Internal Buffer - Mitsubishi Electric MELSEC iQ-R Series User Manual

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
Item Description
Total Capacity Shows the total of the internal buffer
capacity set in the data logging function.
Data Total Shows the total of the internal buffer
Logging Capacity capacity used for the data logging function.
Function
Setting The internal buffer capacity used for each
No.1 to 10 Setting No. of the data logging settings
*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
Setting range
64 to 3072K bytes

• Each setting range: 32 to 3040K bytes (in increments of 1K bytes)
• Total setting range: 32 to 3040K bytes
20.8 Steps Until the Collected Data Is Saved
Default
1536K bytes
1280K bytes
*1
128K bytes
20 DATA LOGGING FUNCTION
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