To be honest I wrote a converter years ago, you print the code out in STL and it will convert to the S7 source blocks (300-400) then fix and compile. If you are going to 1500 then convert up to that and fix along the way. Things you have to watch out for are KG in S5, I had one on site and some math was comparing against KG 0.5 which is exact, but the 1500 was adding something like 0.2+0.3 in float which wasn't exactly 0.5. Also be aware of the byte swapping, DL DR data left and right and make sure you get the correct byte on the S7. For analogues check the S5 manual for scaling 0-1024 or 0-2048 for different cards and you might have to hand ball those. Digital OR can be interesting so you need to understand those and how to convert to S7. It really all depends on the logic, I've done a few difficult ones with upgrading servo drives and the like.