Precautions - Mitsubishi L02CPU User Manual

10.5

Precautions

This section provides precautions on using this function.
(1) Precautions on the file transfer function (FTP client)
(a) FTP server connection
When a connection is set up with the FTP server, KeepAlive is used to verify the connection.
An alive check message is sent five seconds after reception of the last message from the FTP server to check
if the FTP server returns a response or not. If no response is received, alive check messages are sent at 5-
second intervals.
If no response is received for 45 seconds, the FTP server is assumed as not alive and the connection is
disconnected.
If the FTP server is not compatible with the TCP KeepAlive function (responding to KeepAlive ACK messages),
the connection may be disconnected.
(b) Communication error during file acquisition
If the FTP client file get instruction (SP.FTPGET instruction) is used to get a large file, the load of transfer
processing will be increased and a communication error may result.
When transferring a large file, make proper settings of the FTP server, such as maximizing the connection time
(timeout time), to prevent a communication error from occurring.
(c) Execution of file transfer function instruction during execution of another function
If one of the following functions is active when the file transfer function instruction is executed, the instruction
will be completed with an error.
• Project data batch save/load function
• iQ Sensor Solution function (data backup/restoration)
(d) Execution of another function during execution of file transfer function instruction
If one of the following functions is executed during execution of the file transfer function, an error will result.
• CPU module change function with memory card
• Project data batch save/load function
• iQ Sensor Solution function (data backup/restoration)
(2) Precautions on operations from peripherals
(a) File access
If the file being accessed by this function is accessed by other peripherals, the error processing corresponding
to the relevant peripheral may occur.
Do not allow peripherals to access the relevant file while SM721 (file accessing flag) is on.
If the error corresponding to the peripheral does not occur during execution of the FTP client file send
instruction (SP.FTPPUT), the file data being transferred to the FTP server is possibly damaged.
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