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Serial Gateway Overview Section 3-6
3-6-10 Explanation
To treat the serial communications path as a network, the serial port itself is
recognized as a Communications Unit and is allocated a network address.
The CX-Net in the CX-Programmer is used to set the relationship between the
serial port’s unit address and the allocated network address in the local net-
work tables of the routing tables. These settings are then transferred to the
CPU Unit to which the Serial Communications Unit/Board is mounted.
Unit Addresses for Serial
Communications Ports
CS/CJ Series CPU Unit
252 n
Peripheral port
Assigned to network address n
Network
CPU Unit
Local network table in routing tables
Unit number
(See note.)
Set correspondence
Unit address:
253 (decimal)
Commu-
nications
Unit
Serial communications path
Ex-
pressed
as:
Network
address
Unit address:
252 (decimal)
RS-232C port
Note: The unit number is set as a
CPU Bus Unit for Communica-
tions Units, but the unit address
is set for the serial port.
• Peripheral port: 253 (decimal)
• RS-232C port: 252 (decimal)
Serial port
Assigned to network address n
Network
Serial Communications Unit/Board
Local network table in routing tables
Unit number
(See note.)
Set correspondence
Un
Unit address U
(See note.)
Commu-
nications
Unit
Serial communications path
Ex-
pressed
as:
Network
address
Note: The unit number is set as a
CPU Bus Unit for Communica-
tions Units, but the unit address
(80 hex/81 hex + unit number ×
4 hex, as a decimal) is set for
the serial
ort.
PC
Network address n
Serial communications path
Serial Communications Unit/Board
Local network table in routing tables
U
n
Unit number
CX-Net in CX-
Programmer
Local
network
table
Unit address U (80 hex/81 hex
+ unit number × 4 hex)
Network
address
Set the unit address
U as a decimal for
the unit number.
Serial communications port on
CPU Unit
Unit address
Peripheral port FD hex (253 decimal)
RS-232C port FC hex (252 decimal)
CPU Unit
Peripheral port
RS-232C port