on and off remotely,
allowing remote reboot of
equipment and forced off conditions
for unused outlets. This feature is
especially beneficial in colocated
equipment, as it may reduce remote
hands charges and simplify and
speed correction in enterprise sites.
Forcing outlets off also prevents
accidental overloads and requires
some formal process to energize any
new equipment in the rack. This
typically includes grouping of outlets
to toggle dual-corded equipment and
timed responses to control the order
and timing of reboots.
SWITCHED PRO (all features) — The
most robust solution controls all
functions, providing unit (rack) level
monitoring, outlet (device) level
monitoring, and outlet (device)
level control.
Other critical features to look for in
an intelligent PDU include:
• Locking outlets to prevent
accidental disconnections
• High temperature rating to ensure
monitoring as temperatures within
the rack rise
• IP consolidation to reduce
networking costs
• Secondary IP to provide redundant
connection (failover capability)
• Integrated environmental
monitoring to monitor inlet and
outlet temperatures, ensuring
properly conditioned supply air
and reduced expense of a separate
subsystem
• Integrated electronic locks to
provide physical security and
meet regulatory compliance
requirements
• Built-in administration, security,
threshold, notification and
logging functions
Functionality Basic Power
Inlet
Metering
Branch
Circuit
Metering
Networking Access
Control
Outlet
Metering
Switched
Outlets
Monitored - to monitor total
power usage.
Monitored Pro - to remotely
measure individual power
used by each piece of
equipment.
Switched - to remotely turn
power on or off at
each outlet.
Switched Pro - to remotely
measure and control power
at each outlet.
“Organizations spent
$608 million in
intelligent PDUs in
2017, placing revenue
for intelligent PDUs at
more than 65 percent
of the overall
rack power distribution
global market.”
TABLE 1: Critical features of intelligent PDU models.