User’s Manual of WGR-500-4P and WGR-500-4PV
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4.5.2 System Configuration
In a power over Ethernet system, operating power is applied from a power source (PSU) 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. 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 Management
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 30.8 watts.
Class
Usage
Range of maximum power used by the PD
Class Description
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 15.4 watts)
Mid power
4
Optional
12.95 to 25.50 watts (or to 30.8 watts)
High power
1. In this mode the
Maximum Power fields
have no effect.
2. The PoE chip of PD69012 designed to that Class level 0 will be assigned to 15.4 watts
in AF mode and 30.8 watts in AT mode under classification power limit mode. It is
hardware limited.
