S5-CX945 (Substitute for irreparable S5-PLC Controls)

Dear Friends,
Refering to subject line, I would like to ask you that if any one has ever used S5-CX945 for upgradation from S5 series outdated Siemens PLC. I am working for a Palm Oil Refinery which is around 10 yrs old & is having S5-115U PLC. There are no spare cards & many of the inputs are burnt & most of the spares I/O's are used. I am thinking of suggesting upgrade to my management. With the cost sensitive market today I want to spend least possible amount. In nut shell I am thinking of changing PLC only & not the old WIZCON SCADAD system. The more I have read about S5-CX, I think it will be compatible with old WIZCON system also.( A fact I am yet to establish!!!! ) But all I am asking you gyus the feasability of using this as a improvement from S5 series & what are the maximum I/O exapansion possible with it. Is it only a processor which will go with old S5 I/O's or it comes with its own I/O's.
Regards,
Neeraj

I have zero experience with it. But I know this:
You cannot realistically reuse the S5 i/o with the CX945.
This CPU integrates into Beckoffs hardware manager. So you can combine with Beckhoff i/o and also add Profibus networks for example.
I dont think the CX945 is a magic bullet for old S5 plants.

The best advice I can give is to plan for a complete change of everything S5 (!). As for the SCADA, maybe it can be upgraded to a current version at a reasonable cost.

With todays PLCs you can get a lot of bang for your buck.
Costwise I am confident that a new S7 PLC (or other new PLC) is cheaper than reparing or working around an obsolete S5 PLC.
The biggest hurdle is the actual changeover.

Dear Jesper,
Thanks for quick reply. You are correct. What I fear is changeover. The original plant was supplied by Desmet Belgium, which has some special subroutines may be password protected. Now why I got interested in S5-CX is I don't have to change on program a bit. It will take my old S5 program as it is. I have tried in the past with upgradation of Step 5 program into Step 7 in one of my past job. With Simens Step 5-> Step 7 utility also there are some subroutines which cannot be changed, you have to do it manully & then it becomes quite cumbersom job & needs really an expert ( in other words more involvement of cost ).