Section 7
Logical node data model
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The data model used by IEC 61850 is based on logical nodes containing a set of data objects. The
data model is defined in the standards.
•
IEC 61850-7-4 Compatible logical node classes and data classes
•
IEC 61850-7-3 Common data classes
The standard describes only classes of logical nodes and data objects on one side and common data
classes for the data object attributes. Also here it is given has the elements in these classes are
defined as:
•
Mandatory (M)
•
Optional (O)
•
Conditional optional (Cxxx)
•
In addition, the IEC 61850 states rules for adding vendor-specific definitions to the standard, in
order to cope with extra functionality.
The possible description of the data model according to the standard allows to adapt a logical node
of a LN class to that what the product is supporting or using for this LN. This definition of what parts
of a class is used in the actual product and possible addition is called a type, according to IEC
61850-6. There are LN types based upon LN classes. The LN type attributes are called Data Objects
(or DATA) and are in of DO types, base upon respective CDC class. This allows all partners in the
IEC 61850 project who need this LN to understand the LN in all details for the communication part.
The IEC 61850 standard does not describe the functionality and way of operation. Each supplier has
to describe this separately. ABB has described their function blocks that represent a logical node and
all other function blocks in the technical manuals. This chapter in the communication protocol manual
has two purposes:
•
Describe the Logical Node types and their data object attribute types.
•
Make the link to the description of the function block.
7.1
Common data objects in each logical node
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The IEC 61850 standard describes in part 7-5, a Common Logical Node. The data objects contained
in that LN are both mandatory and optional. The mandatory data objects have to be included in each
LN. This clause describes the general handling of the data objects in the IEDs.
The mandatory data objects as defined in IEC 61850-7-4 as part of the Common Logical Node are
Mode, Behavior, Health and NamePlate. Mod, Health and NamePlate are mandatory only in the root
LLN0, and optional in all other LNs.
Mode
Only
On
and
Off
are supported on all LNs except for LD0/LLN0, where
On
,
Blocked
,
Test
, and
Test-
Blocked
are supported. Beh can then get all the possible values (
On
,
Blocked
,
Test
,
Test-blocked
and
Off
) as a result of Mod on the Root LLN0 and the individual LNs.
The operation modes
On
(enabled) and BLOCKED are supported remotely by a command or from
the LHMI of the service kit.
If the setting
RemoteModControl
is set to
Off
(default), all remote writes to Mod will
be rejected.
Behaviour
1MRK 511 441-UEN Rev. C
Section 7
Logical node data model
Switchgear control unit SAM600-IO
31
Communication protocol manual
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