When working on this issue, then we should check whether also other settings are standardized in the same way, requesting the same solution.
What about settings allowing either a primary value or a percentage value (e.g. 'ANCR.BndWid')?
Should a guideline for modelling settings be created?
Draft text for a guideline (by courtesy of Tom Berry):
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Defining settings for functions
Most of the logical nodes in part 7-4 follow the principle that settings are defined using absolute values, such as amps or volts. This matches the expected data acquisition with sampled value streams that also use absolute units. It is a system integration activity to ensure that such settings are consistent with the ratings defined in the relevant TVTR, TCTR or Zxxx logical nodes, which may be in the same or a different IED.
For some functions, it may suit the algorithm or user HMIs, to express settings in percentage of a nominal value. This nominal value may be defined in the same logical node or may be defined by a reference to a related logical node. For example in part 7-420, for the voltage reduction use cases, it is convenient to define settings as a percentage of the nominal voltage at a connection point. In these cases, the relevant logical nodes have settings data objects that are references to the Logical Node that holds the reference value.
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