Areva MiCOM P341 - IEC 60870-5 CS 103 Communication

Operation Guide P341/EN O/B11
Introduction CHAPTER 1
MiCOM P341 Page 19/22
Note: *May vary according to relay type/model
‘Communications’ column from the column heading to the first cell down which
indicates the communication protocol:
Protocol
Modbus
The next cell down controls the Modbus address of the relay:
Modbus address
23
Up to 32 relays can be connected to one Modbus spur, and therefore it is necessary
for each relay to have a unique address so that messages from the master control
station are accepted by one relay only. Modbus uses an integer number between 1
and 247 for the relay address. It is important that no two relays have the same
Modbus address. The Modbus address is then used by the master station to
communicate with the relay.
The next cell down controls the inactivity timer:
Inactivity timer
10.00 mins
The inactivity timer controls how long the relay will wait without receiving any
messages on the rear port before it reverts to its default state, including revoking any
password access that was enabled. For the rear port this can be set between 1 and
30 minutes.
The next cell down the column controls the baud rate to be used:
Baud rate
9600 bits/s
Modbus communication is asynchronous. Three baud rates are supported by the
relay, ‘9600 bits/s’, ‘19200 bits/s’ and ‘38400 bits/s’. It is important that whatever
baud rate is selected on the relay is the same as that set on the Modbus master
station.
The next cell down controls the parity format used in the data frames:
Parity
None
The parity can be set to be one of ‘None’, ‘Odd’ or ‘Even’. It is important that
whatever parity format is selected on the relay is the same as that set on the Modbus
master station.
3.8.3 IEC 60870-5 CS 103 communication
The IEC specification IEC 60870-5-103: Telecontrol Equipment and Systems, Part 5:
Transmission Protocols Section 103 defines the use of standards
IEC 60870-5-1 to IEC 60870-5-5 to perform communication with protection
equipment. The standard configuration for the IEC 60870-5-103 protocol is to use a