Programmable logic controllers plcs are at the forefront of manufacturing automation many factories use programmable logic controllers to cut production costs and or increase quality plcs and their unique language ladder logic are the workhorses of factory automation higher level languages such as sequential function charts and function blocks ease the programming task for large systems. Programmable logic controllers plcs are at the forefront of manufacturing automation many factories use programmable logic controllers to cut production costs and or increase quality plcs and their unique language ladder logic are the workhorses of factory automation higher level languages such as sequential function charts and function blocks ease the programming task for large systems. Programmable logic controllers plcs are at the forefront of manufacturing automation many factories use programmable logic controllers to cut production costs and or increase quality plcs and their unique language ladder logic are the workhorses of factory automation. Kelvin t erickson missouri university of science and technology abstract in many respects the architecture of the programmable logic controller plc resembles a general purpose computer with specialized input output i o modules. Programmable logic controllers an emphasis on design and application authors kelvin t erickson author publication data rolla mo dogwood valley press publicationeur date 2011 edition eur 2nd ed physical description x 1488 p ill 25 cm 1 cd rom 4 3 4 in subject engineering subject headings programmable controllers