Chace Donald E, Melvin Jr James A, Ricketts Jr Alan W, Steinberger Edward P, Symmes David T: Analyzer for sequencer controller. Digital Equipment Corporation, October 24, 1972: US3701113 (45 worldwide citation)

A monitor for a programmed sequence of operations. A sequence controller responds to successive instructions. Some instructions correspond to elements of governing functions and test the status of independent variables to activate controllable devices, which correspond to dependent variables, when f ...