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Omron CS1W-ETN21 User Manual

Page 140

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Overview of FINS Communications

Section 6-1

• When FINS nodes are connected on the same Ethernet segment:

Use the FINS/UDP method between those nodes.

Note

FINS/UDP offers a slight advantage in performance.

• When FINS nodes are connected over multiple IP network layers:

Use the FINS/TCP method between those nodes.

Note

FINS/TCP offers superior communications quality.

• When the quality of connections is unreliable, as with wireless LAN:

Use the FINS/TCP method between those nodes.

Note

FINS/TCP offers superior communications quality.

6-1-3

FINS Communications Service Specifications for Ethernet

Item

Specifications

Number of nodes

254

Message length

2,012 bytes max.

Number of buffers

192

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-Pro-
grammer's Unit Setup.

Number of connections ---

16

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
• IP address conversion

Items set for each connection

• Server/client specification
• Remote IP address specification

When client: Specify remote Ethernet Unit (server) IP address.

When server: Specify IP addresses of clients permitted to con-
nect.

• Automatic FINS node address allocation:

Specify automatic allocation of client FINS node addresses.

• Keep-alive:

Specify whether remote node keep-alive is to be used.

TCP/IP Setting

• Remote node keep-alive time

Internal table

This 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 Ethernet 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