Communication Flow - Mitsubishi Electric MELSEC iQ-RJ71EN71 User Manual

Communication flow

This section describes the flow from the establishment of connection to end of communication.
Ethernet-equipped module
After performing
Passive open, the server
will wait for an open request
from the client.
Connection established
Receive processing
Wait at least 500ms or more before executing the open processing again after the close request is sent from
the external device to the Ethernet-equipped module.
Server
Passive open
Open request
Response
Data sending
Response
Data sending
Data sending
Response
Close request
Response
Close request
Close request
Response
Closed
Client
External device
When the client sends
an Active open request
and the server accepts it,
Active open
a connection is established
between the client and the
server.
Connection established
The client requests data
Data sending
sending and sends data.
The client receives the response
to the data.
The client receives data and sends
back the response to the data.
Receive processing
Close processing
The packet to stop communications is
exchanged then the connection is
disconnected.
Closed
Appendix 5 TCP/IP Communications, UDP/IP Communications
A
APPX
379