File Control Execution Procedure For The Qnacpu - Mitsubishi Electric MELSEC IQ-R series Reference Manual

File control execution procedure for the QnACPU

The following shows the procedures for executing file control on QnACPU.
Procedure when reading contents of file
1.
Check for file existence.
Check with any of the following commands.
• Page 308 Read file information table without header statement (command: 0201)
• Page 311 Read file information table with header statement (command: 0202)
• Page 314 Read file presence (Search file) (command: 0203)
2.
Prohibit access from other devices. (Prohibit file content modification.)
• Page 321 Register and deregister file locks (command: 0808)
3.
Read all content of the file.
• Page 318 Read file (command: 0206)
4.
Allow access from other devices. (Allow file content modification.)
• Page 321 Register and deregister file locks (command: 0808)
Store the following file information of the file (for storage) read to an external device.
• File No.
• File name and file attribute
• File size
Procedure when overwriting data to existing file (changing file information)
1.
Check for file existence.
Check with any of the following commands.
• Page 308 Read file information table without header statement (command: 0201)
• Page 311 Read file information table with header statement (command: 0202)
• Page 314 Read file presence (Search file) (command: 0203)
2.
Prohibit access from other devices. (Prohibit modification of file.)
• Page 321 Register and deregister file locks (command: 0808)
3.
Before changing the file size, change the QnACPU status to STOP.
4.
Write data when overwriting or copying data, or changing file size.
• Page 325 Write to file (command: 1203)
5.
Modify the file creation date and time.
• Page 329 Modify file information (command: 1204)
6.
Allow access from other devices. (Allow file content modification).
• Page 321 Register and deregister file locks (command: 0808)
*1 The file size can be changed using the file information modification function (Page 329 Modify file information (command: 1204))
only when the file size is made smaller. When the file size must be made larger, write data in the same procedure as create a new file.
(Page 307 Procedure for creating a new file and write data to it (creating a file by copying))
15 QnACPU DEDICATED COMMANDS
306
15.3 File Control
*1