System Memory (Backup Ram); Precautions - Mitsubishi Electric MELSEC iQ-R Series User Manual

System memory (backup RAM)

System memory (backup RAM) is a file system (latch drive) which stores the backup data used for the control in an add-on
library. System memory (backup RAM) size is as shown below.
Model
System memory (backupRAM) size
System memory (backup RAM) usage setting
The amount of system memory (backup RAM) available in each add-on library is set by
System.PrConst.Addon_AddonLibraryName.BackupRamSizeMax. Memory usage between each function can be flexibly
adjusted according to the application with this parameter.
System memory (backup RAM) usage setting method
The maximum amount of system memory (backup RAM) used in the add-on can be set by the engineering tool.
• The maximum usage of system memory (backup RAM) can be set in K bytes.
• The set maximum usage is applied at system start.
The current/maximum amount of system memory (backup RAM) used in the add-on can be monitored by
System.Md.Addon_AddonLibraryName.BackupRamUsage/System.Md.Addon_AddonLibraryName.BackupRamMaxUsage
respectively. The value is stored in K bytes.
The current/maximum total amount of system memory (backup RAM) used in all add-ons can be monitored by
System.Md.MemoryUsage.BackupRamUsage/System.Md.MemoryUsage.BackupRamMaxUsage respectively. The value is
stored in K bytes.
Ex.
Examples of adjustable memory:
• Number of ABS axes
• Number of event history storage
• Number of synchronous restoration function axes

Precautions

If the maximum usage of system memory (backup RAM) is changed, the backup data stored in the system memory (backup
RAM) will be cleared.
Precautions
• The system memory usage can increase/decrease depending on the usage of add-on libraries. Allow a margin for the
maximum memory to use.
• When more system memory capacity is required during RUN, an error or a warning is output for each add-on library. If
memory cannot be secured in the function that affects the control, the whole module will be stopped as the WDT error.
RD78G
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RD78GH
3 BASIC FUNCTIONS
3.3 System Memory Settings
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