I'm looking for security and backup software for PLC ladder logic. I've looked at Rockwell Software and MDT Software, are there any others. We are using AB 5040Es and 5080Es, plus some Siemens 500 series processors.

 

I can only vouch for the MDT software. We have used it in several plants and it is a pretty good system, although they still have bugs they are working out. Rockwell has security server, but I don't if it would be compatible with your Siemens processors. We use MDT to back up Allen Bradley PLCs, SLCs, PanelViews, Devicenet files, and GEFanuc robots.
I would also be interested to hear of any software packages other than Mass and Security Server (I think that is the Rockwell name)

 

What about a more generic solution?
E.G. Microsoft Visual Source Safe. Provides logins, file history etc.

 

One of the best ones I have used is the FxManager from GE-Fanuc/Cimplicity-Total Control/Taylor software.
Has Plug_ins for most of the major players and solid product. here's the link to the main page.
http://www.gefanuc.com/totalcontrol/products/fxmanager_ams/auto_mgt_home.html