Sincerely I have never used the local feature for data files, and I'm not sure if it's really useful in PLC programming, except for a multiple programmers project.
Anyway when I studied programming C language, my teachers always stressed the accent on the importance of a structured style of programming, using subroutines with a local scope of datas, which can be explicitly passed through the other subroutines by the subroutine call declaration.
Why can't this practice be useful with PLCs?
I'm trying to develop for a family of similar projects a library of standard subroutines for state-transition type programs, and I'm wondering if the local scope of variables can be useful for this kind of approach.
Has anyone here worked with local scope data files?