| 摘要 |
PURPOSE:To contrive to establish the set temperature at the temperature control within a vinyl plastic hothouse by a constitution wherein, when the firing realizes after the predetermined number of ignition trials, the normal running is restored and the combustion is continued. CONSTITUTION:In stead that the instant safety stop action is taken when firing fails to realize, it is so constituted that the safety stop action is taken when firing fails even after the execution of predetermined number of ignition trials. Concretely, a multiple ignition circuit 25 consists of comparators CMP1-CMP3 are one-shot multivibrator circuits OS1-OS3 connected to the respective output terminals of CMP1-CMP3. The respective comparators CMP1-CMP3 compare the charging voltage VIN of a capacitor C1 with the pre-set reference voltages V1-V3. When VIN exceeds the respective voltage V1-V3 as charging proceeds, transistors Q1-Q3 are turned ON pulsewise through the one-shot multivibrator circuits OS1-OS3. The pulse is waveform-shaped at an ignition reset circuit 22 and then inputted to the 2 terminal of IC20 in order to reset IC20. |
