You are kind of comparing apples and oranges..
ie - PLC Vs NI Data acquisition hardware
PLCs were designed with industry in mind, the reason you see designs that appear based in years past is primarily to provide backwards compatibility for the industrial market. Most factories don't want to...
Joepilot - I saw a system like you described once... They had an energy management system that was supposed to disable control power for certain periods. One byproduct of this was that cycling the EMS system could also reset the units in mass. You might look at adding a reset relay to all units...
Direct Logic PLCs use Ladder Logic through a software programming package called Directsoft32. You will also require a programming cable. I am not sure as to the answer to your memory storage over time question...Try this site for basic product support, purchasing, and FAQ...
