Communications: electrical – Condition responsive indicating system – With particular coupling link
Reexamination Certificate
2001-10-23
2003-04-08
Pope, Daryl (Department: 2632)
Communications: electrical
Condition responsive indicating system
With particular coupling link
C340S514000, C340S517000, C340S506000, C340S538000, C340S533000, C340S535000
Reexamination Certificate
active
06545602
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fire alarm system.
2. Description of the Related Art
Conventionally, in a fire alarm system consisting of fire receivers connected to each other by a LAN, fire detection information of fire receivers is shared between each of the fire receivers connected by the LAN.
In addition, in the conventional fire alarm system, as a plurality of terminal apparatuses connected to a fire receiver, controlled apparatuses such as area sound apparatuses and smoke preventing and exhausting apparatuses which operate in correspondence with an issue of an alarm of a fire sensor that detect a fire are connected to the same fire receiver. The linkage therebetween is made by the unit of a receiver.
In addition, a fire alarm system is configured such that a plurality of fire receivers are connected by a LAN (Local Area Network), respectively, and share data by exchanging data signals (hereinafter referred to simply as signals). In this case, there are two ways in which a signal is transmitted. One is the case in which a fire receiver transmits a signal to another fire receiver. The other is the case in which a fire receiver transmits a signal to all the other fire receivers connected to the LAN, which is a so-called global transmission. The global transmission will be specifically described in this specification. When a fire receiver carries out the global transmission, the other fire receivers transmit response data signals (hereinafter referred to as response signals) in order to indicate that a signal of the global transmission has been accurately received.
FIGS. 9
a
to
9
c
illustrate conventional signals that are transmitted over a LAN. A description will be made assuming that five fire receivers are connected to the LAN in
FIGS. 9
a
to
9
c
.
FIG. 9
a
shows that each fire receiver independently transmits a response signal to a fire receiver #
1
in response to a global fire signal that is transmitted by the fire receiver #
1
designating all the other fire receivers as destinations of transmission. In this case, five signals (one fire signal and four response signals) are transmitted over the LAN.
FIG. 9
b
shows that the fire receiver #
1
transmits a global fire signal and then a fire receiver #
2
also transmits a global fire signal. Here, a fire signal is given priority over a response signal. Thus, the tire signal is transmitted by the fire receiver #
2
before all the fire receivers finish transmitting response signals in response to the fire signal transmitted by the fire receiver #
1
. Then, since there is not specifically any order of priority for each response signal, response signals responding to the fire signal transmitted by the fire receiver #
2
may be transmitted earlier than response signals responding to the fire signal transmitted by the fire receiver #
1
. In this case, ten signals (two fire signals and eight response signals) are transmitted over the LAN.
FIG. 9
c
shows that each fire receiver transmits a response signal in response to each global fire signal transmitted by each of the five fire receivers. In this context, for simplicity of a description, each response signal is transmitted to the LAN in good order. However, since there is not specifically any order of priority for each response signal actually as described above, each response signal may not be transmitted in good order. In this case, twenty-five signals (five fire signals and twenty response signals) are transmitted over the LAN.
In addition, a repeater of the conventional fire alarm system cannot cause controlled apparatuses such as area sound apparatuses and smoke preventing and exhausting apparatuses to be driven by a power source superimposed over a signal line from a fire receiver. Therefore, the repeater receives an activation signal transmitted by a fire receiver, causes a relay to operate based on the activation signal and supplies an external power to the controlled apparatuses, thereby activating the controlled apparatuses.
In addition, the repeater of the conventional fire alarm system is provided with a disconnection monitoring circuit or the like in order to detect disconnection of a control line to which the controlled apparatuses are connected. For example, in the disconnection monitoring circuit, resistors are connected in parallel on the controlled apparatus side, a micro-current is always flown to the control line and disconnection is detected according to a variation of the current, whereby disconnection of the control line is monitored.
However, in recent years, since buildings have become larger and more complicated, if a building is divided into two ridge sections, for example, it is sufficient to monitor a fire in each ridge section in many cases when a plurality of fire receivers are installed to configure a fire alarm system. Thus, since fire detection information is shared by all fire receivers connected to a LAN in the conventional fire alarm system, for example, an occurrence of a fire in one ridge section may be notified to the other ridge section and the other ridge section where a fire has not occurred is carelessly disordered.
In addition, as buildings become larger, it is likely that controlled apparatuses such as smoke exhausting outlets and smoke exhausting fans and a series of fire doors are connected to different fire receivers. However, in the conventional fire alarm system, since the linkage of the controlled apparatuses to an issue of an alarm of a fire sensor is made by the unit of a fire receiver, the controlled apparatuses cannot operate in correspondence with the issue of the alarm by the fire sensors among different fire receivers.
In addition, here, it is assumed that, for example, sixty-four fire receivers are connected to each other by a LAN. When one fire receiver transmits a global fire signal, the remaining sixty-three fire receivers transmit response signals responding to the fire signal (the total number of signals is sixty-four). subsequently, when another fire receiver transmits a global fire signal, the remaining sixty-three fire receivers also transmit response signals. In this way, if all the fire receivers transmit fire signals one after another, the total of 4096 (=64×64) signals are exchanged over the LAN. Actually, when an alarm is sounded to warn a fire, it is normally for an area where an issue of an alarm is required but all alarms may be sounded all at once if necessary. In this case, a state of signals over the LAN is the same as the above-mentioned state.
Each fire receiver is set such that a signal of fire information is given priority over other signals in transmission even among such a large volume of signals. However, if a large volume of signals is transmitted, since it is highly likely that signals collide with each other over the LAN and data is collapsed, re-transmission processing of signals is required. In addition, processing after receiving the signals is complicated. Due to such useless signals, a fire receiver satisfying a processing capacity that allows for a worst result is required.
In addition, the repeater of the conventional fire alarm system causes the relay to operate, thereby supplying an external power to controlled apparatuses to activate the controlled apparatuses. However, operation of a relay contact is not detected because it is assumed that the contact normally operates when the relay is caused to operates
Thus, if the relay contact is not in operation in spite of the fact that the relay is caused to operate, there is a problem where it is likely that controlled apparatuses are not actually activated in a state in which a fire receiver determines that the controlled apparatuses are activated.
Therefore, it is possible to confirm operation of the relay by separately providing a circuit for confirming operation of a relay and using the circuit to monitor a variation of a voltage or the like on the controlled apparatus side at the time when the relay is caused to operat
Hishino Kouichi
Oki Takahiro
Onji Munehiro
Sakihara Makoto
Yamaguchi Yasuo
Nohmi Bosai Ltd.
Pope Daryl
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