Omron CS1W-ETN21 operation manual Exchanging Data between Omron PLCs using Ethernet, Reference

Ethernet Unit Function Guide Section 1-1

Connecting through multiple segments, such as over the Internet:

Use FINS/TCP.

CX-Programmer

FINS

IP router

Firewall

Internet

(Server room)

Ethernet

	Connecting from a computer with a dynamic private IP address:
Intranet	Use FINS/TCP or FINS/UDP.

(Office floor)

CX-Programmer

FINS

Ethernet

Router

Router

(Production line)	CX-Programmer		Connecting within the same segment:
			Use FINS/UDP.
		FINS
Ethernet

Ethernet Unit	Ethernet Unit
	PLC	Wireless	CX-Programmer
			Using media with unreliable
			connections, such as wireless
			LAN: Use FINS/TCP.
			FINS

Reference SECTION 6 FINS Communications

Exchanging Data between OMRON PLCs using Ethernet

Connecting within the Same Segment

Connecting through Multiple Segments

Use the UDP/IP version of the FINS communications service (i.e., FINS/ UDP), and construct applications using the SEND(090), RECV(098), and CMND(490) instructions in the ladder program. FINS/UDP is supported by many OMRON products, and is compatible with earlier Ethernet Units (CS1W- ETN01/ETN11 and CJ1W-ETN11). The protocol processing for FINS/UDP is simpler than for FINS/TCP, giving FINS/UDP certain advantages in terms of performance. Another feature of FINS/UDP is that it can be used for broad- casting.

On the other hand, with FINS/UDP it is necessary to provide measures, such as retries, for handling communications errors.

Use the TCP/IP version of the FINS communications service (i.e., FINS/TCP), and construct applications using the SEND(090), RECV(098), and CMND(490) instructions in the ladder program. FINS/TCP is the initial func- tion supported by this Ethernet Unit (CS1W-ETN21 and CJ1W-ETN21). It pro- vides automatic recovery at the TCP/IP layer from communications errors (such as packet loss) that occur during multilevel routing.

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