What do you mean by the configuration? Serial configuration or some data that you saved to the PLC?
The PLC's DMs are volatile so their values are lost when power is off. There are two ways to tackle this issue if non-volatility is important:
1) Install an MX-RTC which will provide battery backup to the RAM data when power off (selectable by DIP switch #1)
2) Store the data that need to be saved to the EEPROM using the SAVE_EEP command whenever the data is updated. Then use a 1st.Scan pulse to trigger a custom function which runs the LOAD_EEP command to load the saved data back into the DMs.