JPH0827874B2 - Fire alarm - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention connects a plurality of sensors having unique addresses between signal lines for both power source and a signal drawn from a receiver to identify and display a fire occurrence area. Fire alarm equipment.

[Prior Art] Conventionally, as this type of fire alarm device, for example, one shown in Fig. 5 is known.

In FIG. 5, reference numeral 1 denotes a receiver, and a plurality of sensors 3a to 3n having unique addresses are connected between the power / signal lines 2a and 2b drawn from the receiver 1.

The detectors 3a to 3n are equipped with a fire detector 4 that triggers an SCR for fire detection and sends an alarm current to the detector body, while the detector base detects the alarm current of the fire detector 4 on the base side. And a transmission circuit 6 for transmitting the fire detection information to the receiver 1 together with the unique address information by the address setting circuit 7 when the detection output of the current detection circuit 5 is received. A warning indicator light 8 using an LED or the like is connected between the current detection circuit 5 and the current detection circuit 5.

Therefore, for example, if the fire detection unit 4 of the sensor 3a is activated by the fire detection and an alarm current flows by the SCR trigger, the alarm indicator lamp 8 lights up and the current detection circuit 5
Generates a detection output, and a transmission signal having a frame structure including fire detection information and unique address information is transmitted from the transmission circuit 6 to the receiver 1. In the receiver 1 which receives the signal from the sensor 3a, the fire alarm is displayed from the fire information in the transmission signal and the unique address information is decoded to determine the fire occurrence area, for example, the detector address. indicate.

[Problems to be Solved by the Invention] However, in such a conventional fire alarm device, when a plurality of detectors connected between the same power source and signal line simultaneously alarm, alarm detection is performed. The current flowing through the signal line that also serves as a power source increases in accordance with the number of devices, and the voltage supplied by the line resistance lowers the sensor supply voltage.

Therefore, the clock pulse voltage for transmitting the detection information to the receiver becomes insufficient, and there is a possibility that transmission may be impossible.

[Means for Solving Problems] The present invention has been made in view of the above-mentioned problems of the related art, and when the number of sensors issued exceeds a predetermined number, stable line reception is performed without increasing the line current. An object of the present invention is to provide a fire alarm device capable of compensating for information transmission between a machine and a detector.

In order to achieve this object, in the present invention, a plurality of detectors each having a unique address are connected between the power source / signal lines drawn from the receiver, and each of the detectors maintains conduction when a fire is detected. When a fire detection unit that has a switching means (SCR, etc.) that sends an alarming current and a current detection circuit that detects the alarming current from the fire detection unit and the detection output of the current detection circuit are obtained In a fire alarm device equipped with a transmission circuit for sending a unique address signal to a receiver and displaying a detector address, in the receiver, non-report detection is detected when the number of alarm detectors reaches a predetermined value. Is provided with a control means for sending a current limiting signal by designating an address of the device, while
In each of the detectors, a current limiting circuit that limits the alarm current when a fire is detected to a constant value capable of maintaining conduction of the switching means, and the current limiting control signal from the receiver are discriminated and received by the transmission circuit. A current limiting switching circuit for switching the limiting value of the current limiting circuit to a lower value is sometimes provided.

[Operation] In the fire alarm device of the present invention having such a configuration, the alarming of a predetermined number of sensors connected to the same line from the receiver, for example, the alarming of two sensors is performed. When detected,
When the current limit control signal is sent by specifying the address of another sensor, the current limit control signal from the receiver can be identified and received for the sensor in the non-reporting state at this time. The limit value of the circuit is switched to a predetermined value less than or equal to the steady monitoring current.

Therefore, even if a fire detection is performed by the sensor whose current limit value has been switched to a lower value, the line current between the receiver and the receiver hardly increases, and the line current depending on the number of sensor issuances so far. Since the line current is maintained, the sensor supply voltage due to the line resistance does not drop further, and it is possible to ensure the information transmission between the receiver and the sensor.

On the other hand, even if the detector whose current limit value has been switched to a lower value detects a fire and triggers the SCR provided in the fire detection unit, the SCR cannot be held in the conductive state due to the current limit. However, while the fire detection output is being obtained, the SCR
Since the current is conducted, the current detection circuit can provide the transmission circuit with the minimum current detection output required for signal transmission to the receiver, and it is impossible to maintain the SCR continuity and turn on the alarm indicator lamp due to current limitation. The fire detection information and the address information can be normally transmitted from the sensor to the receiver.

