I'm not sure I understand the question either. If I remember correctly, A-B PLC's can be configured with any of several communications protocols (DH2, Modbus+, even ethernet, etc.) Are you just needing PLC software that runs on a Linux operating system? I'm presuming you have a Linux unit you want to utilize, what communication protocols do you have available for your Linux unit? Someone hot on A-B PLC's would know about available software, or maybe an A-B rep.
I know A-B has a website, you might also try AutomationDirect (do a yahoo search for the web address). Sorry if this is simplistic and old information to you.