scheider electric MiCOM P746, Техническое руководство

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P746/EN SC/G31 SCADA Communications
(SC) 13-
8
MiCOM P746
SC
Having made the physical connection to the relay, the relay’s communication settings must
be configured. To do this use the keypad and LCD user interface. In the relay menu firstly
check that the ‘Comms. settings’ cell in the ‘Configuration’ column is set to ‘Visible’, then
move to the ‘Communications’ column. Only two settings apply to the rear port using Courier,
the relay’s address and the inactivity timer. Synchronous communication is used at a fixed
baud rate of 64kbits/s.
Move down the ‘Communications’ column from the column heading to the first cell down
which indicates the communication protocol:
Protocol
Courier
The next cell down the column controls the address of the relay:
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.
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 MiCOM S1 V2 or Studio do not require this
action for the setting changes to take effect.
1.2.3 MODBUS communication
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.