Sifos Technologies PowerSync PSA100, Техническое справочное руководство

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PowerSync Analyzer Reference Manual
March 9, 2010 Sifos Technologies page 40
voltage values, pre-detection measurements, and invalid signature responses. Legacy detection pulses can also be
observed in this waveform for certain PSE’s.
Classification
: This waveform focuses on the classification pulse showing either voltage or current. Current level will
of course be affected by the
Classification Load
setting. All signaling aside from classification will be removed.
Power-Up Sequence
: This waveform is available in two forms, 802.3af
Standard
power-up and
Legacy
mode power-
up. The
Standard
waveform captures the Detection, Classification, and Power-On waveforms during an 802.3af
power-up sequence, thus emulating a PD connection. The
Voltage
mode will show the detection pulse, classification
pulse, and power-up voltage levels along with various waveform transitions leading to power-up. The
Current
mode
will show the classification load current and the in-rush and steady-state load currents implemented by the PSA test
port. The
Legacy
mode will attempt to get the PSE to power up with a capacitive load in excess of 50
μ
F (or 11
μ
F for
Type 1 PSA blades). Since there are no standards for legacy detection, there is no assurance that the PSE will apply
power, though from experience, many PSE’s with hybrid-legacy capability will power up given this detection load.
Load Response
: Two waveforms are available for viewing the powered up response to a varying DC load. With the
Slow Load
waveform a slowly changing load current waveform is applied to the PSE port. The range of the load
waveform is affected by the
Classification Load
setting with a load waveform varying from 10% to 130% of the
nominal load for that classification. The waveform may be viewed as actual load current in
Current
mode or the
voltage impact of this waveform can be observed in
Voltage
mode.
The Fast Load
waveform is captured during a
more rapid load excursion applied between 50% and 150% of nominal load current for the selected Classification Load
setting. The actual load current waveform is viewable in the
Current
mode and the impact of this load on voltage is
visible in the
Voltage
mode.
Load Compliance
: Load compliance generally refers to the
PSE port’s current and power limiting capability under
conditions of high load from a PD. 802.3af specifies current
limits under conditions of start-up (or
Inrush Load
) and
Short Circuit (Figure 3.22)
. The
Inrush Load
waveform
enables viewing of both current limit and voltage response
during a power-up event. The
Short Circuit
waveform
applies the short circuit overload well after the port is
powered at the nominal PD classification level and enables
viewing of the current limit, voltage response, and shutdown
timing.
Shutdown
: There are 3 shutdown waveforms that allow
viewing of various port shutdown characteristics. The
Disconnect
waveform is useful for observing disconnect
shutdown timing and any AC MPS (or other AC)
waveforms that may be present during this interval.
This waveform
(Figue 3.29)
is primarily meant to be
observed in
Voltage
mode since by definition, current
load is zero when the PD is disconnected.
The
Overload
waveform will capture either current or
voltage behavior during a PSE port overload condition
and the resultant power-down that should occur. It is
valuable for assessing power-removal timing and current
compliance characteristics. The overload magnitude is set
just above the PSE’s overload shutdown point which may be classification level dependent. It is useful for viewing
overload voltage and timing information. The
Error Delay
waveform captures PSE port behavior following an
overload shutdown. The voltage mode is useful for viewing error delay timing and any signaling that appears during
this interval.
Figure 3.22
Short Circuit Load Compliance Current
Figure 3.23
Disconnect Shutdown Voltage Waveform