I am a little confused by the title "DRPINT IN MEMORY CARD....".
From what you described, it sounds like you want to make an SRAM backup of the machine memory to a USB device? This is normally done in the boot screen using a memory card. The boot screen does not support USB.
You can make an SRAM backup to a USB device but you will need to boot up in IPL mode.
Hold " - " (minus) and " . " (decimal) in while booting up. It takes some time for the screen to appear so be patient.
Select BATCH DATA BACKUP / RESTORE (12)
Select BATCH DATA BACKUP CNC TO USB MEMORY (11)
You can also restore the SRAM from IPL