Re: [802.3_4PPOE] Regarding the transient below 30usec.

[Lennart Yseboodt <lennartyseboodt@xxxxxxxxx>]

Hi Yair,

Making a new paragraph does absolutely nothing to the requirements.

If anything, those 3 sentences all deal with the same topic: transients of various lengths, and should be one paragraph.

We're past the point we should be making such changes.

I've the feeling there is a subsurface misunderstanding happening, there is no other explanation for so many emails over this topic.

Here's what 145.2.10.3 REQUIRES:

(1) Transient of longer than 250uS ==> voltage SHALL meet VPort_PSE-2P for the entire duration of the transient

(2) Transient of 30-250uS ==> voltage SHALL not go below VTran-2P at any time

(3) Transient of 30us or less ==> voltage MAY fall below VTran-2P

I list (3) even though it is not a requirement.

All this statement does is reinforce that we specifically choose not to make any requirement on the PSE for this particular case.

There is nothing broken here, hence the resistance to make changes.

I would suggest we don't make any changes here.

Kind regards,

Lennart

On Thu, 2018-06-14 at 18:23 +0000, Yair Darshan wrote:

Hi Chad,

 

I thought about this comment and I am proposing simpler solution that in my opinion will be good enough.

Currently the text looks like this:

 

β??A PSE shall maintain an output voltage no less than VTran-2P for transient conditions lasting more than 30 ΞΌs and less than 250 ΞΌs, and meet the requirements of 145.2.10.9.

[SPACE]

Transients less than 30 ΞΌs in duration may cause the voltage at the PI to fall below VTran-2P. See 145.3.8.6 for PD transient requirements. Transients lasting more than 250 ΞΌs shall meet the VPort_PSE-2P specification.β??

 

The problem is if I read the above text:

I see a clear requirement on the first paragraph addressing the requirements for 30usec-250usec.

The second paragraph starts with informative text regarding transients below 30usec that invite the question β??OK what to do with it, what is the requirementβ?? and then you have again a clear requirement for behavior above 250usec.

 

If I make small editing change such as follows (append both paragraphs):

 

β??A PSE shall maintain an output voltage no less than VTran-2P for transient conditions lasting more than 30 ΞΌs and less than 250 ΞΌs, and meet the requirements of 145.2.10.9. Transients less than 30 ΞΌs in duration may cause the voltage at the PI to fall below VTran-2P. See 145.3.8.6 for PD transient requirements. Transients lasting more than 250 ΞΌs shall meet the VPort_PSE-2P specification.β??

 

Now if I read this:

I see 1^st requirement. Clear informative part. 2^nd requirement.

 

What is your inputs on this proposal?

Does it make sense that it is simple change just remove space and merge both paragraphs so it will not look like two different paragraphs that the 2^nd one starts new requirement which is not the intent.

 

Yair

 

 

 

 

 

Darshan Yair

Chief R&D Engineer

Analog Mixed Signal Group

Microsemi Corporation

 

1 Hanagar St., P.O. Box 7220
Neve Ne'eman Industrial Zone
Hod Hasharon 45421, Israel
Tel:  +972-9-775-5100, EXT 210.

Cell: +972-54-4893019
Fax: +972-9-775-5111

 

E-mail: <mailto:ydarshan@xxxxxxxxxxxxx>.  

 

 

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