Communications: electrical – Condition responsive indicating system – With particular system function
Patent
1993-10-04
1996-02-20
Coles, Sr., Edward L.
Communications: electrical
Condition responsive indicating system
With particular system function
340518, 340588, 34082506, G08B 2600
Patent
active
054932718
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a fire alarm system having a fire receiver, terminal devices such as transmitters and fire detectors connected to the fire receiver, and devices to be controlled such as fire doors and local alarm sounding devices, and more particularly to the transmission of a fire signal, a control signal and the like between the terminal devices and between the fire receiver and the terminal devices.
2. Background Art
Recently, a polling-type fire alarm system has been employed in a building having a relatively large size. In a fire alarm system of the foregoing type, fire information (whether or not a fire signal is present and a physical quantity signal of a fire phenomenon) and control information (an operating command and a restoring command to the device to be controlled, and state signal of the device) are transmitted and received between a fire receiver and terminal devices disposed at various portions in the building, namely, supervisory terminals such as fire detectors and gas leakage detectors, transmitters to which devices to be controlled such as fire doors, smoke dampers and smoke barrier are connected, and analog fire detectors and the like. The fire receiver has an internal ROM (Read Only Memory) which previously stores the addresses of the terminal devices, contents to be displayed at the time of a fire, and linkage information about the devices to be controlled and the like. In accordance with the stored information, the transmitters and the analog fire detectors and the like are polled to collect fire information and information about the devices to be controlled. If information indicating the occurrence of fire has been determined from the fire information, the discriminated contents are displayed and the relative devices to be controlled are linkage-controlled.
Since the conventional polling-type fire alarm system has been constituted while using the fire receiver as the main device as described above, information cannot directly mutually be transmitted and received between the terminal devices such as the transmitters and the analog fire detectors. If information is transmitted and received between two transmitters for example, the fire receiver must be interposed. The reason for this is that the timing for the terminal device to transmit the signal is determined by the fire receiver without exception.
Therefore, the load for the fire receiver to bear is too heavy, and accordingly, a problem arises in that a failure of the fire receiver deteriorates the overall function of the system.
Further, in the conventional polling-type fire alarm system, the signal transmission between the fire receiver and the terminal devices has been performed while employing a predetermined signal length, that is, a fixed length. If a signal having a length except for the predetermined length is received, a discrimination is made that a transmission error has occurred. The reason for this is that the signal transmission rate between the fire receiver and the terminal devices must be raised to detect a fire and to give an alarm as soon as possible.
In a case of a plant consisting of a multiplicity of buildings or a large-scale building such as a skyscraper, a very large number of supervisory devices, such as fire detectors, and devices to be controlled are connected to the fire receiver through transmitters, or a multiplicity of analog detectors are connected to the fire receiver. If the building is enlarged or the layout is changed, the numbers of the supervisory terminals, the devices to be controlled, the transmitters and the analog fire detectors are increased or the contents to be displayed on the fire receiver are changed.
In the conventional arrangement in which a ROM in the fire receiver previously stores various information items (the addresses of the terminals, data about the contents to be displayed and data about linkage-control and the like) about the terminal devices, the enlargement of the building or the layout change of the bu
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Kobayashi Takashi
Tsumuji Akio
Coles Sr. Edward L.
Lee Thomas D.
Nohmi Bosai Ltd.
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