| 摘要 |
PURPOSE:To detect troubles without any complicated hardware by performing a detection program for checking various operations every one cycle of sequence control so that a sequence processing can be performed while no abnormality takes place. CONSTITUTION:A special checking state is set in a state maintaining circuit 1. On the other hand, a detecting program for checking various operation commands entirely is stored in a memory circuit 3. At the first stage of each cycle in the sequence control, an input circuit 2 reads a state from the circuit 1 and sents it to a logic operation circuit 4. A control circuit 5 is operated to checks the operation performed by the commands according to the detecting program. While no abnormality takes place, a sequence control operation program stored in the circuit is executed and the result is inputted to a load 7 through an output circuit 6. |
