Mitsubishi Electric MELSEC iQ-R Series - Internal Buffer

20 DATA LOGGING FUNCTION
20.8 Steps Until the Collected Data Is Saved
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Internal buffer
The internal buffer is a system area used to temporarily store collected data.
The collected data is temporarily stored in the internal buffer and stored in the specified data storage destination memory at
the time of a file save operation.
Internal buffer capacity setting
Set the capacity of the area (internal buffer) used by the system to temporarily store the results of data logging. The capacity
can be set individually for each data logging setting number (1 to 10).
[CPU Parameter]  [Memory/Device Setting]  [Internal Buffer Capacity Setting]
For trigger logging, increasing the internal buffer capacity allows an increase in the number of collected data before trigger
and also helps to prevent processing overflow. If the free space in the internal buffer is still insufficient after increasing the
internal buffer capacity, use the following workarounds:
• Increase the data collection interval or timing.
• Reduce the number of data records to be collected.
• Lower the frequency of file switching.
Window
Displayed items
*1 Leaving this field blank allows the setting to be unused (0K bytes).
Amount of internal buffer consumed
This value can be calculated by multiplying "Number of data points" by 2 bytes. Note, however, that additional space is
consumed by columns configured for output, as indicated below:
• Date/time column: 10 bytes
• Data collection interval column: 8 bytes
• Execution step No. column: 10 bytes
• Execution program No. column: 2 bytes
• Index column: 4 bytes
Ex.
When data logging is configured to collect as much data as one setting x 128 records and output all of the columns (i.e.,
maximum allowable configuration):
128  2 + (10 + 8 + 10 + 2 + 4) = 290 bytes
Item Description Setting range Default
Total Capacity Shows the total of the internal buffer
capacity set in the data logging function.
64 to 3072K bytes 1536K bytes
Data
Logging
Function
Total
Capacity
Shows the total of the internal buffer
capacity used for the data logging function.
 1280K bytes
Setting
No.1 to 10
The internal buffer capacity used for each
Setting No. of the data logging settings
• Each setting range: 32 to 3040K bytes (in increments of 1K bytes)
*1
• Total setting range: 32 to 3040K bytes
128K bytes