> You mean to tell me they replaced with PLCs that cost very little
> compared to a PC with PCs.  Bad economic choice to begin with.  Just buy
> one PC, and use it to generate reports, and use the PLCs for real time
> control.  That is what they are designed for.  I haven't seen a real
> time windows yet.

It may have something to do with the big Oracle database and the T1
corporate stuck in a room one day.  Someone must have had this dream
everything should be controlled by One Computer. PLCs are wonderfully
modular and compact compared to large arrays of Opto-22 boards.  There
were open standards for PLCs too, where you could use multiple vendors for
modules in racks.

I could tell you what happened when the proprietary backup software for 
the Oracle server halted.  Let's say when all the lines in the plant 
stopped, I was in the front office on the phone all morning.  And this 
happened a lot.