Furthermore, the warning indicator lamp cannot be turned on when a fire is detected due to current limitation, but the warning indicator lamp of the sensor that was issued before the current limit value was switched is already on, so any further indicator lamps will be turned on. If you do not do this, no special problem will occur.

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

In FIG. 1, reference numeral 1 is a receiver, and a plurality of addressable sensors 3A, 3B, ..., 3N having unique addresses are connected between the power / signal lines 2a, 2b drawn from the receiver 1. .

The receiver 1 is provided with a receiver circuit 9, which receives and decodes a transmission signal including fire detection information and unique address information transmitted by a fire detection by any of the addressable sensors 3A to 3N, and outputs the reception signal to the control circuit 10. The control circuit 10 decodes the fire detection information and the unique address information, and the alarm display section
The fire alarm and fire alarm display will be displayed on 11 and the decoded sensor address will be displayed. Further, when it is determined that the number of alarm detectors has reached a predetermined number, the control circuit 10 sends a current limit control signal by designating the unique address of the addressable sensor other than the alarm detector by the transmitter circuit 12. Has a control function.

The control function of the control circuit 10 which sends out the current limit control signal is such that, when the alarm of two addressable sensors is detected, the current limit is performed by designating the unique address of another non-reportable addressable sensor. Control signals will be sent out.

FIG. 2 shows the addressable sensors 3A to 3N shown in FIG.
FIG. 3 is a circuit block diagram showing an embodiment of the present invention. In this embodiment, a plurality of sensors installed in the same warning area are grouped, and only a specific sensor among them is given a unique address. As an example, a case where a plurality of other sensors are cascade-connected as a child sensor to a parent sensor as a child sensor is shown.

In FIG. 2, reference numeral 3 is a parent sensor having a function as an addressable sensor, and terminals 13a and 13 of the parent sensor 3 are provided.
The power / signal lines 2a and 2b from the receiver 1 are connected to b, and there is no unique address between the power / signal lines 15a and 15b separately drawn from the terminals 14a and 14b of the parent sensor 3. A plurality of child detectors 16A to 16N using ordinary detectors are connected in parallel, and a terminating resistor 17 for detecting disconnection is connected to the ends of the power / signal lines 15a and 15b.

The parent sensor 3 as an addressable sensor is set by the current detection circuit 5 that detects the alarm current caused by the fire detection of the fire detection unit 4, and the address setting circuit 7 when the detection output of the current detection circuit 5 is obtained. A transmission circuit 6 that sends the generated unique address information to the receiver together with the fire detection information, and a warning indicator lamp 8 that is driven to light by the warning current of the fire detection unit 4 are provided. A resistor R7 is connected in parallel to the alarm indicator lamp 8 for preventing lighting and protection during normal monitoring.

In addition to this, in the present invention, a current limiting circuit 18 is newly provided so that the current limiting circuit 18 can keep the SCR of the fire detection unit 4 conducting the alarm current when a fire is detected and the alarm indicator lamp 8 Has a constant current function that limits the light to a fixed value, for example, 6 mA.

Here, the alarm indicator lamp 8 of the parent sensor 3, the current limiting circuit 18,
The current detection circuit 5, the transmission circuit 6 and the address setting circuit 7 are incorporated in the detector base, while the fire detection unit 4 is provided in the detector body which is detachable from the detector base. That is, the fire detection unit 4 provided in the sensor body is detachably and mechanically and electrically attachable to the (+) side fitting terminals 19a, 19b and the (-) side fitting terminal 20 of the sensor base. When the main body of the sensor which is connected and has the fire detection unit 4 is removed from the sensor base, the fitting terminals 19a and 19b are disconnected from each other, and the power supply to the sensor base built-in circuit is cut off.

On the other hand, the signal line 15 that also serves as a power source, to which the slave detectors 16A to 16N are connected
The connection of the a and 15b to the connection terminals 14a and 14b is such that the line on the fitting terminal 19b side is connected to the (+) side connection terminal 14a by the signal line, while the connection terminal 14b is connected to the warning indicator lamp 8 And the current limiting circuit 18 are connected. Therefore, the fire detection unit 4 of the parent sensor 3 and the child detectors 16A to 16N are connected in parallel to the current limiting circuit 18 of the parent sensor 3, and the fire detection unit 4 of the parent sensor 3 or the child detection unit 16A to 16N. Current limiting circuit even if any of the detectors 16A to 16N is activated by a fire detection and sends a warning current
The current will be limited by 18.

