Upon shutting down the PLC’s power, the content in the holding register is saved in the SRAM memory, which is sustained by the power of the internal battery. However, if the battery is damaged or cannot be charged, the data in the programs section and the holding register will disappear. If a developer intends to perform permanent backup for the programs section and the holding register of D Register, it would require setting up a Flash ROM permanent backup or recovery. ‧ After opening the ISPSoft software, select Tools->PLC Permanent Backup Setting function to execute back up/recovery. ‧ Select “PLC->Flash” for program/data backup;select “Flash->PLC” for program/data recovery. ‧ Select “PLC Program” to execute program backup/recovery, and then select “D Register” to execute device information backup/recovery.