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Modbus TCP
11.4.5
The Modbus TCP can support the communication over the Ethernet. The Ethernet provides
the Modbus TCP (see Figure 11.4-1). TCP and IP layers detect errors over the Ethernet, so the
error check one is omitted here. The Modbus TCP will be set when the setting
[MODBUS_SELECT] = TCP.
Communication
10:48
1/7
LAN
USBCOM
RS485
SLAVE PROTOCOL
IEC61850
IEC103
MODBUS
Note: Each IED (Slave) can be identified by an IP address. Thus, the user does not have
to set the setting [MODBUS ADDR] (see sec. 11.4.4(ii)-1) when the TCP is set.
Network structure
(i)
Figure 11.4-9 shows the IEDs(Slave) connect with substation computer(s)(Master) through
Ethernet ring LAN. IEDs can communicate with up to 6 substation computers, and serval
architectures and speeds can be defined by the LAN communication modules†.
Remote monitoring
Message frame
TCP slave response
IED (Slaves)
Device1
(192.168.1.11)
Figure 11.4-9 Ethernet ring LAN by Modbus TCP/IP
†Note: See Chapter
can set an IP address with setting [IPADDRESS1] (see Figure 11.2-1).
MODBUS
10:48
>
MODBUS_BLK
>
Off
>
MODBUS ADDR
>
>
MODBUS_SELECT
>
Serial (➔TCP)
>
Figure 11.4-8 Switch to the Modbus TCP
Communication
Network
Router/
Modem
Ethernet LAN
Device2
(192.168.1.12)
Technical description: Communication modules
- 924 -
1/3
+
+
2
Press
+
set [MOSBUS_SELECT]=TCP
Substation Computer(s) (Master)
TCP master query
Device3
(192.168.1.13)
6F2T0207 (0.01)
Press
ENTER
key
, , ,
to
Message frame
Device X
(192.168.1.XX)
(→p. 645). The use
GRE200 (5,6)
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