JP2992152B2 - Fire alarm system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for performing a fire test and a fire recovery in a fire receiver of a fire alarm system.

[0002]

2. Description of the Related Art In a conventional fire receiver, a fire test (a function test of a fire receiver) is performed by short-circuiting a sensor connection terminal to which a fire detector is connected by a test switch.
After the fire test is completed, the fire is restored by turning off and on the reset switch, opening the fire detector from the fire receiver, and then connecting it.

FIG. 3 is a circuit diagram showing an example of a conventional fire receiver. In this figure, a plurality of fire detectors S,... Are connected to fire detector connection terminals C, L of a fire receiver RE via a line, and a terminating resistor is connected to the end. A normally open test switch ST is provided in parallel with the fire detectors S,..., And a normally closed reset switch SR1 for restoring the fire detector S is connected between the terminal L and the fire detection circuit 10. ing.

In the fire detection circuit 10, a fire detection resistor R1 is connected in series with the fire detector S, and a time constant circuit in which a capacitor C1 and a resistor R2 are connected in series is connected in parallel with the fire detection resistor R1. , Fire detector comparator CO
MP and a fire signal holding transistor T1 are provided,
A reset switch SR2 for restoring the fire receiver RE is provided in a part of a signal holding loop formed by the fire signal holding transistor T1. The reset switch S
R1 and SR2 are rebound switches, which are turned off as long as the switch is kept pressed, and turned on when the switch is released.
The reset switches SR1 and SR2 are linked with each other.

In the above conventional example, to perform a fire test, a test switch ST is turned on to generate a pseudo state similar to the operation of the fire detectors S,. The reset switches SR1 and SR2 are simultaneously turned off and then turned on, thereby restoring the fire detectors S,... And the fire receiver RE.

[0006]

In the above conventional example, the fire test cannot be performed after the fire test is performed by pressing the test switch ST, so that subsequent fire monitoring cannot be performed. It is necessary to always press the reset switches SR1 and SR2 later. Therefore, when performing a fire test, the switch operation must be performed two times.
This operation is required many times, and there is a problem that this operation is complicated.

In the above conventional example, when performing a fire test, it is necessary to provide two switches, a test switch ST and reset interlocking switches SR1 and SR2, so that a large space for the fire receiver is required. There is a problem of doing.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fire alarm system capable of easily operating a switch when performing a fire test and reducing the installation space of a switch required for performing a fire test. Is what you do.

[0009]

SUMMARY OF THE INVENTION The present invention comprises a switching contact,
A normally-closed contact that is always in contact with this switching contact, and a rebound switch having a normally-open contact that contacts the switching contact only when the switching contact is operated, and a switching contact of the rebound-type switching switch. The normally open switch section consisting of the normally open contacts is connected in parallel with the fire detector, and when the reset circuit receives a trigger from the normally closed contacts of the rebound switch, the reset circuit restores the fire receiver It is to let.

[0010]

According to the present invention, it is possible to execute a fire test and a fire recovery or a single fire recovery by simply releasing the switch after pressing the rebound type changeover switch. In equipment, switch operation when performing a fire test and fire recovery is easy,
In addition, it is possible to reduce the installation space for switches required for performing a fire test and fire recovery.

[0011]

FIG. 1 is a block diagram showing an embodiment of the present invention.

In this embodiment, a line is connected to the fire detector connection terminals C and L of the fire receiver RE1, and a plurality of fire detectors S are connected via this line. Is connected. The fire detector S includes a fire detector having a self-holding function, such as a smoke detector, and a fire detector having no self-holding function, such as a heat detector.

The fire receiver RE1 includes a rebound type changeover switch SW, a fire detection circuit 11, a fire alarm flicker circuit 21, a disconnection detection circuit 22, a disconnection flicker circuit 23, a silence circuit 24, a buzzer Z, And a reset circuit 30. The difference between the fire receiver RE1 of the above embodiment and the fire receiver RE of the conventional example shown in FIG.
A single rebound switch SW is provided in place of the two switches of the test switch ST, and a normally open switch unit composed of a changeover contact and a normally open contact of the changeover switch SW has a fire detector S and The point that they are connected in parallel and the point that the reset circuit 30 is newly provided.

