Question about data recovery

[schnippschnapp]

2. Redundancy PLC 400 extend load memory is RAM. so for the PLC all the load memory is RAM, When I warm restart the CPU one by one .the data for the PLC will not be lost right??
But for non redundancy PLC, when I warm restart the CPU the data (like: FB FC DB ) will be disappeared, if I want to make recovery the system I need to download the data from PC to CPU right ? for redundancy PLC I do not need to download the data,right ?

[schnippschnapp]

other two questions are splitted to following threads

When will *.ldf and*.mdf files be updated?.

When shall we need to delete the data in the MMC card and for what kind of reason ?.
Thanks gent

If the power supply is equipped with an operational backup battery, or the CPU is supplied

with an external backup voltage at the "EXT. BATT." input, the RAM card contents are

retained when power is switched off, provided the RAM card remains inserted in the CPU

If the power supply is interrupted, the warm restart function is only available in backup

The preset master/reserve assignment is retained when both CPUs power up

The master/reserve assignment changes when:

1. The reserve CPU starts up before the master CPU (interval of at least 3 s)

The master CPU checks and updates the memory content of the reserve CPU before the

fault-tolerant system assumes redundant system mode. This is implemented in two

successive phases: link-up and update.