The part 7-1 Ed2 defines: "Standardised data names in logical nodes provide a unique identification. If the same data (i.e. data with the
same semantics) are needed several times as defined, additional data with number extensions shall be used."
This may be used for several Channel numbers in LN RBDR: ChNum1 ING
Several data objects with index 1 can be found, e.g., in the LN GGIO: AnIn1 MV Analogue input
You may define AnIn1 for temperature, AnIn2 for pressure, AnIn3 for whatever, ...
These data objects have DIFFERENT semantics! So, the rule in 14.6 are not applicable for the G LN Group - because the rule is for data objects with the SAME semantic.
AnIn does not have a semantic - just a type and an index.
Proposal
Add exception:
"Standardised data names in logical nodes provide a unique identification. If the same data (i.e. data with the
same semantics or the same common data class) are needed several times as defined, additional data with number extensions shall be used.
Note - Data objects with the same semantic can be found, e.g., in LN RBDR; data objects with the common data class can be found, e.g., in GGIO and other general logical nodes."
Discussion
Created
Status
23 Mar 12
Not Applicable
The new UML model uses constraints at the LN class level to describe the rule for multiple data instances and 7-1 will need to be adapted accordingly in Ed. 3. No change for the moment.
27 Feb 12
Discussion (red)
Note also that it is not allowed to use the index in case where the data object name does not have an index 1 in the standard.
An example that I found is discussed here:
http://blog.iec61850.com/2012/01/how-to-define-new-data-objects-in-iec.html