S7 400 plc password

Somebody know how to delete a password from a PLC in order to reprogram it?

You Just Have To Whipe Out The Memmory Out. Hope You Had A Back Up Of The Ladder.

Thanks for your response. Im already delete all PLC program, we have removed the battery and also the memory card and live it for a while, of course after do this all PLC program gone, after this we have tried to reload the program but anyway ask for a password.

There is another way to kill all PLC memory in order to also kill the password??

"diagnostics/settings" from the PLC tab , select "clear/reset"

if you have no password, you have to buy a new CPU to substitute the CPU protected by password.

I wish sombody can give a novel method to clean the password or unlock the password for S-400.