this is not what I meant.
best way in my opinion to discuss about technical solution
is to sketch a complete solution i.e. present a solution
that starts from simple high level requirements such:
that is not depend on implementation.
requirement (current or resistance or else) is one number,
worst case, specified in the UUT operating state/range
be described by solid mathematical _expression_ or other
try to show one example for PSE if I'll have time for
Thursday meeting. If not, we will have time on IEEE week.
consider the following EXAMPLE:
case #1: PD is single load. (we need to check other use
cases and generate set of requirements that doesn’t
contradict each other. It is possible if we replace ideas
with mathematical expressions so we can plug there physical
limitations, backward compatibility considerations that can
be described by numbers etc.)
is brought to ON state
operating input voltage is 36 to 57.
min- max total load current (Itotal) is 10mA to TBD
specification will say the worst case PD PI Pair to Pair DC
input resistance is e.g. 15%. (please note that in single
load PD, Iunb=P2PRUNB*Itotal.
is the responsibility of the PD vendor to make sure that he
doesn’t cross his P2PRUNB no matter where this point is on
his P2PRUNB curve so it doesn't matter if it is linear curve
or other .
THE PD PI P2PRUNB is number that is derived from End to
End Channel Resistance number that we define what we want
it to be to optimize
of the entire system component. Same PSE PI P2PRUNB.
continue until there is clear solution. I guess we all know
what we want. We just need to bring complete solution so we
can discuss it.
try to follow this concept and see if I can have something
solid for discussion.
We can discuss the points of disagreement as you indicate.
One initial point I'd like to point out is the following:
(From the slide:)
PD PI Runbalance testing
Has a time-varying load, so Sequential measurements
won’t work universally unless special operating modes or
internal probing is included
Yair: (Disagree. When power on,
look for DC behavior ,or specify DC behavior)
Ken: If the first step of an PD PI Runbalance test is
to require a DC load behavior, you have already crossed a
boundary forcing PD designers to implement a special operating
mode that may not otherwise exist. If testing worst case,
then the DC mode has to be at full power, and full power
without a varying load may not even be possible.
On 5/7/2014 3:45 PM, Darshan, Yair wrote:
Thanks. See my comments up to page 5 due to lake of time.
We can discuss more at the IEEE meeting.
From: Ken Bennett [mailto:ken_bennett@xxxxxxxxx]
Sent: Wednesday, May 07, 2014 8:42 PM
Subject: [802.3_4PPOE] Fwd: Re: [802.3_4PPOE] IEEE802.3bt End to End Channel Pair to Pair Resistance Unbalance - Meeting material for Thursday May 8, 2014 meeting.
I've attached some slides relating to the Runbalance PI Specification.
Comments are welcome.