Connection With The Ftp Server; Communication Error When Retrieving Transfer Files; Execution Of The Sd Memory Card Forced Disable Function; Deleting Unnecessary Files - Mitsubishi Electric MELSEC iQ-RJ71EN71 User Manual

Precautions

Connection with the FTP server

If a response to an alive check request is not returned from the FTP server, the CPU module (FTP client) determines that the
FTP server is not alive and disconnects the connection.
The connection may also be disconnected if the FTP server does not support the TCP KeepAlive function (response to a
KeepAlive ACK message).

Communication error when retrieving transfer files

If a large capacity file is retrieved by execution of the SP.FTPGET instruction, a communication error may occur due to an
increase of the transfer processing load. When transferring a large capacity file, extend a connection time (timeout period) in
parameters for the FTP server so that no communication error occurs.

Execution of the SD memory card forced disable function

If the SD memory card forced disable function is executed, use of the SD memory card is disabled in the middle of the transfer
processing, causing an immediate stop of the processing. Check that the transfer processing has been completed, and
execute the function.
Execution of a file transfer function instruction during execution of another function
A file transfer function instruction cannot be executed during execution of the following functions. Check that the following
function is not being executed, and then execute the instruction.
• CPU module data backup/restoration function
• iQ Sensor Solution data backup/restoration function
File operation from the external device during file transfer
Do not manipulate the files from an external device, such as an engineering tool, while transferring the files.
If the file is manipulated from another device while transferring the files, the external device may issue an error. If the
processing has been halted due to an error, re-execute the processing after the file transfer operation.
Communication processing
If another communication function (MELSOFT connection or SLMP) is simultaneously executed with UDP/IP during file
transfer with FTP, an error such as timeout may occur. Either communicate after the file is transferred, or communicate with
TCP/IP.

Deleting unnecessary files

If a cable is disconnected, system is powered off, or the CPU module is reset during the file transfer, delete unnecessary files
(such as a temporary file and undefined files) in the FTP server. Then, transfer files again.
When the process CPU (redundant mode) is used
■System switching during the file transfer
• When the system switching occurs during the file transfer by an engineering tool, the system switching instructions, or the
system switching request from the network module, the system will be switched after completed the processing.
• When the system switching occurs because of power-off, reset, hardware failure, or stop error during the file transfer, the
connections between the FTP server and old control system cannot be disconnected properly. In this case,
communications may not be performed with the new control system until disconnection of the old control system is
recognized due to FTP server timeout. To reconnect with the FTP server, keep an attempt to execute until the connection
with the FTP server becomes open. In addition, delete unnecessary files on the FTP server when the files are generated.
The files are not remain in the FTP server since the FTP connection are not connected even when the system switching is
executed other than during the file transfer.
1 FUNCTIONS
1.10 File Transfer Function (FTP Client)
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