The rebound type changeover switch SW includes a changeover contact, a normally closed contact NC which is always in contact with the changeover contact,
The switch includes a normally open contact NO that comes into contact with the switching contact only when the switching contact is pressed, and is also referred to as a non-locking changeover switch. When the switching contact is pressed, the contact between the switching contact and the normally closed contact NC is released. Further, the resistance value of the resistor R10 is set to, for example, a resistance value equal to or lower than the impedance of a fire detector operated by a fire.

The fire detection circuit 11 includes a reset switch S
This is the same as the fire detection circuit 10 except that R2 is removed and that portion is short-circuited. That is, a time constant circuit composed of a series circuit of the capacitor C1 and the resistor R2 is connected in parallel with the fire detection resistor R1, and only when the voltage of the capacitor C1 becomes higher than a predetermined first reference voltage, A comparison circuit COMP that outputs a low signal is provided, and the first reference voltage is a voltage generated at a connection point between the resistors R3 and R4 in the voltage dividing circuit including the resistors R3, R4, and R5. . Further, the emitter of the PNP transistor T1 is connected to + VS, the collector is connected to the hot side of the fire detection resistor R1 via the collector resistor R6, and the transistor T1 is connected when the comparison circuit COMP is outputting a Low signal. , Which supplies a current substantially equal to the fire signal to the fire detection resistor R1, and is an example of a switching element that supplies a current substantially equal to the fire signal to the fire detection resistor when the comparison circuit is outputting a signal. . That is, the comparison circuit COMP outputs a High signal during monitoring and outputs a Low signal when a fire is detected.
Once a fire signal is detected, transistor T1 and resistor R
6, a fire signal is continuously supplied to the fire detection resistor R1 to hold the fire signal.

The time constant circuit composed of a series circuit of the capacitor C1 and the resistor R2, the comparator COMP, the transistor T1, and the resistor R6 form a fire signal when a fire signal flows through the fire detection resistor. 5 is an example of a fire signal holding circuit that holds a signal.

The reset circuit 30 is a circuit for restoring the fire receiver RE1 when a trigger is received from the normally closed contact NC of the rebound switch SW.
A transistor T2 for inverting the trigger pulse at
A monostable multivibrator V1 that generates a predetermined pulse at the rise of the pulse at the normally closed contact NC;
A transistor T3 for discharging the electric charge stored in the capacitor C1 when the monostable multivibrator V1 generates a pulse. The transistor T3
Is an example of a second switching element that discharges a charge stored in a capacitor when a monostable multivibrator generates a pulse.

The fire alarm flicker circuit 21 blinks the fire indicator light LF1 and intermittently sounds the buzzer Z when the comparison circuit COMP is outputting a Low signal. The disconnection detection circuit 22 includes a resistor R
Than the second reference voltage generated at the node between R4 and R5,
When the voltage of the capacitor C1 (the voltage corresponding to the voltage of the fire detection resistor R1) is low, a disconnection signal indicating a disconnection is output.
When a disconnection signal is input, the disconnection indicator LF2 blinks and the buzzer Z sounds intermittently. The silence circuit 24 includes a silence switch 24S
Is operated, the buzzer Z is prevented from sounding even if a fire signal or a disconnection signal is generated.

Next, the operation of the above embodiment will be described.

FIG. 2 is a time chart showing the operation of the above embodiment.

First, at time t0 in the time chart of FIG. 2, fire monitoring is performed, and a rebound type changeover switch S
The switching contact of W is brought into contact with the normally closed contact NC, and the fire detector S
The monitoring current and the current of the terminating resistor flow through the fire detecting resistor R1, and at the same time, charge the capacitor C1 via the resistor R2. Therefore, after the charging of the capacitor C1 is completed, the voltage generated across the fire detecting resistor R1 And the voltage across the capacitor C1 becomes the same, and this voltage is supplied to the negative input terminal of the comparator COMP.

