Does Schneider Automation still support the 984 series platform of PLCs? If so what is the programming interface that is used to access the processor and edit code?
Yes, it is still supported.
There are several programming packages offered:
ModSoft (Schneider's DOS-type software, kinda clunky
ProWORX NxT (third party)
FasTrak SoftWorks, Inc. (another third party package)
Yes, they do. Your best bet is to use the Proworx32 originally authored by Taylor Software. It is DOS based, but is very reliable, and one of the best 984 logic editors
Actually most of the new 984 processors are 1131 compliant and you are free to use all the amenities of Concept. You don't need to be constrained to ladder logic.