PURPOSE: To simplify the constitution of a system and to reduce its price by providing the system with a delay means for detecting an external input signal belonging to a previously set inherent level range and driving an operation testing means only when the detection signal is inputted for a prescribed time.
CONSTITUTION: When the degree of a sensed fire cause reaches a fire level, a fire alarming means outputs a fire signal. An operation testing circuit 10 turns the fire alarming means to a fire detecting state. A judging means detects an external test signal belonging to the previously set inherent level range and outputs a detection signal. At the time of inputting the detection signal from the judging means for a prescribed time, a delay circuit 9 drives the circuit 10. Namely the circuit 9 is reset in each input of a detection signal from an AND circuit 8 and starts time counting to count up the continuous input time of the detection signal. After counting up the prescribed time, time limitation is executed, and simultaneously with the time limitation, a signal is outputted from the circuit 9 to the circuit.
JPH1145383 | MONITOR AND CONTROL SYSTEM |
WO/2000/021046 | SIGNALING FIRE DETECTOR |