Mitsubishi Electric Q01UCPU User Manual page 314

(1) Setting method
To use the operation history function, select the "Save operation history of CPU module" checkbox in the PLC
RAS tab of the PLC parameter. (
For a system where data is frequently written to devices and files, set a large capacity to save many histories. When setting
a large capacity, specifying the SD memory card is highly recommended as the save destination memory.
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Page 439, Appendix 1.2.4)