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1MRK 511 391-UUS A
3.5.3
3.6
670 series 2.2 ANSI
Communication protocol manual
ctlModel, of the SCSWI is respected when set to SBO Enh. If ctlModel is set to SBO
Enh, direct operate commands from DNP3 are not allowed. On the other hand, if
ctlModel is set to Dir Norm, SBO commands from DNP3 are allowed.
Furthermore, the select timeout parameter tSelectTimeout in DNP3 should be set so
that it harmonizes with the tSelect parameter of the SCSWI. The shortest of the two
parameters dictates the timing of select/execute.
Binary output status points and control relay output blocks
While binary outputs status (BOS) points are included here for completeness, they are
not often polled by DNP3 masters. BOS points represent the most recent value from a
command operation for the corresponding control relay output block (CROB) point.
BOS points are not recommended to be included in class 0 polls.
As an alternative, it is recommended that actual status values affected by CROB points
should be mapped as BI or DI. Requesting CROBs on the Open and Close points of
SCSWI operate the breaker. The operation may take several seconds to complete. This
means that a success response from the operate command may have been returned
from the CROB even though the operation is still in progress. Therefore, the mentioned
outputs from, for example, SCSWI need to be monitored as a complement.
This implies that the binary output object should not be assigned to classes 1, 2 or 3. A
read of the binary outputs returns the last value written to that output.
Time synchronization
DNP3 supports time synchronization of the IED via object numbers 50...52. Time
synchronization via DNP3 should only be used if time source with better accuracy is
not available, for example, IRIG-B, GPS or SNTP. For TCP/IP channels, the LAN
procedure should be used, in which two separate messages are transmitted from the
master, record current time and write, see DNP3 Specification Volume 5 for more
information.
Parameters have to be set among the system wide time parameters as
well as among the individual DNP3 masters.
DNP3 can be set for a coarse synchronization source under Configuration/Time/
Synchronisation/TIMESYNCHGEN:1/CoarseSyncSrc in the LHMI tree. Note that
when DNP3 is set as coarse synchronization source, no fine synchronization source
shall be configured. Otherwise, the time will jump between the fine and the coarse
synchronization time sources.
Vendor-specific implementation
GUID-226B14A8-63D2-4CE3-9B44-ACB3B1F783B9 v2
GUID-A64325B9-381F-48A3-8130-8A17EE0C1C80 v4
Section 3
19
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