1639   Names of instantiable data

Created: 22 Nov 2018

Status: Not Applicable

Part: Part 7-1 (2011; Edition 2)

Links:

Page:

Clause: 14.6

Paragraph: Specialisation of data by use of number extensions

Category: Issue for edition 2 of this part

Issue

The clause concerns standardised data names in logical nodes to assure unique identification also in case when multiple instances of the same data object are required in LN. It is demanded that if only one instance of an extendable data is present in an LN, it shall have the number extension “1”. In Part 7-4 Edition 2 the names of instantiable data objects within LN classes are indeed extended with "1". Though, in Part 7-1 Ed.2-1 CDV the names of instantiable data are not extended but information of possible instantiation is given in PresCond column as Mmulti or Omulti. But Part 7-1 AMD1 Ed.2 CDV in Clause 14.8 still insists that even if only one instance of an extendable data is present in an LN, it shall have a number extension (but not necessarily "1").
This situation leads to the necessity of reconfiguring all data flows to client systems for all extendable data appearing in one instance in case of the server device software upgrade. For example, a reported Ind data object from GGIO LN Ed.1 will have to be received as Ind1 data from GGIO LN Ed.2, while it can be received as Ind5 data from GGIO LN Ed.2-1.
Data object name extension in case of single instance of this data within LN gives no added value. In the described case the goal of precisely specifing which data objects are extendable (instantiable) and which are not led quite unnecessarily to enforced renaming of data. And this has probably a very unwanted impact on retaining the defined data flows to client systems.
No doubt, the existing client systems certainly tolerate single instances of data with names not extended by "1" as a natural inheritance of the names allowed in Ed.1.

Proposal

Change the text in Part 7-1 (2011; Edition 2) clause 14.6 from:
– if only one instance of an extendable data is present in an LN, it shall have the number
extension “1”.
to:
– if only one instance of an extendable data is present in an LN, it shall have the number extension “1” or no extension.
Respectively, change the text in Part 7-1 AMD1 Ed.2 clause 14.8 from:
- even if only one instance of an extendable data is present in an LN, it shall have a number extension.
to:
- if only one instance of an extendable data is present in an LN, it may have no number extension.