The current limiting circuit 18 provided in the parent sensor 3 is a transistor
A constant current circuit is configured by Tr1, Tr2 and resistors R1, R2, R3. In the current limiting circuit 18, the transistor Tr2 is turned off and the transistor Tr1 is turned on in the steady monitoring state.
The steady monitoring current of 0.7mA is flowing. Power supply signal line 2
The current that enters the current limiting circuit 18 via a, the fitting terminals 19a and 19b, the fire detection unit 4, the fitting terminal 20, and the warning indicator lamp 8 passes through the resistor 3 of the current limiting circuit 18 and turns on the transistor Tr1. Then, the transistor Tr2 is turned off, and the current flows from the resistor R2 to the power / signal line 2b. Therefore, a constant monitoring current of 0.7 mA flows through the resistors R4 and R5. On the other hand, when the fire detection part 4 of the parent detector 3 or any of the child detectors 16A to 16N is activated by the fire detection and the alarm current is flown, the transistor Tr
1 and Tr2 are turned on to perform constant current operation, and the current limit value at this time is I = VBE / R2, where VBE is the base-emitter voltage of the transistor Tr1.

The current detection circuit 5 provided subsequent to the current limiting circuit 18 is a voltage comparator including a transistor Tr3 and resistors R4, R5, R6, and receives a voltage input according to the current value determined by the current limiting circuit 18 and receives the resistance R4. And R5 to divide the transistor
The divided voltage is input to the base of Tr3. For this reason, in the steady monitoring state, the impedance of the fire detection unit 4 is sufficiently larger than that of the current limiting circuit 18, and the output voltage from the current limiting circuit 18 is low, so the transistor Tr3 is off, and a warning is issued by a fire detection. When a constant current, which is determined by the constant current operation of the current limiting circuit 18, flows due to the current, the impedance of the fire detection unit 4 becomes sufficiently smaller than that of the current limiting circuit 18, the input voltage increases, and the transistor Tr3 turns on.

The collector output of the transistor Tr3 of the current detection circuit 5 is connected to the input terminal IN of the transmission circuit 6, and in the steady monitoring state where the transistor Tr3 is off, the input terminal IN
Is set to the H level through the resistor R6, and when the transistor Tr3 is turned on due to the detection of fire, the input terminal IN is pulled to the L level, and the L level of the input terminal IN pulls the transmission circuit 6 to the address setting circuit 7 The fire detection information is transmitted to the receiver 1 together with the unique address information set by.

Further, the transmission circuit 6 receives the current limit control signal sent from the receiver 1 shown in FIG. 1, and sets the output terminal OUT to the L level when the received signal matches its own unique address. The output terminal OUT of the transmission circuit 6 that generates a control output for is connected to the collector of the transistor Tr2 provided in the current limiting circuit 18, and the output terminal OUT of the transmission circuit 6 is output.
Is in high impedance in the steady monitoring state, the current limiting circuit 18 can normally perform the current limiting operation. On the other hand, when the output terminal OUT of the transmission circuit 6 is set to the L level by the identification reception of the current limiting control signal from the receiver, the transistors Tr1 and Tr2 of the current limiting circuit 18 are forcibly turned off and further compared with the resistor R1. Since the resistance value of the resistor R3 is sufficiently large, the current limiting circuit 18 is switched to a current limiting state in which a monitoring current in a steady monitoring state, for example, a monitoring current lower than 0.7 mA, for example, a monitoring current of 0.5 mA flows.

FIG. 3 is a circuit block diagram showing an embodiment of the fire detection unit 4 of the parent sensor 3 shown in FIG. The child detectors 16A to 16N cascade-connected to the parent detector 3 have the same configuration. Further, the child detectors 16A to 16N include, as a representative of 16A, the fire detection unit 4 and the resistor R7 shown in FIG.
Is provided in parallel with the warning indicator lamp 8.

