Westermo RedFox Series - Manual (Page 257)

Westermo OS Management Guide
Version 4.17.0-0
the resistance is too high to meet the PoE specification (and too low to be
determined as unconnected (open curcuit)).
12.1.2 Allocation of PoE Power
There is maximum value for the amount of power a PoE switch can deliver (P
stch,m
),
see the User Guide of your PoE product[ 52 ] for more information on max output
power. When more power is requested than available, the switch will stop/refuse 1
delivering power on the port(s) with lowest priority.
12.1.2.1 Calculating available power, and per-port power limitation
As of WeOS v4.17.0, PoE power is always allocated to handle max consumption
by all admitted PoE units. For each port, the max consumption (P
por t,m
) is
calculated as the minimum value of:
❼ (P
css,oc
): The power allocated to units of the attached class (see right
column of table 12.1 ).
❼ (P
por t −mt
): The power limit configured for the port (if any).
The available power is calculated as max output power of the switch 1 , minus the
sum the max power for all (admitted) ports.
P
be
= P
stch,m
−
dmtted
P
por t,m
If a new PoE unit is attached, its P
css,oc
will be compared to P
be
:
❼ If there is enough power available to serve the new unit, it will be admitted.
❼ If there is not enough power available to serve the new unit, the switch will
deliver power to the ports with highest priority (see below). Thus, to admit
the new unit, one (or more) of the already admitted units will be declined
power.
1 To compensate for limited accuracy in measured power consumption, your WeOS PoE unit may
allow the measured and allocated power to raise somewhat above the stated P
stch,m
of the
product, before power delivery is stopped/refused on some port. The customer should still ensure
that PoE equipment attached to the WeOS PoE switch do not use more than P
stch,m
in total.
➞ 2015 Westermo Teleindustri AB 257