Lennart – the second paragraph has a defect. Not sure which one I prefer yet.
“The PSE either uses the legacy power up method, whereby it limits the inrush current to IInrush
until the PD input voltage
reaches 99% of steady state, or it limits the inrush current for a fixed amount of time, TInrush,
as defined in Table 33–11.
See ‘legacy powerup’ in 33.2.4.4”
It limits the inrush current TO WHAT for a fixed amount of time, TInrush.
I think you mean
“The PSE either uses the legacy power up method, whereby it limits the inrush current to IInrush
until the PD input voltage
reaches 99% of steady state, or it limits the inrush current
to IInrush
for a fixed amount of time, TInrush, as defined in
Table 33–11.
See ‘legacy powerup’ in 33.2.4.4”
Also, I’d probably reword it to be clearer about legacy power up: (and aren’t these both requirements – if show, change “limits” to “shall limit” – if not, they must be covered by a general shall on the table?)
“If using the legacy power up method (see 33.2.4.4), the PSE limits the inrush current to IInrush
until the PD input voltage reaches 99% of steady state.
When not using the legacy power up method the PSE limits the inrush current
to IInrush
for a fixed amount of time, TInrush, as defined in
Table 33–11.”
This last one is my preference.
Thanks for winnowing it down to something clear.
-george
From: Lennart Yseboodt <00000b30a2081bcd-dmarc-request@xxxxxxxx>
Sent: Thursday, November 01, 2018 1:45 PM
To: STDS-802-3-MAINT@xxxxxxxxxxxxxxxxx
Subject: [STDS-802-3-MAINT] [v120] Re: 802.3cq - inrush baseline v110
Please find a new version of the baseline.
It was brought to my attention that our new inrush rules actually relax the inrush requirement in a particular case.
When a PSE assigns Class 4, per the current text and state diagram, the PD must obey a Class 3 power limit until Tdelay.
Our new section relaxes that to drawing less than 400mA. Ultimately we need both of these requirements.
The new version v120 adds a new requirement (last sentence) to address this.
I've also added the original subclause for reference.
On Tue, 2018-10-23 at 22:47 +0200, Lennart Yseboodt wrote:
Attached updated text for the PD inrush section as discussed on the last adhoc.
I put in two variants for the informative piece of text describing PSE inrush behavior. At the next adhoc call let's pick one of these.
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