On the other hand, the connection point between the resistors R3 and R4 is
Since the reference voltage is generated and the voltage between both ends of the fire detection resistor R1 is lower than the first reference voltage, the comparator COMP is set to Hig.
The h signal is output, and the fire alarm flicker circuit 21 does not operate. Further, since the comparator COMP outputs a High signal, the transistor T1 is off. Further, a second reference voltage is generated at a connection point between the resistors R4 and R5, and if no disconnection occurs, the fire detection resistor R is higher than the second reference voltage.
1 is high, the disconnection detection circuit 22 does not output a disconnection detection signal. Also, a rebound type changeover switch SW
Is kept in contact with the normally closed contact NC, the transistor T2 keeps on, the trigger is not input to the monostable multivibrator V1, and the transistor T3 keeps the off state, so that the discharge loop of the capacitor C1 is formed. Not done.

The time t1 during the fire monitoring
When the tester presses the changeover contact of the rebound type changeover switch SW, the changeover contact leaves the normally closed terminal NC and the normally opened terminal N
Contact O. As a result, the fire test is started, that is, the resistor R10 is connected between the terminals C and L, the current of the fire detection resistor R1 increases, the charge amount of the capacitor C1 increases, and the fire exceeds the first reference voltage. The voltage across the detection resistor R1 increases, and the comparator COMP outputs a low signal.

When the comparator COMP outputs a low signal, the fire indicator light LF1 blinks at about 1 Hz, the buzzer Z sounds intermittently in synchronization with this, and the transistor T
1 turns on, and a current flows through the fire detection resistor R1 via the resistor R6, so that the fire receiver RE1 is maintained in a fire state.

After the tester confirms the fire alarm state, at time t2, when the tester releases the changeover contact of the rebound type changeover switch SW, the changeover contact leaves the normally open terminal NO and contacts the normally closed terminal NC. I do. As described above, since the switching contact returns to the normally closed terminal NC, the voltage of the normally closed terminal NC sharply increases, and a trigger is generated.
2 to the monostable multivibrator V1, and outputs a positive pulse for a fixed time. While the positive pulse is being output, the transistor T3 is turned on, and the electric charge of the capacitor C1 is discharged via this transistor. As a result, the voltage of the negative input terminal of the comparator COMP becomes lower than the first reference voltage.
A signal is output, the fire alarm and the fire display are stopped, the transistor T1 is turned off, and the holding of the fire state is released.

In the above embodiment, during the fire monitoring, the fire test and the fire recovery can be executed by pressing and releasing the rebound switch SW when the switch is pressed. Very easy. Further, in the above embodiment, the test switch ST of the conventional example and the interlocking type reset switch SR
It is sufficient to provide a single rebound switch SW instead of the two switches 1 and SR2, so that the installation space for the switches required for performing the fire test and the fire recovery can be reduced.

At time t3, if a fire occurs, the fire detector S operates and the terminals C, L
The voltage between them decreases, the current of the fire detection resistor R1 increases,
The amount of charge of the capacitor C1 also increases, and the voltage across the fire detection resistor R1 becomes higher than the first reference voltage.
OMP outputs a Low signal, and the fire indicator LF1
Hz, the buzzer Z sounds intermittently in synchronism with this, the transistor T1 is turned on, and a current flows through the fire detection resistor R1 via the resistor R6, so that the fire receiver RE1 is held in a fire state. You.

At time t4 when the fire ends, the switching contact of the switch SW is pressed for a short time to recover the fire. By pressing this switching contact, the switching contact leaves the normally closed terminal NC and comes into contact with the normally open terminal NO. As a result, the resistor R10 is connected in parallel with the fire detector S, so that the fire detector S recovers from the fire. In other words, if the fire detector S has a self-holding function such as a smoke detector, a transistor is built in the fire detector S, and the transistor self-holds a fire signal simultaneously with the detection of a fire. As long as a voltage equal to or higher than a predetermined voltage is supplied to the voltage between both ends of the fire detector S, the fire detector S maintains the operating state by the above self-holding. Therefore, the fire detector S is restored to the fire monitoring state.

