The IEC 60870-5-104 data objects begin producing change events if the corresponding source IEC 61850 data objects reside in an IEC 61850 data set which is enabled for change reporting. Only the IEC 61850 data objects which reside in a data set are checked for value changes by the system.
Not all IEC 61850 data objects reside in data sets by default and not all data sets are enabled for reporting by default. The IEC 60870-5-104 protocol stack automatically checks the internal change reporting situation for all the single-point and double-point objects. If needed, the objects are assigned to an internal (hidden) data set. However, for measurand objects, the change reporting situation should be checked using Dataset editor in PCM600.
- The IEC 60870-5-104 data objects are selected and located in the address space using IEC 60870-5-104 Communication Management.
- In Communication Management, the data objects’ Event Enable and Interrogation Group default settings are updated if necessary. If only general interrogation (GI) is performed, the point can be assigned to any interrogation group.
- The corresponding IEC 61850 data objects are checked using Dataset editor. It must be ensured that the corresponding objects are located in a data set which is enabled for reporting.
An IEC 60870-5-104 data object works to some extent even if the object does not reside in a data set, or if it resides in a data set which is not enabled for reporting. In such a case, the IEC 60850-5-104 protocol does an internal, periodical polling of the native IEC 61850 value. If data object changes are noticed, the protocol reports them. However, this internal protocol polling cycle is slow, and thus value change updates are also slow.