Mitsubishi Electric MELSEC iQ-R Series User Manual page 548

Passive open procedure
The following two types of connection methods can be used for Passive open of the CC-Link IE TSN Plus module.
Connection Description
method
Unpassive This connection method executes a passive open processing for the connection to all devices connected to the network without restriction to
the IP address or port number of the communication destination.
Fullpassive When the IP address and port number of the communication destination are specified, this connection method executes a passive open
processing for the connection of the specific external device.
The open/close processing procedure for Passive open follows the setting of "Opening Method" under "Own Node Settings"
in "Basic Settings". ( Page 81 Own Node Settings,  Page 113 Own Node Settings)
■When "Do Not Open by Program" is set
The CC-Link IE TSN Plus module is constantly in the open standby state, so the connection is established when Active open
is initiated by the external device. This eliminates the need for an open/close processing program on the CC-Link IE TSN Plus
module side.
Ex.
Open/close processing for connection No.1
Open status
Open enable status (closed)
(Active open acceptance enabled)
Closed status
'Initial status' (Un\G6291480.0)
'Open completion signal
(connection No.1)'
(Un\G6291456.0)
'Open request signal
(connection No.1)'
(Un\G6291464.0)
 After the module parameters are set, check that the initial processing for the CC-Link IE TSN Plus module has completed normally. ('Initial status'
(Un\G6291480.0): On) When the initial processing completes normally, the connection enters the open enable state, and the module waits for the open
request from the external device.
 The CC-Link IE TSN Plus module executes the open processing when an open request (SYN) is received from the external device. When the open
processing ends normally, 'Open completion signal (connection No.1)' (Un\G6291456.0) turns on and data communication is enabled.
 The CC-Link IE TSN Plus module executes the close processing when the close request (FIN) is received from the external device. When the close
processing completes normally, the open completion signal turns off and data communication is disabled.
 After the internal processing in the CC-Link IE TSN Plus module completes, the connection stands by for the open request again.
*1 The open request (SYN) received between the initial processing normal completion to the open request standby state is handled as an
error, and the CC-Link IE TSN Plus module sends a connection forced close (RST) (to the external device that sent the open request
(SYN)).
When the open/close processing is executed with a dedicated instruction from the CC-Link IE TSN Plus
module, even if "Do Not Open by Program" is set in "Opening Method" under "Own Node Settings" in "Basic
Settings", the connection will not return to the open request standby state after the close processing
completes.
APPX
546
Appendix 8 TCP/IP Communications, UDP/IP Communications
Parameter
communications
completed
Power-on

*1
SYN + ACK

SYN
ACK

FIN + ACK

FIN
ACK