APPX
Appendix 5  TCP/IP Communications, UDP/IP Communications
379
A
Communication flow
This section describes the flow from the establishment of connection to end of communication.
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.
External device
Ethernet-equipped module
Server
Client
Passive open
Active open 
Connection established 
Connection established 
After performing 
Passive open, the server 
will wait for an open request 
from the client.
When the client sends 
an Active open request 
and the server accepts it, 
a connection is established 
between the client and the 
server.
Receive processing
Receive processing
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 processing
Close request
Response
Close request
Close request
Response
ClosedClosed
The packet to stop communications is 
exchanged then the connection is 
disconnected.