S7-400 redundancy mode issue after blackout

We are using S7-400 (redundancy Mode) with S7-300 Distributed IO to control and monitor our HVAC Fan unit.

Recently, after power blackout occurs, the S7-400 wont star!! And remains on stop mode. I figured that the backup batteries for both PLCs (Master and Secondary) are dead. Consequently, we have lost data on the connected HMI and our SCADA system (Modbus data).

Previously, I have made system backup for the project and when I tried to download the project to the PLC, the system faults disappeared, the expansion module in the IO rack faults cleared but the HMI and SCADA still does not recognize our PLC.

the other point, as there are external MC, why the system did not load project from the external memory ?

When I have checked again the PLC hardware configuration, I did not see any setup for the HMI connection in the network configuration layout ?

as a hint, when i downloaded the project again i connected to one PLC and made download for all project, is this correct ? 

Would you please assist us

Hi GazaFso

We are unable to open your attachment.

May be it is correctly not attached.

Can you attach it again properly.

Thanks.