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MELSEC-F
OVERVIEW
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1.3 Software Configuration
The Ethernet modules support the TCP/IP and UDP/IP protocols.
(1) TCP (Transmission Control Protocol)
This protocol guarantees data credibility and reliability in communication between
a personal computer/work station and PLC that are connected via network, and
provides the following functions:
• Creates a logical connection by establishing a connection (logical line) as if a
dedicated line was created between external devices.
• A maximum of 8 connections can be established and communicated with at the
same time in the Ethernet module.
• Data reliability is maintained by the sequence control using the sequence
numbers, the data retransmission function and the check sum.
• The communication data flow can be controlled by operations using Windows.
User program
Buffer memory
Communication
using fixed buffers
Communication
using the MC protocol
Communication
by e-mails
TCP/UDP
IP
ICMP
ARP
Ethernet
(100BASE-TX,10BASE-T)
TCP
IP
UDP
Ethernet
(100BASE-TX, 10BASE-T)
ICMP
ARP
System call
PLC
Ethernet
module
Personal computer/work-station(example)
PLC
Main Unit
SMTP
POP3
DNS
OSI reference model corres-
ponding to the PLC configuration
(Layers)
Application layer
Presentation layer
Session layer
7
6
5
Transport layer
4
Network layer
3
Data link layer
2
Physical layer
1
Socket
FROM/TO instruction