s7-1200 error and deleting retained data

[rQx]

Hi,
I have a s7-1200 at home that went into "CPU error: Serious firmware exception". After a power cycle it was OK again, but all retained data was lost. Is there a way to prevent this from happening? Not the CPU error, I guess it can happen. But the retained data? Can a memory card in the CPU prevent this? I thought the retained data was stored in the CPU. Maybe the issue was that it thought the memory card was changed? (I have no memory card in it)

After the power restored it said:

Security information: Memory card exchanged during power off - current card type: No memory card
Security information: PLC project changed Load memory control

 

[BryanG]

I would make sure the firmware is up to date, people seem to have reported this in the past. A few years back I had a couple of PLCs loose their program entirely. I upgraded firmware and wondered about power supply issues, so I added Varistors to my 24V d.c. circuits on top of existing back emf protecting diodes.

 

[rQx]

I would make sure the firmware is up to date, people seem to have reported this in the past. A few years back I had a couple of PLCs loose their program entirely. I upgraded firmware and wondered about power supply issues, so I added Varistors to my 24V d.c. circuits on top of existing back emf protecting diodes.

Thanks I'll do that
/Tim