| 摘要 |
PURPOSE:To lead a control subject to the safety side by means of hardware when the abnormality of a microcomputer is produced, by actuating the control subject based on the output of an abnormality detecting circuit that is designated by the microcomputer for each fixed period of time. CONSTITUTION:A CPU 1 outputs an address showing an abnormality detecting circuit 4 for each fixed time and data to a data bus 10 by programs. Here a pulse generating means 6 produces the data pulses which are rectified and integrated by a rectifying/integrating means 7. When the output voltage level of the means 7 exceeds the 1st threshold value V1, a Schmitt trigger means 8 actuates a power relay 9 to attain the energization to a heater 12. If the CPU 1 has the abnormality such as a runaway, etc., no data pulse is produced and the output voltage level falls. When this voltage is less than the 2nd threshold value V2, the operation of the relay 9 is stopped and the energization is stopped to the heater 12.
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