Operation of S5-110A (6ES5900-7AD11)

Hi, i am after some assistance. I currently have a S5-110A PLC (6ES5900-7AD11) and I am looking to convert to a TIA Portal PLC. I have a printed copy of the program but the programmer has used certain flags a number of times throughout the program  and he has called them "Mehrfachmerker" which I have translated to "Multiple Marker". He seems to have used these flags a multitude of times just before the flag is used in the code for an output or to set a flag.

I have only worked with PLC's since OB1 has been used.

Am I right to assume the S5-110 PLC works top to bottom rather than as now where OB1 controls the cycle? 

Does anyone have any links where I might find manuals for this PLC type?

I do not know if it can help you.

I have 2 old manuals to the S5-110A, unfortunately only in german.

However, the PDF files are too large to attach to the post.
So I uploaded it to a filehoster.

http://www103.zippyshare.com/v/GVLsn8DN/file.html

 Hello,

Goody

 I am looking to convert to a TIA Portal PLC.

 Perhaps the following  FAQ might help:

Migration Guide: SIMATIC S5 to SIMATIC S7-1500