Mitsubishi Electric MELSEC iQ-R Series User Manual page 190

Communications using UDP/IP
Communication with UDP/IP uses a simple protocol without order control or re-send control.
Check the following items before performing socket communications using UDP/IP.
• IP addresses and port numbers on external device side
• IP addresses and port numbers of CC-Link IE TSN Plus modules
Precautions for UDP/IP communications
• Loss of data, data arrival order interchange, and others could be occur. Consider using TCP/IP if there are problems.
• Even if the communication line between the CPU module and external device is not connected because of a connected
cable disconnection and others, the data send processing may end normally. Thus, providing a communication procedure
and sending/receiving data is recommended.
• 'Open completion signal' (Un\G6291456) and 'Open request signal' (Un\G6291464) for the connection set to UDP/IP is
always on.
• Do not execute the CONCLOSE instruction in the program. If the CONCLOSE instruction is executed, the open completion
signal and open request signal for the corresponding connection will turn off. The close processing will be executed and
send/receive will be disabled. To re-open a closed connection, execute the CONOPEN instruction.
• Even if 'Open completion signal' (Un\G6291456) is turned on, data sending may fail. If data sending fails, send the data
again.
Precautions
This section describes the precautions for exchanging data with socket communications.
■Port number
For the port number of the own station used in the system, refer to the following to use a free port number.
Page 550 Port Number
■Relaying between ports
The Ethernet device connected to the port 1 side of the CC-Link IE TSN Plus module and the Ethernet device connected to
the port 2 side cannot relay between the ports, and socket communications cannot be performed.
■Reading received data
If 'Socket reception status signal' (Un\G6291472) is on, read the received data. The communication could be affected if large
amounts of data are not read out for a while.
■Accessing a file during communication
The CPU module prioritizes the file access processing over the Ethernet communication processing. Thus, if the file is
accessed with FTP, the engineering tool, and so on, during socket communications, the socket communications processing
could be delayed.
To access a file while monitoring the response time with the external device with socket communications, add the time
required for accessing the file to the monitoring time.
■Module FB and dedicated instruction
• When performing the open processing using the module FB or dedicated instruction, start sending and receiving data after
the module FB or dedicated instruction is completed.
• Multiple module FBs or dedicated instructions to one connection cannot be simultaneously executed. When multiple
module FBs or dedicated instructions are simultaneously executed, no operation is performed for the module FB or
dedicated instruction executed later. Execute again after the module FB or dedicated instruction in execution is completed.
9 FUNCTIONS
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9.4 Ethernet Connection