With V3.0, EnergyPlus will automatically expand. But
won't be able to be run in the IDF editor.
How to expand the IDD is discussed in several places in the
Documentation. And the documentation is searchable in
Acrobat.
Specifically, in the IDD, it is explained as well:
! \extensible:<#> This object is dynamically extensible
-- meaning, if you
! change the
IDD appropriately (if the object has a simple list
! structure
-- just add items to the list arguments (i.e. BRANCH
! LIST).
These will be automatically redimensioned and used during
! the
simulation. <#> should be entered by the developer to signify
! how many of
the last fields are needed to be extended (and EnergyPlus
! will
attempt to auto-extend the object).
as an example:
AirLoopHVAC:ZoneSplitter,
\extensible:1 Just duplicate last
field and \ comments (changing numbering, please)
meaning, take the last field, and copy/paste it. replace the ; with
, for all but the last field.