Can I upload the application existed on Allen Bradley PLC without having the software application file?

I Have SLC500/05 running in a factory without any documents or application backup. and I need to do some modifications, but first I need to read the existing application from the PLC in a safe way without the source file

 

No problem here, you can just upload the program from the PLC. Having no documentation files does make life interesting, but you should be fine.

 

You can do it, but all the labels comments, etc. are stored with the original program so what you get isn't much fun to work with. RSLogix will ask you if you want to make a new file if it can't find the original.

Regards
cww