Mitsubishi Electric MELSEC iQ-R Series - Page 214

212
12 FILE CONTROL
12.4 File Check
■Fixed value
Specify 30H in 4 bytes.
■Drive No.
Specify the access target drive. (Page 198 Drive No.)
■Head file No.
Specify the file No. of the file from which the file information is to be read. (Page 199 File No.)
File No. can be obtained by following command.
Page 217 Search directory/file information (command: 1811)
■Number of requested file
Specify the number of files from which file information is read in the range of 1 to 36. (Page 200 Number of files)
■Directory specification
Depending on the access target, specify any of the following:
• MELSEC iQ-R series (when using subcommand '0040'): Specify the target folder with an absolute path. (Page 200
Directory specification)
• MELSEC-Q/L series (when using subcommand '0000'): Specify '0'.
When checking all files in the specified directory (folder), refer to the following section.
Page 190 Procedure to read information from all files in directory (folder)
Data stored in response data
■Number of file information
The number of file information which has been read is stored. (Page 200 Number of files)
In the following situation, the number of file information will be fewer than the number of requested file.
• When using subcommand '0040', the data of "Number of requested file" cannot be stored at one communication because
the file name length is too long.
• When the number of files exist following the "Head file No." is less than the "Number of requested file".
When no files exist after the specified head file No., the following value is stored.
• MELSEC-Q/L series (when using subcommand '0000'): "Number of file information" = '0'
• MELSEC iQ-R series (when using subcommand '0040'): "Number of file information" = -1 (FFFFH)
■Last file No.
The file No. of the last file from which file information was read is stored. (Page 199 File No.)
For MELSEC-Q/L series (subcommand '0000'), last file No. is not stored.
File No. is also assigned for the system-reserved data that cannot acquire the directory/file information,
therefore, the "Last file No." may differ from the file No. of the last file for the read file information.
Acquire the file No. using the following command.
Page 217 Search directory/file information (command: 1811)
Use "Last file No." in the following process.
Page 190 Procedure to read information from all files in directory (folder)
ASCII code, binary code
ASCII code Binary code
30H 30H 30H 30H
0
30H
0
30H
0
30H
0
30H
00 H 00 H