Abstract: A transmission processing unit is disposed in a terminal sensing device for a disaster prevention monitoring system. The transmission processing transmits a detection data to a central unit of the system, only when the detection data is equal to or higher than a predetermined level threshold and a difference between the detection data and a detection data of a preceding transmission is equal to or larger than a predetermined level difference threshold .DELTA.TH. Alternatively, the transmission processing unit transmits the detection data to the central unit of the system, only when the detection data is equal to or higher than the predetermined level threshold and a time period which is elapsed after the transmission of the preceding detection data is equal to or longer than a predetermined time period threshold.

Abstract: Disclosed is a monitoring apparatus for disaster prevention which allows the setting of relay unit data to be revised with ease by effectively utilizing the information transmitting function between the receiver and the relay units. The monitoring apparatus for disaster prevention comprises relay units equipped with a storage device.

Abstract: This invention is directed to an output correction system for an analog sensor which outputs an analog signal corresponding to a quantity of state. The output correction system for the analog sensor comprises a control section which receives an output from the analog sensor obtained under condition where the quantity of state is zero and an output from the analog sensor obtained under pseudo-condition equivalent to a certain quantity of state; a first arithmetic section for calculating a gradient on the basis of the output under the zero condition and the output under the pseudo-condition; a storage section for storing output characteristics defined by said gradient; and a second arithmetic section for calculating a quantity of state corresponding to the output from the analog sensor on the basis of the output characteristics defined by the gradient.

Abstract: A fire alarm system having a plurality of fire detectors connected in parallel with each other to a pair of power/signal lines leading to a central signal station and adapted to respond to the signal station with a detection signal in the mode of current and controlling the signalling between the fire detectors and the signal station. The detection of a fire is accomplished by computing a difference between a steady-state current flowing through the signal lines and a detection current which are detected in an analog amounts. Each of the fire detectors is called by a simple calling clock pulse whose transmitting timing is controlled by a microcomputer of the central signal station to transmit a detection data. The generation timing of the calling clock pulses is freely selectable to effect a desired control of the fire detectors.

Abstract: In a fire detection system having at least one fire sensor, a receiver including a power source connected to the fire sensor for supplying a power source voltage to the fire sensor and a receiving relay for receiving a fire detection signal from the fire sensor, and at least one power/signal line for coupling the fire sensor to the receiver, the receiver comprises a timer for producing a clock signal over the time of day and command means for providing predetermined detection sensitivity change commands of the fire sensor which are programmed according to the time of day in response to the clock signal from the timer, and the fire sensor comprises sensitivity change control means for changing the detection sensitivity of the fire sensor in response to the detection sensitivity change command from the command means. The fire detection sensitivity of the fire sensor is varied in accordance with predictive fire damage conditions predetermined in view of the activities of people during the time of day.