PLANET SGS-5220-24P2X - Manual (Page 312)

User’s Manual of SGS-5220 Series
4.16.2 System Configuration
In a power over Ethernet system, operating power is applied from a power source (PSU-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 a prior be planed 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
majority of ports active, 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 automatic 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 30.8 Watts.
Class Usage Range of maximum power used by the PD Class Dsecription
0 Default 0.44 to 12.95 Watts Classification unimplement
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 15.4Watts) Mid power
4 Optional 12.95 to 25.50 Watts (or to 30.8Watts) High power
1. In this mode the Maximum Power fields have no effect.
2. The PoE chip of PD69012 has designed to that Class level 0 will be assigned to 15.4
watts by AF mode and 30.8 watts by AT mode under classification power limit mode. It is
hardware limited.
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