What to do when original program is not available?

I'm sure this situation has happened many times before and the question already asked, but I can't find any answers.

We have a system on our site, and to cut a long story short, we aren't on best terms with the company that supplied it.

We do not have the original PLC program for this system, and the company won't supply it.

I have made a back up of the PLC software, and made backups of the HMI software.

Currently I'm not interested in making any changes to the software.

My only concern is the event of PLC failure. If the PLC were to fail, and I use the backup file I have taken from the PLC, the HMI screens are not shown in the program therefor are not networked.

Is there any way to network the HMI screens using a program backed up from the PLC?

Thanks,

Tom.

which PLC?

if you restore the backup the HMI is not affected from that and should work as before

It's a 1511-1 PN. 

So when I do a backup from the PLC should I be seeing all the network connections?

Currently all I see is the PLC itself and nothing else.

Due to not having the original program, I had to create a new project, add an unidentifed S7 1500 PLC, plug into the PLC, detect the hardware and upload the software.

try it with a new empty project and then accessible nodes

select the PLC and in menu online -> load device as new station

then also HW Config and networks should be uploaded.

Looks much better, I can now see 2 I/O Devices and 2 Drives. However when connecting to the drives I have:

And I'm still unable to see the HMI's.