IntroductionofProgrammablecontrollersFromasimpleheritage,theseremarkablesystemshaveevolvedtonotonlyreplaceelectromechanicaldevices,buttosolveanever-increasingarrayofcontrolproblemsinbothprocessandnonprocessindustries.Byallindications,thesemicroprocessorpoweredgiantswillcontinuetobreaknew