Mitsubishi Electric MELSEC-L Series - Communication Process

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CHAPTER 7 COMMUNICATION PROCEDURE
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7.2 TCP/IP Communications 7.2.2 Communication process
7.2.2 Communication process
This section describes the process from establishing a connection to terminating communications.
Connected device
E71
Server
Client
Passive open
Active open
Connection established
Connection established
After the server performs
Passive open, it will wait
for an open request from
the client.
When the client sends
Active open request and
the server accepts it,
the connection is
established between
the client and the server.
Receive process
Receive process
Open request
Response
Data sending
Data sending
Response
The client requests data
sending and sends data.
The client receives the response
to the data.
The client receives data and sends
back the response to the data.
Data sending
Data sending
Response
Close process
Close request
Response
Close request
Close request
Response
ClosedClosed
The packet to stop communications is
exchanged then the connection is
disconnected.