Abstract: A transfer machine comprising a conveyor for conveying workpieces to stations and numerically controlled machine tools disposed at their respective stations. These machine tools are controlled by sequence controllers, which are connected with their respective numerical controllers. All the programs for machining operations are stored in each numerical controller. When some station is in trouble, the normal machine tool disposed at a station adjacent to the station in trouble is caused to execute the program originally assigned to the station in trouble, as well as the program assigned to the normal station itself.

Abstract: A general purpose sequence controller wherein a schematic electric circuit diagram comprising a ladder network of circuit lines disposed between two vertical bus lines is changeable and simulated by a special purpose control program. A logic operation circuit comprises first and second circuit means for examining an external input signal in accordance with examine commands of logical AND and OR functions, respectively, first and second memory means for temporarily memorizing the examined results of the first and second circuit means, respectively, third memory means for temporarily memorizing the application of the examine command of the logical OR function, and identifying circuit means for identifying the examined results of the logic operations in accordance with the contents of the first, second and third memory means.