START SUPERVISORY SYSTEM OF INFORMATION PROCESSING UNIT

PURPOSE:To attain automatic program restart when a specified data is not set by supervising whether or not the specified data is set by a check point provided at required locations of the program after program start. CONSTITUTION:An error takes place in a block B and a scan-in instruction B is not executed, then a register 20B is not inverted. Since a signal 21B keeps a high level, a time supervisory signal 105B is set and a free rank lock signal 104 is set succeedingly, then the condition of an AND circuit 40B is established and a restart signal 42 is outputted. Then a retrial signal 43 is fed to a processing unit for restart. Further, the signal is fed to a time supervisory clock generating circuit to reset a counter for restart. Thus, error detection circuits 100A-100N detect that a data 11 is not set within a specified time in a register 22 of a start supervisory device 5 from the processing unit by power-on operation, the retrial reset signal 43 is outputted to relieve automatically an error such as disabled run or runaway.