1470 Default value for operational process values.
Created: 14 Jan 2016
Status: Not Applicable
Part: Part 6 (2009-12; Edition 2)
Clause: 9.5.4 Data attribute (DA) definition
Paragraph: Table 46 – Attribute value kind (Valkind) meaning
Category: No impact on this part
As discussed in issue 670, there is no way to set a default value for mod DO, in that case the value 'off ' to disable the LN. They are proposing the creation of a new DO called setMod which can be used to define the initial state of that operational value. This could be applied to any other operational value, for example the Sim DO in LPHD.
I disagree about the creation of a new DO for every operational process startup value that we need to set at configuration time. I think we can use the attribute valKind='Set' in SCL to define such behavior.
Additionally we should make the table 46 more clear by adding the MMS behavior of the value. It's confusing that an DA with valKind='Set' for ST fc is RO at MMS (see table Table B.1 of 7-3ed2), but for CF or DC is writable.
Add another column to table 46 to explicit the run time behavior (RO, RW or Hide), or we should make an annex to detail the right usage of valKind attribute.
Mod is a special case, as you might want to enable / disable protection functions in different setting group value sets. Therefore the suggested SetMod:SPG as member of a setting group is needed, i.e. this Tissue does not touch 670.
In general, as described in the issue, part 6 SCL syntax allows already for special cases like testing, simulation, default value at start-up or process acquisition fault etc. to use a specified SCL value also for process data. However, as only one value can be specified and all these special functions are outside the scope of a communication standard, it is an IED / manufacturer specific issue if and how this feature is used. Therefore a system engineer cannot in general rely on this feature e.g. to set a Mod default (start-up) in an IED, and a system tool might refuse to do this because the purpose is not known to it.
Further, it is not accepted to add service related definitions into part 6, as this makes maintenance of the standard too complex.
Summary: Part 6 allows this already as IED specific feature. However, as many applications for this are possible, this is not standardized but needs to be defined specifically for an IED, and will typically be used by the IED tool. No change to part 6.
|20 Jan 16
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