Method and apparatus for recovering normality in moving sequence of

Abstract

In order to execute a series of moving sequences by synchronous and exclusive control of unit operations taught or programed in advance, there are provided a first storing of the relationship of the sequence of execution of each unit operation to other unit operations to be controlled synchronously or exclusively; a second storing of information relating to the operational status of each unit operation; and a third storing of operating instructions for executing each unit operation. When machine tools have stopped due to the occurrence of an abnormality while a series of unit operations are being executed by the operating instructions stored in the third storing means, a unit operation for restarting on the basis of the relationship of the executing sequence stored during the first storing is appointed, and information concerning the operational status stored during the second storing is corrected. Furthermore, at the time when a junction operation in which there exist two or more sequences leading to a unit operation has been executed, a fourth storing is effected during the normal state of the operation steps relating to that execution. Then the content of the information stored during said second storing is corrected to a state permitting restarting from an appointed unit operation by referring to information stored during the fourth storing.