Overview of Communications Functions

Section 1-5

5.UDP (User Datagram Protocol)

Performs data communications. Data resends, priority control, flow control, and other measures to ensure communications reliability are not per- formed for UDP communications, so the transmitted data may not arrive at the destination node. To increase reliability, it is necessary to program spe- cial measures into the user applications.

6.TCP (Transmission Control Protocol)

Performs communications after establishing a connection (i.e., a virtual cir- cuit) with the destination node, providing a highly reliable communications service.

7.FINS (Factory Interface Network Service)

A protocol that sends messages between PLCs on any of various OMRON FA networks. To ensure that transmitted messages arrive at the destination node, it is necessary to program special measures such as retry process- ing into the user's applications.

8.FTP (File Transfer Protocol) Transfers data files.

9.SMTP (Simple Mail Transfer Protocol)

A communications protocol for sending e-mail by TCP/IP.

10.POP3 (Post Office Protocol Ver. 3.0)

A communications protocol for receiving e-mail by TCP/IP.

11.SNTP (Simple Network Time Protocol)

A communications protocol for automatic clock adjustment by UDP/IP.

12.DNS (Domain Name System)

A communications protocol for determining IP address names according to UDP/IP and TCP/IP.

1-5 Overview of Communications Functions

1-5-1 FINS Communications Service

Basic Functions

FINS commands can be sent to or received from other PLCs or computers on

 

the same Ethernet network by executing SEND(090), RECV(098), or

 

CMND(490) instructions in the ladder diagram program. This enables various

 

control operations such as the reading and writing of I/O memory between

 

PLCs, mode changes, and file memory operations.

Ethernet

IP UDP or TCP FINS

CS/CJ-series

CPU Unit

IP

UDP or TCP

FINS

Ethernet Unit

Ethernet Unit

Ethernet Unit

User program

SEND(090),

RECV(098), or

CMND(490)

instruction

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Omron CS1W-ETN21 operation manual Overview of Communications Functions, Fins Communications Service, Basic Functions