Mitsubishi Electric MELSEC iQ-R Series User Manual page 362

*5 If a string terminator (0) is used halfway in the data, the data after it are not output.
The size of the data line (maximum) is calculated as shown below. For a CSV file, replace the number of tabs with the number
of commas and divide the total size by 2.
When logging 256 points worth of word [unsigned]/bit string [16-bit] decimal format (0 digit) data
(Date column: YYYY/MM/DD hh:mm:ss.s, Index column: output)
Data line size
= 42 [date column] + 20 [index column] + 12  256 [data column] + 514 [number of tabs] + 4 [CR+LF]
= 3652 [bytes]
APPX
360
Appendix 9 Data Logging File Format