Clarification request concerning the use of the 'PowerRampSegmentType' in EMIX 1.0

[Jerald.P.Martocci@jci.com]

Specification Reference:

EMIX 1.0     13.6.1 Power
Ramp Segments


Background:

The SPC201P FSGIM standard extensively
references EMIX.  During a FSGIM review cycle, a comment was received
requesting that the FSGIM data structure defined for describing ramping
demand (DPieceWiseLinear) be replaced with the analogous EMIX ramping construct.
 This construction appears to be PowerRampSegmentType as shown below
immediately followed by the UML description.

The UML model reads:

where:

rate - the
power component of a ratio specifying the maximum rate of change of power
for this segment.
duration - the
time period component of a ratio specifying the maximum rate of change
of power for this segment.
beginRamp - Quantity
of power at the start of a ramp segment.
endRamp - Quantity
of power at the end of a ramp segment.
integralOnly - If true, offer is all or
none; no partial acceptance of this segment.



Items Needing Clarification:


There are several questions concerning
this construction:

1) The definition of the 'rate' attribute
differs (or appears to differ) between the text and UML versions of the
model.  The text seems to indicate that the 'rate' describes the units
of the line segment; the UML model indicates it defines the slope of the
line segment.  The actual data type construct seems to define both
in 'powerItem' and 'quality' attributes respectively.  

The question is,  "What is
'rate' used for?"  Is it supposed to represent (End Ramp Power
- Begin Ramp Power)or the units for those power quantities?  If it's
the former, then please change the Note in the documentary specification
to say that (and possibly change the name of the element to better indicate
it).  If it's the latter, then please change the name of the Element
to "Unit" and its type in the schema to PowerItemType.

2) The line segment slope is given by
either the algorithm [(endRamp - beginRamp)/duration] or by the rate.quantity
attribute directly.  It seems redundant to have multiple attributes
defining the same value.

3) beginRamp and endRamp are typed as
'integer'.  I would expect that these attributes would be at least
typed as 'float'.  Better yet, I would expect they would be typed
to handle real and apparent power values.

4) The PowerItem attribute is defined
for each line segment of the ramping curve thereby requiring each line
segment to describe an 'item description',  'item units, 'siScaleCode',
hertz, voltage and AC.  It seems this meta data should be promoted
up a level so it is defined one time for the entire ramping curve.  Furthermore,
there are no multiplicities defined for this meta data.  Is this implicitly
noting these are required attributes (i.e. [1..1]) or does EMIX not define
multiplicities across the specification?



If you can provide insight to these
questions, I would like to use this construct in the SPC201P model.


Regards,

Jerry Martocci