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FINS Communications Section 9-5
9-5 FINS Communications
9-5-1 FINS Communications Service Specifications
Note Refer to the following diagram for the relation between message length and date length.
Item Specification
Number of nodes 254
Message Length 1016 bytes max.
Date Length 1004 bytes max. (See note)
Number of buffer 14 (1016 bytes×6+240 bytes×8)
Protocol name FINS/UDP method FINS/TCP method
Protocol used UDP/IP TCP/IP
The selection of UDP/IP or TCP/IP is made by means of the
FINS/TCP Tab in the CX-Programmer’s Unit Setup.
Number of connections --- 2
Port number 9600 (default)
Can be changed.
9600 (default)
Can be changed.
Protection No Yes (Specification of client IP
addresses when unit is used as a server)
Other Items set for each UDP port
• Broadcast
• Address conversion method
Items set for each connection
• Server specification
• Remote IP address spec.
Server: specify IP addresses of clients permitted to
connect.
• Automatic FINS node address allocation
Specify automatic allocation of client FINS node
addresses
Internal table This is a table of correspondences for remote FINS node addresses, remote IP
addresses, TCP/UDP, and remote port numbers. It is created automatically when power is
turned ON to the PLC or when the unit is restarted, and it is automatically changed when
a connection is established by means of the FINS/TCP method or when a FINS command
received.
The following functions are enabled by using this table.
• IP address conversion using the FINS/UDP method
• Automatic FINS node address conversion after a connection is established using the
FINS/TCP method
• Automatic client FINS node address allocation using the FINS/TCP method
• Simultaneous connection of multiple FINS applications
10 bytes 2 bytes
Date length
Command code
1004 bytes max.
FINS header
Message length: 1016 bytes max.