Precautions - Mitsubishi L02CPU User Manual

13.4

Precautions

The following describes precautions for the IP address change function.
(1) Power-off and reset operations
Do not power off or reset the CPU module while writing to or clearing the IP address storage area (flash ROM).
Values may not be reflected to the IP address storage area (flash ROM). Check that SM1293 (IP address storage
area write complete) and SM1296 (IP address storage area clear complete) turn on before powering off or
resetting the CPU module.
(2) IP address of parameters
For IP address of the built-in Ethernet port, values in the IP address storage area (flash ROM) take priority over
values of parameters. To use the IP address specified by parameters, clear the value in the IP address storage
area (flash ROM).
(3) Duplicated IP addresses
When changing an IP address, check that the changed IP address is not the same as that of other devices. If IP
addresses are duplicated, communication may be performed with a wrong device.
The duplicated status can be checked by either of the following methods.
• By using the Find CPU function
• By disconnecting an external device from the network and performing a PING test to the IP address of the
disconnected external device. (The IP address is duplicated if a response message is returned.)
(4) Functions that cannot be performed during write processing and clear
processing
The following functions cannot be executed during the write or clear processing to the IP address storage area.
Do not execute the functions before the processing is completed. Doing so may cause an error.
If operation of writing to or clearing the IP address storage area (flash ROM) is executed during the execution of
the following functions, the write or clear operation is processed as an error.
• Online program change
• Copy program memory data into ROM
• Write to PLC (flash ROM)
(5) Execution timing of write processing and clear processing
• Since the status of SM1292 (IP address storage area write request) and SM1295 (IP address storage area
clear request) are checked in the END processing, processing of writing to or clearing the IP address
storage area (flash ROM) cannot be executed if a contact is turned off and on, or turning on and off in one
scan.
• If SM1292 (IP address storage area write request) is turned off and on again while writing to the IP address
storage area (flash ROM), the write processing executed earlier is completed properly and the processing
executed later is ignored. (The same occurs for the clear operation.)
• If SM1295 (IP address storage area clear request) is turned off and on while writing to the IP address
storage area (flash ROM), the clear operation is processed as an error. (The same occurs when the write
operation is executed during the clear processing execution.)
• If SM1292 (IP address storage area write request) and SM1295 (IP address storage area clear request) are
turned off and on in one scan, the write operation is prior to be executed, and the clear operation is
processed as an error.
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