Rockwell Automation 1783-Mxxx Stratix 8000 and 8300 Ethernet Managed Switches User Manual - Manual (Page 63)

Rockwell Automation Publication 1783-UM003I-EN-P - March 2014 63
Switch Software Features Chapter 3
If the module detects a fault caused by an undervoltage, overvoltage,
overtemperature, oscillator-fault, or short-circuit condition, it turns off power to
the port, generates a syslog message, and updates the power budget and status
indicators.
Power Management Modes
PoE expansion module ports support these modes:
• Auto (default)—The port automatically detects if the connected device
requires power. This is the default mode. If the port discovers a connected
powered device and the module has enough power, it grants power,
updates the power budget, turns on power to the port on a first-come,
first-served basis, and updates the status indicators. For status indicator
information, see
PoE Port Status Indicator on page 179 .
If enough power is available for all powered devices connected to the
module, power is turned on to all devices. If there is not enough available
power to accommodate all connected devices and if a device is
disconnected and reconnected while other devices are waiting for power, it
cannot be determined which devices are granted or are denied power.
If granting power exceeds the system power budget, the module denies
power, verifies that power to the port is turned off, generates a syslog
message, and updates the status indicators. After power has been denied,
the module periodically rechecks the power budget and continues to
attempt to grant the request for power.
If a device being powered by the module is then connected to wall power,
the module can continue to power the device. The module can continue to
report that it is still powering the device whether the device is being
powered by the module or receiving power from an AC power source.
If a powered device is removed, the module automatically detects the
disconnect and removes power from the port. You can connect a
nonpowered device without damaging it.
You can specify the maximum wattage that is allowed on the port. If the
IEEE-class maximum wattage of the powered device is greater than the
configured maximum value, the module does not provide power to the
port. If the module powers a powered Cisco end device, but the powered
device later requests through CDP messages more than the configured
maximum value, the module removes power to the port. The power that
was allocated to the powered device is reclaimed into the global power
budget. If you do not specify a wattage, the module delivers the maximum
value.