P54x/EN SC/La4 SCADA Communications
(SC) 13-24
MiCOM P543, P544, P545 & P546
SC
4. DNP3.0 INTERFACE
4.1 DNP3.0 protocol
The descriptions given here are intended to accompany the device profile document that is
included in the Relay Menu Database, P54x/EN MD. The DNP3.0 protocol is not described
here, please refer to the documentation available from the user group. The device profile
document specifies the full details of the DNP3.0 implementation for the relay. This is the
standard format DNP3.0 document that specifies which objects, variations and qualifiers are
supported. The device profile document also specifies what data is available from the relay
via DNP3.0. The relay operates as a DNP3.0 slave and supports subset level 2 of the
protocol, plus some of the features from level 3.
The features supported are described below.
4.2 Object 1 binary inputs
Obje
ct 1, binary inputs, contains information describing the state of signals within the relay
which mostly form part of the digital data bus (DDB). In general these include the state of
the output contacts and input optos, alarm signals and protection start and trip signals. The
‘DDB number’ column in the device profile document provides the DDB numbers for the
DNP3.0 point data. These can be used to cross-reference to the DDB definition list that is
also found in the Relay Menu Database, P54x/EN MD. The binary input points can also be
read as change events via object 2 and object 60 for class 1-3 event data.
4.3 Object 10 binary outputs
Obje
ct 10, binary outputs, contains commands that can be operated via DNP3.0. As such
the points accept commands of type pulse on [null, trip, close] and latch on/off as detailed in
the device profile in the Relay Menu Database, P54x/EN MD and execute the command
once for either command. The other fields are ignored (queue, clear, trip/close, in time and
off time).
Due to that fact that many of the relay’s functions are configurable, it may be the case that
some of the object 10 commands described below are not available for operation. In the
case of a read from object 10 this will result in the point being reported as off-line and an
operate command to object 12 will generate an error response.
Examples of object 10 points that maybe reported as off-line are:
Activate setting groups - Ensure setting groups are enabled
CB trip/close - Ensure remote CB control is enabled
Reset NPS thermal - Ensure NPS thermal protection is enabled
Reset thermal O/L - Ensure thermal overload protection is enabled
Reset RTD flags - Ensure RTD Inputs is enabled
Control Inputs - Ensure control inputs are enabled
Note: There is an additional image of the Control Inputs. Described as alias
Control Inputs, they reflect the state of the Control Inputs, but with a
dynamic nature.
If the Control Input DDB signal is already SET, and a new DNP SET command is sent to
the Control Input, the Control Input DDB signal goes momentarily to RESET and then
back to SET.
If the Control Input DDB signal is already RESET, and a new DNP RESET command is
sent to that Control Input, the Control Input DDB signal goes momentarily to SET and
then back to RESET.
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