Drive - Mitsubishi Electric MELSEC iQ-R Series User Manual

Drive

Drive structure
A generic term for the file storage memory and the SD memory card slot of the Motion module is called "Drive". The following
shows available drives of the Motion module.
: Available, : Not available
Item User drive
Usage • Project data
• General data
Drive identifier /rom
*1
Memory capacity 16M bytes
[RD78G]
64M bytes
[RD78GH]
File system Equivalent to
FAT16(VFAT)
Format necessity before Not necessary
the first usage
*1 Total capacity including file management area. The available capacity is smaller.
*2 Power off is protected. (The file system is not damaged even if the power is off during writing.)
*3 Formatting is completed prior to shipping.
*4 Formatting is completed prior to power on/reset. (The file is deleted at power on/reset.)
*5 To format an SD memory card, format it with the CPU module. If formatted with such as the Windows formatting function, an SD memory
card may not be able to be used by inserting it into the Motion module.
The drive that can be used may be restricted depending on functions. Also, the function may be restricted
depending on the drive to be used. Refer to each function for details.
Drive status
The drive status can be checked by STORAGE_INFORMATION type variable (System.Md.Storage_<drive>) which
corresponding to each drive. (The <drive> indicates drive identifier: rom, sys, ram, lch, sdc.)
Variable/Structure name
STORAGE_INFORMATION.Capacity
STORAGE_INFORMATION.FreeSpace
STORAGE_INFORMATION.Mount
Memory life
■Life of flash ROM
Since a user drive and system drive use a flash ROM, it has writable times (life). An indication of write times can be monitored
by System.Md.HwStatus_RomWriteCycle and data can be written until it reaches to 100,000 times. If the value exceeds
100,000 times, it is registered in the event history.
If the write count index value exceeds 100,000 times, the following symptoms may occur. Replace the Motion module.
• Decrease of writing speed to file
• Unable to write data to file
The write count index value may not match the write count by user operation. For example, the write count index value may
not increase even if data is written to a file.
System drive
• Module software
• Addon
/sys
8M bytes
[RD78G]
24M bytes
[RD78GH]
Equivalent to
*2 *2
FAT16(VFAT)
*3 *3
Not necessary
Description
Stores the drive capacity in a unit of 1k bytes.
Stores the drive vacancy capacity in a unit of 1k bytes.
Indicates the drive mounted status. Furthermore, it indicates file access is available when it is set to TRUE.
RAM drive Latch drive
Work data • Absolute position
data
• Synchronous
restoration data
/ram /lch
16M bytes [RD78G] 240k bytes
32M bytes [RD78G]
[RD78GH] 480k bytes
[RD78GH]
FAT16(VFAT) FAT12(VFAT)
*4
Not necessary Not necessary
SD memory card
• Project data
• General data
/sdc
maximum 32G bytes
*2
SD memory card:
FAT16(VFAT)
SDHC memory card:
FAT32(VFAT)
*3 *5
Not necessary
19 FILE CONTROL
497
19.1 Memory and File
19