Computer-based controller whose functionality is determined by a so-called user program. The user program can be generated relatively easy due to standardized technical terminology [
Instruction list,
FBL,
LAD,
SFC,
ST].
Because of their serial mode of operation their reaction times are more slowly compared to
WPC.
Nowadays PLC controls all levels of an automation hierarchy in form of device ranges with graded components coordinated according to their power.
