JPS57139813A - Controller - Google Patents

Abstract

PURPOSE:To raise the reliability for detecting a fault, by automatically detecting the fault of a computer at all times, raising the reliability of a computer control by taking proper steps quickly, and especially providing a simple fault deciding circuit separately from the computer system. CONSTITUTION:An absolute value generator 11 generates an absolute value of an output of a computer 7, it is compared with a prescribed value, and an output of a comparator 12 becomes ''1'' or ''0''. A reset pulse generator 14 commands to detect a fault of the computer 7, an integrator 13 resets its output value to ''0'' at every period tau by its pulse, and otherwise, an output of the integrator 13 shows the time when an output of the computer 7 exceeds a threshold level. In case when the time when the absolute value of the output of the computer 7 is larger than the threshold level of the comparator 12 is long in the period tau, a comparator with holding 16 regards it a fault, outputs ''1'', and outputs ''0'' if said time is short. In short, a fault deciding circuit for comparing the absolute value of the set value of the output and detecting the continuous time is improved.