1 DATA COMMUNICATION USING MC PROTOCOL
1.2 Data Communication
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1
File access method
To access to a file, which the password setting is configured, from external devices using the MC protocol, specifying the
command for file password is required.
1. Specify the password with a request message.
2. Perform the password authentication by using the specified password.
For command requiring the password authentication, specify "0040" with the setting value of "subcommand" in the request
message.
For more details on the commands, refer to the following manual.
MELSEC Communication Protocol Reference Manual
1.2 Data Communication
MC protocol uses the following communication frames for data communication.
Transmit/receive data from the target device in the data format corresponding to the MC protocol.
For details on the communication frames format, refer to the following manual.
MELSEC Communication Protocol Reference Manual
Formats and codes
There are five formats for the data communication frames:
Set the format in the Communication protocol setting of an Engineering tool.
Communication using binary code shortens the communication time since the amount of communication data
is about a half of the one in data communications using ASCII code.
Function Command (subcommand)
Deleting file 1822 (0040)
Copying file 1824 (0040)
Changing file attribute 1825 (0040)
Opening file 1827 (0040)
Setting
value
format Code of communication data Remarks Reference
1 Format 1 ASCII code MELSEC Communication
Protocol Reference Manual
2 Format 2 ASCII code A format that a block number is added
3 Format 3 ASCII code A format enclosed with STX and ETX
4 Format 4 ASCII code A format that CR and LF are added at the end
5 Format 5 Binary code This can be used only for 4C frame.
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