Communications: electrical – Condition responsive indicating system – With particular system function
Patent
1987-07-07
1989-03-28
Crosland, Donnie L.
Communications: electrical
Condition responsive indicating system
With particular system function
340505, 34082512, G08B 2600, G05B 2302
Patent
active
048168084
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a fire alarm system, and more particularly to a fire alarm system wherein a receiver polls terminal devices having CPU's, such as fire detectors, fire sensors and repeaters and wherein the receiver reads monitoring information from the terminal device called or transmits control information thereto.
BACKGROUND ART
In a fire alarm system, the function thereof needs to be maintained for several hours even under conditions of a power failure, and emergency bells need to be sounded for a fixed period of time in case of the outbreak of a fire during the power failure. Therefore, a receiver has a built-in emergency power source (storage battery).
In a polling type fire alarm system, terminal devices to be polled by the receiver, such as fire detectors, fire sensors and repeaters have built-in CPU's, the consumption currents of which are not negligibly small. Accordingly, when the CPU's are always held in an operating status, the emergency power source of the receiver must have a large capacity.
It can therefore be considered to curtail wasteful power consumption, in cases where a signal transferred from the receiver or any of the other terminal devices is flowing on a signal line, and in cases where, e.g., the operations of reading and sending fire information from the fire detecting portions (detectors or sensors), fire detectors etc. (repeaters), or the operations of delivering control signals to devices to-be-controlled such as local bells and smoke control equipment, by switching the CPU's built in the terminal devices such as fire detectors from a wait status (under which the arithmetic portion of the CPU's are in standby status) into a run status (under which the arithmetic portion of the CPU's are in an operating status).
Even with this measure, however, the CPU's built in the terminal devices are in a run status while the signal is flowing on the signal line, and in the whole system, the large number of built-in CPU's operate simultaneously during the transmission time of the signal. This leads to the problem that the consumption currents during this time are great.
DISCLOSURE OF THE INVENTION
The present invention has been made in view of the background stated above, and has for its object to provide, in a fire alarm system wherein terminal devices such as fire detectors, fire sensors and repeaters have CPU's, respectively, and wherein a receiver polls the terminal devices so as to read monitoring information from a called terminal device or transmits control information thereto, a fire alarm system which can greatly curtail the consumption current of the whole system.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing an embodiment of the present invention.
FIG. 2 is a flow chart showing the major operations of a repeater or a sensor in the embodiment.
FIG. 3 is a flow chart showing the operations of the repeater in the embodiment.
FIG. 4 is a flow chart showing the operations of the fire sensor in the embodiment.
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a block diagram showing an embodiment of the present invention.
The embodiment is equipped with a single receiver R, a plurality of fire sensors S and a plurality of repeaters C. In addition, each repeater C has a plurality of detectors DE and a terminator T connected thereto.
The fire sensors S includes a CPU 10 which controls the entire fire sensor S, a signal receiver circuit 11, an instruction buffer 12 which holds an instruction from the receiver R, an address buffer 13 which holds an address from the receiver R, a light emitting circuit 14, a light receiving circuit 15 which receives light from the light emitting circuit 14, and a holding circuit 16 which holds the output signal of the light receiving circuit. Incidentally, the signal receiving circuit 11 and the buffers 12, 13 constitute transmission signal-receiving means.
Besides, the fire sensor S includes an A/D conversion circuit 17 by which an analog signal from the holding circuit 16 is converted into
REFERENCES:
patent: 4616223 (1986-10-01), Naaijer
patent: 4658243 (1987-04-01), Kimura et al.
patent: 4683531 (1987-07-01), Kelch et al.
Crosland Donnie L.
Nohmi Bosai Kogyo Kabushiki Kaisha
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