3.3 Value change detection
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.
3.3.1 IEC104 protocol cyclic reporting
The IEC 61850 measurands are internally reported to the IEC 60870-5-104
protocolaccording to the rules stated in section
Chapter 3.8.4 Update rate of analog
and indication protocol data
. The IEC 60870-5-104 protocol has also a dedicated
setting for its own cyclic transmission in Configuration> Communication>
Protocols> IEC 60870-5-101/104 (n)> Cyclical Period. This cyclical period interval
is not synchronized with the actual update rate of the measurement values, but
only defines the sending rate of the cyclical reports. For adjusting the actual update
rate of the analog value refer to chapter
Chapter 3.8.4 Update rate of analog and
indication protocol data
.
3.3.2 IEC 60870-5-104 data object configuration
1. The IEC 60870-5-104 data objects are selected and located in the address space
using IEC 60870-5-104 Communication Management.
2. In Communication Management, the data objects’
Event enable
and
Interrogation
default settings are updated if necessary. If only general
interrogation (GI) is performed, the point can be assigned to any interrogation
group.
3. 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.
2NGA001859 A
Vendor-specific implementation
REX615
IEC 60870-5-104 Communication Protocol Manual
19
To Next Page
Loading...
