Measurement Data; Polling; Unbuffered Reporting - Camille Bauer SINEAX CAM IEC 61850 Instructions D'installation

4. Measurement data

4.1 Polling

As for traditional transmission protocols, also for the IEC61850 communication measurement values can be
queried individually or in groups (so called Polling). The superior system initiates such a communication.
The measurements are updated only if the individual threshold (dead-band), which can be set for each value, has
been exceeded since the last query. Otherwise 'old' measurement data is transferred, which may be recognized
by the associated time stamp.
Further information about dead-bands and their modification by means of webpage or ICD file are
described in the chapter 3.4 of the document "CAM61850.PAR-E.V1.0.110215.PDF" on the CD.

4.2 Unbuffered Reporting

Each node provides reports. If such reports have been activated and at least one of the included measurements
exceeds the dead-band, the entire report with all measurements is spontaneously sent to the client. So the report
will always consist of all values of a report. A reduction is possible by deleting individual measurements from the
report control block only.
Removing measurements from reports is shown in "CAM61850.PAR-E.V1.0.110215.PDF" (chapter
3.3) on the CD.
Because data is sent subsequent to a changing only the amount of data sent will be limited. This may reduce the
processor load of the control system.
The measurement data sent with the report are updated only if the respective measurement values have
exceeded the corresponding dead-bands since the last report. Otherwise 'old' measurement data is transferred,
which may be recognized by the associated time stamp.
Further information about dead-bands and their modification by means of webpage or ICD file are
described in the chapter 3.4 of the document "CAM61850.PAR-E.V1.0.110215.PDF" on the CD.
Not in every case this is the desired behavior, as e.g. for the node MSTA (see 3.6), where always the most
present values of the past interval are required to build the statistics.
Reporting behavior
If a report is enabled its behavior may be forced by the control system. Using the parameter TrgOps you can
define under which conditions a report will be sent. One of the possibilities is e.g. to activate an integrity report.
When starting the reporting an integrity interval (IntgPd) is sent, which defines after which time without event
triggered reporting a present report will be sent from the server to the client to assure integrity. This way minimum
data traffic is performed and therefore the connection is not closed by client or server.
When setting the integrity interval you have to take care that it is harmonized to the TCP keep-alive time. This
service is described in chapter 2.4.10 of "CAM61850.PAR-E.V1.0.110215.PDF" on the CD.
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