PowerSync Service Analyzer Reference Manual
February 8, 2010
Sifos Technologies page
27
3.3.
PoE Scope Trace
Another unique feature of the Sifos
PoE Service Analyzer
is the ability to produce
graphical waveforms
of controlled
PoE events. These waveforms can be useful for observing problem behaviors.
Two
Power-Cycle
waveforms are included to observe the full cycle of an ordinary PoE power-up and PD disconnect
power-down captured over a 5 second time interval. One waveform looks at line voltage (
see Figure 3.9
) while the other
records electrical current flow (
see Figure 3.10
). Both can be configured to run with PD
Class 1
,
Class 2
, or
Class 3
emulation. Users with very moderate understanding of PoE technology can observe and analyze
detection signaling
,
classification signaling
, the
powered line state
, and PSE response to a
PD disconnect
.
Two additional waveforms available are
Disconnect Shutdown
(
see Figure 3.11
) and
Overload Shutdown
(
see Figure
3.12
). These waveforms may utilized to visualize the PD service outlet response to either a PD disconnect or a PD
transient overload condition. Both conditions should result in power removal in order to prevent damage to network
devices when plugged into the service outlet. The disconnect shutdown should occur in approximately a half second while
the overload shutdown should occur in less than one tenth of a second, regardless of PD Classification selected.
Following waveform capture, waveforms may be printed or imported to Microsoft Excel for further analysis as shown in
Figure 3.13.
Figure 3.9
:
Power Up/Down Voltage Cycle
Figure 3.10
:
Power Up/Down Current Cycle
Figure 3.11
:
Overload Shutdown Voltage
Figure 3.12
:
Disconnect Shutdown Voltage
Figure 3.13
Voltage Cycle Waveform - Excel