S7 Upload advice

Hi
I have an S7 program written by a previous employee. I went to the site and found miscompares of blocks etc.

I obviously wanted to back the program before i did any work.

What is the preferred method of uploading? On other PLC types I simply upload and 'blow over' the existing program where as I had to create a new program and upload on S7, losing all symbols and rung comments. I realise I can copy the symbol file over but lose the rung comments.

Cheers

Quickest way to get a back-up, make a copy of the existing file and upload to that.

Then you have your back-up.

Next compare your original to the PLC and see what the differences are.

Code blocks (FC, FB, etc) can usually be uploaded OK providing there are no rungs added/deleted. Although saying that if the code is in STL, then code descriptions can be moved within a rung.

DB's can be uploaded without losing the symbolic names, provided the DB length has not changed.

The best way is usually the longest way though, look at the changes found via compare and write them in.

Thanks for that Peter.

So, in a scenario....

Integrator 1 does the job and has fully documented program.

Integrator 2 turns up and does a whole lot of changes to Integrator 1's fully documented program. He then goes bust or gets kicked off site without providing any of his own documentation.

Can Integrator 1 upload the program and retain the original comments etc or is it neccesary to manually compare on a block by block basis and maybe manually recreate the new blocks to retain the documentation.

Cheers

I found the best way is to compare then copy the updates, that way your comments will be in sync with the segments.
One thing that could be a problem is any changes to the datablocks.

Thanks. I dont do too much S7 so I am always a bit wary when I get dropped in at the last minute.



Cheers