Saturday, February 14, 2015

VHPready Signal MMXU1.TotW.instMag – versus IOA 113

Signals configured in IEC 61850 and configured in IEC 60870-5-104 look quite different.

The following figure shows the same signal (Current electric Power – Aktuell erzeugte elektrische Leistung) in IEC 61850 (left) and IEC 60870-5-104 (right):


The IEC 61850 model exposes the value, quaity and timestamp as well as the semantic (TotalWatt). The total watt of what? Of the “Current electric Power – Aktuell erzeigte elektrische Leistung” as described in the DC (description of the signal).

On the other side we have the information object address (IOA = 113) that carries the same value in IEC 60870-5-104. What does the value 3456 mean? No idea in IEC 60870-5-104. You have to know upfront what 113 means. IEC 61850 stores the meaning in the device (model).

In the above case we see also the IOA=113 in the description (DC) of the IEC 61850 model. It is a text string attached to the DC attribute.

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