PLC

from The Free On-line Dictionary of Computing (8 July 2008)

Programmable Logic Controller
PLC

   <hardware> (PLC) A device used to automate monitoring and
   control of industrial plant.  Can be used stand-alone or in
   conjunction with a {SCADA} or other system.

   (1997-02-11)

from V.E.R.A. -- Virtual Entity of Relevant Acronyms (June 2006)

PLC
       PowerLine Communications [adapter]

from V.E.R.A. -- Virtual Entity of Relevant Acronyms (June 2006)

PLC
       Programmable Logic Controller (IC)