In the second bullet where the IED name is defined:
- The length of the IED Name shall be at least one, at maximum 64 characters. ... Note that there might be more restrictions ...
Then from the 5th bullet defining the LDevice:
- The length of the logical device name (either ldName, or IED name concatenated with inst) is restricted to 64 characters ...
when not using a specified ldName value, the IED Name could never really have a length of 64 characters..
Currently, system configurator need to validate for each IED name length based on the current max length of ldInst within that IED. This doesn't account for additional ldInst which could be added by an ICT that could render a configured IED name invalid when changing the IED modeling (adding a ldInst with a longer name).
Furthermore, the current test procedure test case sMdl19 specify that the IED name shall be
configurable to result in a 64 characters ldName. I could not really find from where this requirement comes from.
Proposal
In order to simplify the interaction between the IED Name and ldName, it would be useful to set a limit for an IED regarding ldInst length along with IED Name length.
Having a IED property called ldInstNameMaxLength or iedNameMaxLength would simplify configuration and avoid rendering IED name invalid in case we change the modeling of an IED.
It would also simplify testing and validation of these field in SCTs and ICTs.