The real benefit of using a function specific logical node (e.g.
PDIF etc) is that the LN conveys a lot of semantic information.
If you use
GGIO you need to maintain a parallel set of document that describe the purpose of each
GGIO. This is really no benefit over DNP3 or Modbus points. If I am subscribing to messages then I know that I have the transduced power (MW) value when I connect
PriFouMMXU1.MX.TotW. An analogue
GGIO simply doesn’t do this.
Which has more meaning:
BOUT_GGIO1.ST.Ind.stVal? I can tell immediately that I've connected the transformer differential trip with the 'proper' LN without needing to refer to anything else. The devices don't care what is subscribed to in the SCD file, but it sure helps reduce the chance of the human making a mistake.
These data attributes come from a real IEC 61860 system. The only reason I used
GGIO for outputs is that they came from an RTDS that treats GOOSE output as a binary output card. The IEDs all supported 'real' LNs in their published GOOSE datasets. Making sure I had the right
GGIO when setting up IED subscriptions was a pain in the neck—setting up the RTDS subscriptions was very easy by comparison.
IEC 61850 is all about systems, not simply communications between devices.