Back up battrey for 400H system

Saga

Dear Experts,


For the Hsystem there is requirement that Customer dont want to replace battery so that program should be there permenantly even if there is power loss.

What is the solution for this?

Even if we are using Flash memeory card then what will be the effect on the plan or is it same???

Thanks in Advance

The S7-400H power supply modules support the use of two backup batteries.This allows
you to implement the following:

-Back up the user program stored in RAM

-Retain bit memories, timers,counters,system data and data in variable data blocks.

-Back up the internal clock.