Then, after the elapse of the short time, that is, at time t5, the switching contact connected to + VS returns to the normally closed terminal NC, so that a trigger is generated at the normally closed terminal NC, and this trigger is generated by the transistor T2. To the monostable multivibrator V1, and the monostable multivibrator V1 outputs a positive pulse for a certain time. While the positive pulse is being output, the transistor T3 is turned on, and the electric charge of the capacitor C1 is discharged via the transistor T3. As a result, the voltage of the negative input terminal of the comparator COMP becomes lower than the first reference voltage.
MP outputs a High signal, the buzzer Z sounds, the indicator lamp LF1 stops blinking, and the transistor T1
Turns off, the fire state is released, and the fire receiver RE1
Recovers from fire.

In the above embodiment, after the fire alarm is issued, the fire recovery can be executed by pressing the rebound switch SW for a short time and then releasing the switch. Therefore, the switch operation for fire recovery can be performed. Very easy.

In the above embodiment, the rebound switch SW is such that when the switching contact is pressed, the switching contact comes into contact with the normally open contact NO. The contact may be in contact with the normally open contact NO. Note that the resistor R10 may be omitted (short-circuited).

Instead of the rebound switch SW, two rebound switches may be provided and used in conjunction with each other. That is, a normally-closed switch provided between the terminal C and the base of the transistor T2,
An interlocking of a normally open switch provided between the terminal C and the resistor R10 may be used instead of the rebound switch SW. In this specification, the terminal C and the base of the transistor T2 are connected to each other. A switch in which a normally-closed switch provided between the switch and the normally-open switch provided between the terminal C and the resistor R10 is also referred to as a “bounce switch”.

[0033]

According to the present invention, it is possible to execute a fire test or a fire recovery by pressing a rebound type changeover switch and then releasing the switch. It is easy to operate the switches when performing a fire test and fire recovery, and it is sufficient to provide a single rebound switch SW instead of the two switches conventionally used.
This has the effect of reducing the installation space for switches required for fire recovery.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention.

FIG. 2 is a time chart showing the operation of the embodiment.

FIG. 3 is a circuit diagram showing an example of a conventional fire alarm system.

[Explanation of symbols]

 S: Fire detector, RE1: Fire receiver, SW: Bounce switch, NC: Normally closed contact, NO: Normally open contact, 11: Fire detection circuit, R1: Fire detection resistor, C1: Capacitor, COMP: Comparison , 30 ... reset circuit.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-137787 (JP, A) JP-A-54-34700 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G08B 17/00

Claims (3)

(57) [Claims] 1. A fire alarm system comprising: a fire detection resistor connected in series with a fire detector; and a fire signal holding circuit for holding the fire signal when a fire signal flows through the fire detection resistor. A rebound type changeover switch comprising a changeover contact, a normally closed contact that is always in contact with the changeover contact, and a normally open contact that makes contact with the changeover contact only when the changeover contact is operated. A rebound switch in which a normally open switch section comprising a contact and the normally open contact is connected in parallel with the fire detector; a fire receiver is restored when a trigger is received from the normally closed contact And a reset circuit for causing the fire alarm system. 2. The fire signal holding circuit according to claim 1, wherein the fire signal holding circuit is connected in parallel with the fire detection resistor and includes a time constant circuit formed of a series circuit of a capacitor and a resistor; A comparison circuit for outputting a signal only when the voltage of the capacitor becomes high; and a first circuit for supplying the fire detection resistor with substantially the same current as the fire signal when the comparison circuit is outputting the signal. And a switching element. 3. The monostable multivibrator according to claim 2, wherein the reset circuit generates a pulse having a predetermined width at the rise of the pulse at the normally closed contact; and when the monostable multivibrator generates a pulse. And a second switching element for discharging the electric charge stored in the capacitor.