x/EN SC/Na7
-8 MiCOM P74
Remote address
1
Since up to 32 relays can be connected to one K-bus spur, as indicated in Figure 2, 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. Courier uses an integer number between 0 and 254
for the relay address, which is set with this cell. It is important that no two relays have the
same Courier address. The Courier address is then used by the master station to
communicate with the relay. Default value of remote address is 255 and must be changed to
6 for the P741 or a value in the range of 7 to 34 for the P742 and P743.
The next cell down controls the inactivity timer:
Inactivity timer
10.00 min.
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.
Note that protection and disturbance recorder settings that are modified using an on-line
editor such as PAS&T must be confirmed with a write to the ‘Save changes’ cell of the
‘Configuration’ column. Off-line editors such as S1 do not require this action for the setting
changes to take effect.
1.2.3 MODBUS communication (not available)
MODBUS is a master/slave communication protocol, which can be used for network control.
In a similar fashion to Courier, the system works by the master device initiating all actions
and the slave devices, (the relays), responding to the master by supplying the requested
data or by taking the requested action. MODBUS communication is achieved via a twisted
pair EIA(RS)485 connection to the rear port and can be used over a distance of 1000m with
up to 32 slave devices.
This protocol is not available.
1.2.4 IEC60870-5 CS 103 communication
The IEC specification IEC60870-5-103: Telecontrol Equipment and Systems, Part 5:
Transmission Protocols Section 103 defines the use of standards
IEC60870-5-1 to IEC60870-5-5 to perform communication with protection equipment. The
standard configuration for the IEC60870-5-103 protocol is to use a twisted pair EIA(RS)485
connection over distances up to 1000m. The relay operates as a slave in the system,
responding to commands from a master station.
To use the IEC60870-5-103 communication, the relays have to be connected to a KITZ274.
A KITZ274 converter can manage up to 8 P74x relays with consecutive addresses.
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