Mitsubishi Electric MELSEC iQ-R Series User Manual page 187

• Active open
The following figure shows the flow of data exchange using Active open.
Start
Open processing
Was data transfer
completed?
NO
Send data by the SOCSND instruction, or receive
data by the SOCRCV or SOCRCVS instruction.
• Passive open
The following figure shows the flow of data exchange using Passive open.
Start
Is data sent or received?
YES
Send data by the SOCSND instruction, or receive
data by the SOCRCV or SOCRCVS instruction.
Precautions for TCP/IP communications
■Conditions for closing
In addition to when close is requested from the external device, the TCP/IP communications processing will be closed in the
following cases if 'Open completion signal' (Un\G6291456) turns off.
• When alive check function times out
• When forced close is received from external device
■TCP/IP connection elements
The TCP/IP connection is managed with the following four elements. Only one connection containing the same four elements
can be created at one time. To use multiple TCP/IP connections simultaneously, ensure that one of the four elements is
different.
• IP addresses of CC-Link IE TSN Plus modules
• Port numbers of CC-Link IE TSN Plus modules
• IP address of the external device side
• Port number of the external device side
Note that when "Unpassive Connection Module" or "Fullpassive Connection Module" is selected, the port number of the CC-
Link IE TSN Plus module side has to be different. In addition, one of the other three element also has to be different.
■Reconnecting with same connection
After closing the connection during TCP/IP communications, wait at least 500ms before reconnecting to a connection with the
same external device (IP address), own station port number, and external device port number.
If a wait interval cannot be provided before reconnecting, changing the own station port number on the Active open side and
connecting is recommended.
Specify the port number of the external device waiting for
TCP connection and open a connection by Active open.
YES (Sending data completed, or the connection is
disconnected by the external device.)
Close processing
End
Waiting for TCP connection in Passive open state.
NO
9 FUNCTIONS
185
9.4 Ethernet Connection
9