| 摘要 |
PURPOSE:To increase safety of an combustion control device, by providing a gate circuit adapted to block an emission of signal indicating a heat demand when an abnormal signal indicating an occurance of abnormality in the device is detected, thereby ensuring to stop a sequence circuit at an abnormal status. CONSTITUTION:If an electric power is switched ON when a heat demand signal TH is high, every parts is made is reset, and a signal PON is rendered high after a timed duration preset by a time constant of resistor 9 and capacitor 10, while a differentiation circuit 2-1 starts to output a signal THON when a sending of clock signal phi is started via an AND gate 3-5. A transistor Tr13-2 is turned ON when an AND gate 3-8 has its output lowered, thereby lowering a signal EM indicating an occurance of emergency. On the other hand, if a signal PON is slow to energize after the power is switched ON, an output of buffer 5, i.e. a signal PON is ensured to be low, and memories 12-1 and 12-2 are reset via a latch 16, thereby enabling the transistor 13-2 to stop a sequence circuit upon the former being turned FF. |
