Areva MiCom P120, Техническое руководство

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Communications P12x/EN CT/A96
COURIER DATABASE
MiCOM P120/P121/P122/P123 Page 3/248
1. K-BUS PROTOCOL AND COURIER LANGUAGE
The serial communications are transmitted on K-Bus, a multi-drop network proposing an
instantaneous interface with IEC 870 - 5 - FT1.2 standards. The language and the
communication protocol used are Courier. This concept permits especially to the generic
programmes of the principal units to access to a high number of different relay types without
need to change permanently the principal unit program for each relay type. The relays forms
a distributed database in which the principal workstation proceeds to a selective call of the
slave relays in order to know all necessary information.
Courier has a concept for the functions with a selective call system which allows not a slave
periphery to communicate directly with the central unit when one shall informs another about
a particular event. The slave workstation has to wait that the principal workstation asks for
the information. With Courier each information is given into a box with a code of the length
and the database type. In knowing the database format the reception periphery can read
them.
1.1 K-BUS
K-Bus is a communication system developed for connecting the slave peripheries in
remoting on the central unit, permitting them to execute all remote monitoring and remote
control functions using the appropriated communication language. K-Bus is not able to
permit a direct communication between the slave peripheries. Only a communication
between the central unit and the slave peripheries can be established. The principal
characteristics of the K-Bus are his profitability, his high security level, his installation facility
and his user friendliness.
1.1.1 K-Bus transmission layer
The communication port is supported on the reception levels and the voltage transmission
RS485 with galvanic isolation assured by a transformer. A selective call protocol is used. No
relay unit is allowed to transmit before having received a validation message without any
error detection. The transmission is synchronous on a pair of isolated waves. The data are
coded FM0 with a clock signal for eliminate all CC-component, allows the signal to cross the
transformers.
With the exception of the central units, each network node is passive. No defective unit from
the system can interfere with the communications established with the other units. The
message format is HDLC. The data transmission speed is 64 kbits/s.
1.1.2 K-Bus connection
The connection on the K-Bus port is realised by screwed terminals of 4 mm of MIDOS
standards or by FASTON-connectors. A cabled pair is sufficient to realise the connection,
knowing that the polarity is not important. It is recommended to use an external screen earth
linked at the end of the principal workstation only. The screen has to be fixed with a M4
screw following the wiring scheme (cf. TG: P12X/EN T). The functioning of the K-BUS
network is guaranteed for 32 units connected on 1000 meters of cables. Thanks to the data
code method, the polarity of the Bus cable connection is not important.
NOTE: The K-Bus network has to finish with a 150 ohms resistance on each
end of the Bus. The principal workstation can be placed anywhere on
the network. This command point has to be unique.
1.1.3 Auxiliary equipment
For communication with the relay it is necessary to have at least one converter case K-
Bus/IEC870-5 of the type KITZ and a computer suitable software, an interconnection cable
RS232 for connecting the KITZ to the computer and a software conform to the specification
of the Courier protocol.