Omron CS1W-ETN21 Overview of Fins Communications, Communications On an Ethernet Network

Overview of FINS Communications Section 6-1

6-1 Overview of FINS Communications

6-1-1 Communications On an Ethernet Network

Data is sent and received as UDP/IP packets or TCP/IP packets on an Ether- net network.

PLC

Ethernet Unit

or host computer

Packet (FINS command)

Ethernet

Packet (FINS response)

Ethernet Unit

PLC

In the FINS communications service, both an IP address for IP (the Internet layer) and a FINS node address for FINS (the application layer) are used for the remote device. Also, 9600 is used as the default setting for the local UDP or TCP port number (i.e., the transport layer) for identifying the application layer, i.e., the FINS communications service. (Another number can be set for the FINS/UDP port from the Setup Tab in the Unit Setup.)

For details on pairing FINS node addresses with IP addresses and UDP/TCP port numbers, refer to 5-2 IP Addresses in FINS Communications.

Application Layer

Transport Layer

Internet Layer

Physical Layer

FINS
	Node Number
UDP	TCP
UDP Port No.	TCP Port No.
IP
	IP Address
Ethernet
	Ethernet Address

The FINS communications service is a communications method based on UDP/IP, and it is supported by most OMRON Ethernet-related products. (In this manual it is called the FINS/UDP method.) In addition to supporting the FINS/UDP method, the CS1W-ETN21 and CJ1W-ETN21 support FINS com- munications using TCP/IP. (In this manual, this is called the FINS/TCP method.)

6-1-2 Using the FINS/UDP and FINS/TCP Methods

It is recommended that FINS/UDP and FINS/TCP be used as follows:

•When remote devices do not support the FINS/TCP method:

Use the FINS/UDP method for FINS communications with those devices.

114