Planet GS-5220 Series, User Manual, Page: 495 / 568

User’s Manual of GS-5220 LCD Series
495
4.16.2 System Configuration
In a power over Ethernet system, operating power is applied from a power source (PSU or power supply unit)
over the LAN infrastructure to
powered devices (PDs) , which are connected to ports. Under some conditions,
the total output power required by PDs can exceed the maximum available power provided by the PSU. The
system may come with a PSU capable of supplying less power than the total potential power consumption of all
the PoE ports in the system. In order to maintain the activity of the majority of ports, power management is
implemented.
The PSU input power consumption is monitored by measuring voltage and current .The input power
consumption is equal to the system’s aggregated power consumption .The power management concept allows
all ports to be active and activates additional ports, as long as the aggregated power of the system is lower than
the power level at which additional PDs cannot be connected .When this value is exceeded, ports will be
deactivated, according to user-defined priorities. The power budget is managed according to the following
user-definable parameters: maximum available power, ports priority, maximum allowable power per port.
Reserved Power determined by
There are five modes for configuring how the ports/PDs may reserve power and when to shut down ports.

Classification mode
In this mode, each port automatically determines how much power to reserve according to the class the
connected PD belongs to, and reserves the power accordingly. Four different port classes exist and one for
4, 7, 15.4 and 72 watts.
Class Usage
Range of maximum power used by the
PD
Class Description
0 Default 0.44 to 12.95 watts Classification unimplemented
1 Optional 0.44 to 3.84 watts Very low power
2
Optional 3.84 to 6.49 watts Low power
3 Optional 6.49 to 12.95 watts (or to 15.4 watts) Mid power
4 Optional 12.95 to 60 watts (or to 72 watts) High power