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9 Communication
9.2 Modbus
152
SICAM MMU 7KG9663, Device Manual
E50417-H1040-C514-A3, Edition 01.2016
9.2.4
Communication with the Subdevice SICAM I/O Unit 7XV5673
Principle of Data Exchange of the SICAM I/O Unit 7XV5673 with a Substation Controller via SICAM MMU with IEC
60870-5-104 Protocol
To add 6 binary inputs and 6 binary outputs, you can connect the SICAM MMU to a SICAM I/O Unit 7XV5673
via the Ethernet interface. You can establish this connection as follows:
•
Direct connection using a Y-cable when using the Ethernet switch implemented in the SICAM I/O Unit
•
Connection via an external Ethernet switch
The following figure illustrates the interconnection of the SICAM MMU with a substation controller and the SI-
CAM I/O Unit 7XV5673. Modbus TCP is used as transmission protocol. Communication to both the Modbus
TCP master and the SICAM I/O Unit 7XV5673 with the Modbus UDP protocol is accomplished via the same
physical Ethernet interface.
Fig. 9-3
SICAM MMU Connected to a Substation Controller and the SICAM I/O Unit 7XV5673 –
Modbus TCP
Binary
Outputs
Indications
from Remote
Binary
Inputs
Indications
from Remote*
Modbus Server/
Modbus Mapping
Modbus Client
from I/O Unit:
Binary Inputs
Request telegram
(Modbus function 23)
Response telegram
(Modbus function 23)
SICAM I/O Unit 7XV5673
SICAM MMU 7KG9663
Modbus TCP Server/
Modbus TCP Mapping
to I/O Unit:
Binary Outputs
Substation Controller
Modbus TCP Client
Modbus TCP
request
Modbus TCP
response
* Alternatively , a SICAM MMU
internal indication (e.g. Limit
Violation or Group indication ) can
be transmitted to the IO Unit .
Binary Input x
from I/O Unit
SICAM-MMU_7KG9663_US.book Page 152 Monday, December 7, 2015 12:22 PM