Replacing power supply of S-400 which is in RUN mode, without any stop

[Razmjoo]

Hi experts!!

Please suppose we want to replace the power supply of PLC S-400 which is in RUN mode, without any stop in process. So what we can do?

Plug S-400 CPU by Ext-BATT(5-15VDC) cable?! Then turn off the power supply module and then remove it from the rack?

So I think, at least external fault LED turn on because of the difference between configured hardware and present hardware, yea?!

So after replace a new power supply on rack and turn it on, we can unplug S400 CPU from Ext-BATT(5-15VDC) cable and then turning off the external fault LED by pressing FMR button?!

[CoMod]

S7-400 processor and input/output modules is powered through the backplane.
Ext-BATT(5-15VDC) input is powered RAM only
http://s7detali.narod.ru/PS_Sitop/PS405.html

[Razmjoo]

What a ridiculous mistake I was. thanks alot.

But what can I do for Replacing power supply of S-400 which is in RUN mode, without any stop?! Only redundancy?1

[CoMod]

Only if use 2 CPU S7-400H in redundancy mode.