Subject: Re: [eman] eman framework issue: How to model a meter?
From: Juergen Quittek <[email-masked]>
To: Brad Schoening <[email-masked]>
Cc: eman mailing list <[email-masked]>
Date: Fri, 30 Aug 2013 19:43:19 +0200
List-Id: Discussions about the Energy Management Working Group <eman.ietf.org>

Hi Brad,

Thank you for the explanation. So, do I understand correctly that if you measure power you do not meteri, but if you measure energy you are?

Thanks,
    Juergen 

Am 27.08.2013 um 16:23 schrieb Brad Schoening <[email-masked]>:

> Juergen,
> 
> Metering is generally used when there is a continuos flow with the amount totalized.  Metering is usually facilitated by the presence of a physical meter which may have to meet regulatory requirements.  In the US, electric meters are divided into "Revenue Grade" and "Non-Revenue Grade" classes.
> 
> This is a noteworthy point, as an electrical device such as a PoE switch may be able to measure its instantaneous energy consumption, but typically doesn't have the ability to meter it and totalized it over time periods.
> 
> Regards,
> 
> Brad
> 
> From: Juergen Quittek <[email-masked]>
> Date: Tue, 27 Aug 2013 02:09:02 -0700
> To: "John Parello (jparello)" <[email-masked]>
> Cc: eman mailing list <[email-masked]>
> Subject: Re: [eman] eman framework issue: How to model a meter?
> 
> Dear all,
> 
> Unfortunately, I am not a native speaker. Can someone explain to me the exact difference between 'metering' and 'measuring'?
> 
> Thanks,
>     Juergen
> 
> Am 20.08.2013 um 12:17 schrieb "John Parello (jparello)" <[email-masked]>:
> 
>> Good catch let's change "perform metering" to "perform measuring" then yes go with simple.
>> 
>> So broad categorization of the device/component and continue to leave complex capability modeling out.
>> 
>> Jp
>> 
>> Sent from my iPad 
>> (expect ridiculous spelling mistakes) 
>> 
>> On Aug 20, 2013, at 11:44 AM, "Bruce Nordman" <[email-masked]> wrote:
>> 
>>> The current draft of the EMAN framework says:
>>>   "A meter is a type Energy Object and any Energy Object can perform metering."
>>> 
>>> This seems to indicate that devices can meter, components can meter, and power
>>> interfaces can meter.  On the other hand, Juergen notes that the meter classification
>>> is not available to power interfaces.  This appears to be a contradiction.
>>> 
>>> It is possible to require declaring a "primary function" for a device, including whether it is a
>>> device that can only perform metering, but that seems to be an unnecessary complication
>>> and not derivative of any requirement.
>>> 
>>> Juergen's point is that metering (or measuring--I defer on that choice of wording) can be
>>> simply and flexibly modeled as just a capability that any EO can have.  It is unnecessary
>>> to make the Framework more complicated than that.  There are plenty of additional
>>> complications that could be added that don't derive from any requirement.
>>> 
>>> --Bruce
>>> 
>>> 
>>> 
>>> On Tue, Aug 20, 2013 at 10:51 AM, John Parello (jparello) <[email-masked]> wrote:
>>>> 
>>>> <snip>
>>>> 
>>>> >
>>>> > You ask "Do we need to model metering capability at all"?  Yes, because
>>>> > smart meters, in particular sub-meters, are a key part of real time energy
>>>> > monitoring.
>>>> >
>>>> 
>>>> Just to be clear we used "meter" is a type of device (which acknowledges you other points, and if you want to model capability the value would be "measuring". So a "metering capability" doesn't make sense. It would be "measuring capability".
>>>> 
>>>> Again we removed the capabilities attribute.
>>>> 
>>>> After quite some years deploying these systems that distinction is second  nature for me but we should be precise.
>>>> 
>>>> Jp
>>>> 
>>>> 
>>>> 
>>>> > Regards,
>>>> >
>>>> > Brad
>>>> >
>>>> > On 8/20/13 1:09 AM, "Juergen Quittek" <[email-masked]> wrote:
>>>> >
>>>> >> Dear all,
>>>> >>
>>>> >> Here is another framework issue: How to model metering capabilities of
>>>> >> devices?
>>>> >>
>>>> >> Our framework draft (draft-ietf-eman-framework-08) models metering
>>>> >> capability by categorizing devices and components into either a producer,
>>>> >> a comsumer, a meter, or a distributor, see pseudocode on page 43.
>>>> >>
>>>> >> I think this approach is broken. It may be useful for modeling simple
>>>> >> scenarios, but it does not work as general model.
>>>> >>
>>>> >> There are two problems with this approach.
>>>> >>
>>>> >> 1. The either-or classification. A meter is typically not just a meter,
>>>> >> but as well a consumer that consumes energy when doing it's job. A PDU
>>>> >> that meters power at it's outlets is a meter and a distributor and a
>>>> >> consumer. The same holds for a PoE switch. These are not either meters or
>>>> >> consumers, they are meters and consumers and some of them are also
>>>> >> distributors at the same time.
>>>> >>
>>>> >> 2. The categorization as 'meter' is only available for devices and
>>>> >> components, not for power interfaces. But obviously a device with
>>>> >> metering capabilities meters at (some of) its interfaces. Take the PoE
>>>> >> switch that meters power at some or all of its PoE outlets. It would be
>>>> >> natural to label the power interfaces at which metering capabilities are
>>>> >> available as 'metered'. It appears strange to classify the device as
>>>> >> 'meter'.
>>>> >>
>>>> >> The basic question here is: Do we need to model metering capability at
>>>> >> all?  If yes, we should model it as an attribute, not as a category; and
>>>> >> we should model it as attribute of the power interfaces as well.
>>>> >>
>>>> >> BTW, if we model metering capability (monitoring), we should consequently
>>>> >> model circuit breaker capability (control) at power interfaces as well.
>>>> >>
>>>> >> Cheers,
>>>> >>  Juergen
>>>> >> _______________________________________________
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>>>> >> https://www.ietf.org/mailman/listinfo/eman
>>>> >
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>>> 
>>> 
>>> 
>>> -- 
>>> Bruce Nordman
>>> Lawrence Berkeley National Laboratory
>>> nordman.lbl.gov
>>> [email-masked]
>>> 510-486-7089
>>> m: 510-501-7943
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