| 摘要 |
PROBLEM TO BE SOLVED: To securely generate an alarm only when a device really stops by permitting a monostable multivibrator to execute the resetting of a multistage flip flop constituting a frequency divider. SOLUTION: A monostable multivibrator 241, an oscillator 242 generating a flop signal, multistage flip flop circuits(FF) 2431-243N and an alarm signal generation flip flop 244 are provided. The output of the vibrator 241 is inputted to the flip flops 2431-243N and the reset terminal of the flip flop 244. The oscillator(OSC) 242 and the flops 2431-243N constitute the frequency divider. Time from the stop of a system monitoring device to the output of an alarm signal can be set for long time and stably not by the monostable multivibrator which is difficult to set precise and long time but by freely setting the oscillation frequency (clock period) of the oscillator 242 and/or the number N of the stages of the flops 2431 to 243N. |
