means that no keep-alive messages are sent. It is important to know the hazards of
disabling the keep-alive, and it is not recommended to do so unless necessary. If the
keep-alive messages are unwanted, it is better to increase the value of
tKeepAliveT
so
that it exceeds the master's poll rate.
If a master crashes or the communication links are broken and the master restarts, the
TCP/IP makes the IED believe that the connection still exists. Since the IED conforms
to the recommendations of the standard not to accept new connections when a
connection already exists to the particular master, the master will never be allowed to
connect again. Another parameter that concerns the TCP/IP connection status is
tBrokenConTout
. It determines how long a session is active after a TCP/IP connection
has been broken. After the time period, the session becomes inactive and events are not
stored. If the parameter is set to 0, events are stored until the sequential buffers
overflow. Note that if the parameter is set to zero, all events from start-up until the
sequential buffers overflow are saved even though no connection would have been
established.
Further documentation concerning DNP3 TCP/IP communication is available in the IP
Networking document Volume 7, from
.
3.2
DNP3 UDP-only mode
GUID-2605E868-4438-49C6-A307-1D18F8022F1F v1
DNP3 UDP-only mode is supported by the IED. When operating in UDP-only mode
the parameters
UDPPortInitNUL
and
UDPPortCliMast
must be configured.
If the parameter
UDPPortCliMast
is set to
0
the port number and master IP address is
taken from the previous request. It is important to have in mind when using this
functionality that the parameters
MasterIP-Addr
and
MasterIPNetMsk
need to be set to
values that match the network setup.
The system will only consider IP-address included in the range defined by
MasterIP-
Addr
and the
MasterIPNetMsk
as valid addresses to use then when responding.
3.3
Internal indications
GUID-2CDB2CDE-28F5-4E07-8BB7-A3537888058D v3
Internal indications give information on certain status and error conditions within the
outstation. They contain 2 octets of data and are found in the application layer on an
outstation response.
Each octet has 8 bit fields numbered 0 through 7 where bit 0 is the least significant bit.
A code is used to reference or specify a particular bit:
Section 3
1MRK 511 413-UUS B
Vendor-specific implementation
16
650 series 2.2 ANSI
Communication protocol manual
