I have encountered memory backup battery failure/fully drained in MITSUBISHI A2SH PLC.So RUN LED started flashing on PLC. Thus no field parameters values were being shown on HMI. I connected PC with PLC through serial RS232 cable using GX DEVELOPER 8 , the connection test was successful. Then I tried to download my project saved on PC to PLC, then I was amazed as It asked for a keyword. However when the backup battery was working , I downloaded the same project but it did not ask for any keyword. Can anyone explain this. Now the real problem is that the program was developed by somebody long ago , to whom I don't have any contact right now and I m helpless as I don't know the keyword and can not download the program and thus my machine is at halt. I tried to clear the user memory from online menu , but it says the function not supported. I m stuck and frustrated . Anybody 's help is greatly appraised in anticipation. Of course I m not asking for hacking a keyword. Just to know how can I make my system functional. Thanks everybody.