PACiS GTW GTW/EN T/C40, Technical Manual

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GTW/EN FT/C40 Functional Description
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PACiS GTW gateway
4.2 Station bus
PACiS GTW behaves mainly as a client of other IEC 61850 devices: MiCOM Computers,
IEC 61850 IED, PACiS GTW.
Protocol:
•
IEC 61850
Link layer: Ethernet 10 or 100 Mbps
Physical support:
Copper twisted pair (RJ45 connector)
Number of communication links: one (an Ethernet rail-din switch can be used for redundancy
Ethernet network).
4.3 Loss of communication
PACiS GTW stores SBUS data changes in its kernel. It is then able to answer quickly to any
kind of query from a remote master. It is a key advantage when communication with SCADA
is subject to disconnection and reconnection (PSTN network).
PACiS GTW detects TBUS disconnection from SCADA (time out) and provides this
information on SBUS to the central archiving/logging (or other PACiS GTW). In case of
disconnection from SCADA the PACiS GTW stores events in a queue. For protocols IEC
60870-5-101 or IEC 60870-5-104 the PACiS GTW manages an internal information which
indicates if this buffer ( managed as a circular buffer) is full. Once the communication with
SCADA is recovered this information may be transmitted as first event
In case of SBUS disconnection the PACiS GTW has different behaviors depending on the
value of the register Key
"maintenance_if_dcnx_ethernet" . If this key equals one the
PACiS GTW enters the maintenance mode and the communication with the SCADA is
stopped. If this key equals zero the PACiS GTW transmits to SCADA all server datapoints
with quality field set to Unknown and time stamp field set to the time of the disconnection..
Depending on the TBUS protocol “Unknown” state of data is translated to specific invalid
state.
In case of disconnection of server on SBUS, PACiS GTW send all information of server to
unknown and generates time-stamp. This Change Request allows the user to configure a
time-stamping at reconnexion. This version should not involve in repetition of information
while SCADA switching between Gtw and Gtw backup.
When the communication with the SBUS is recovered the concerned datapoints are
transmitted with their quality field set to Valid. Their time stamp field is either the time of the
reconnection or the time of the acquisition. This way to time stamp datapoints is chosen
during the configuration step.
Detection of disconnection and data invalidity are also transmitted to SCADA when it is an
IED on Legacy BUS under a MiCOM computer that is disconnected. Difference is that
unknown state is then emitted by the IEC61850 server and not by PACiS GTW itself.