some plc related resource ,pls enjoy them!
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[001]. plc wiki,
http://en.wikipedia.org/wiki/Programmable_logic_controller
[002]. introduction to PLC controllers:
http://en.wikipedia.org/wiki/Programmable_logic_controller
[003]. PLC Primer:
http://www.plcs.net/contents.shtml
[004]. linux plc:
http://plc.sourceforge.net/
[005]. puffin project:
http://puffinplc.control.com/
[006]. plcs site:
http://www.plcs.net/
(to be continue ... )