In FIG. 3, a fire detection circuit 21 is provided in the fire detection unit 4. For example, when a photoelectric smoke detection mechanism is taken as an example, scattered light of inflowing smoke due to intermittent pulse emission is detected and a light reception output is obtained. It is configured to generate a fire detection output when a predetermined level is reached. That is, the fire detection circuit 21 will intermittently generate a fire detection output when a fire is detected. The output of the fire detection circuit 21 is SCR22 as a switching means.
Is given to the gate of the SCR22, the SCR22 is held in conduction by being triggered by the detection output of the fire detection circuit 21, and the alarm current is made to flow by holding the SCR22 in conduction. SC at this time
As shown in FIG. 2, the alarm current due to the continuity holding of R22 is limited to a constant current capable of holding the SCR22 in continuity and lighting the alarm indicator lamp 8 by the current limiting circuit 18, for example, 6 mA. .

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

Of the plurality of addressable sensors 3A to 3N connected to the receiver 1 of FIG. 1, for example, the addressable sensor at time t1 as shown in the timing chart of FIG.
If a fire is detected at 3A, the addressable sensor 3A has a current limiting circuit 18 as shown in FIG. 2, so the alarm current of the fire detecting unit 4 is limited to 6mA, and at the same time the addressable sensor is detected. Receiver 1 from 3A transmission circuit 6
A transmission signal including the fire detection information and the unique address information is sent to. This transmission signal is received by the receiving circuit 9 of the receiver 1.
The fire detection information is received by the control circuit 10, the fire display is displayed on the alarm display section 11, and the address information is determined to display the sensor address.

Next, if the addressable sensor 3B detects a fire at time t2 in Fig. 4, the alarm current is 6 mA.
Limited to the receiver 1, and the receiver 1 has an addressable sensor.
The transmission signal from 3b is received, and the sensor address is displayed on the alarm display unit 11.

Here, since the control circuit 10 of the receiver 1 has the function of transmitting the current limit control signal to the other non-reporting detectors with two reporting sensors, The current limit control signal is sent by designating the unique addresses of the addressable sensors 3C to 3N other than the notified addressable sensors 3A and 3B.

In the other non-reporting addressable sensor which has received the current limit control signal from the receiver 1, as shown in FIG. 2, the current limit control signal from the receiver 1 is transmitted to the transmission circuit 6 as shown in FIG. When the identification signal is received at, an L level output is generated at the output terminal OUT, and the transistors Tr1 and Tr2 of the current limiting circuit 18 are forcibly turned off. Therefore, in the non-reporting addressable sensor, for example, the sensor 3N shown in FIG. The steady-state monitoring current of 0.7 mA so far is limited to a lower steady-state monitoring current of 0.5 mA. Therefore, even if the third or later sensor is issued, the line currents of the power supply / signal lines 2a and 2b from the receiver 1 are maintained at the alarm currents of two alarm detectors. Since the line current does not increase, the increase in the voltage drop due to the line resistance can be suppressed, and the information transmission between the reporting sensor and the non-reporting sensor can be guaranteed.

Next, the operation when the fire detection is performed by the non-reporting sensor whose current limit value is switched to a lower value by the current limit control signal from the receiver 1 is as follows.

It is assumed that the current limit value is switched to a lower value by the non-reportable addressable sensor 3N at time t2 in FIG. 4 and the fire is detected at the subsequent time tn. At this time, the fire detection unit 4 intermittently produces a fire detection output as shown in FIG. 4, and the SCR22 cannot maintain conduction due to current limitation, but while the fire detection output is obtained, It will be conducted. As a result, while the SCR22 is conducting due to the fire detection output, the transistor Tr3 of the current detection circuit 5 shown in FIG.
N can be at L level.

Here, L of the input terminal IN required for the transmission operation of the transmission circuit 6
If the level pull-in time is ΔT2, ΔT2 = about 20 ms is required to prevent noise and chattering of mechanical contacts.

Therefore, the signal input period Δ required for the transmission operation of the transmission circuit 6
For T2 = 20ms, fire detection output occurrence time ΔT1 is
By setting T1 = 40ms long, SCR22 due to current limitation
The fire detection information and the address information can be normally transmitted to the receiver 1 even if the continuity of the above can not be maintained.

Further, when a fire is detected in the sensor that has been switched to the current limiting state of a lower current value by the current limiting control signal from the receiver 1, the warning indicator lamp 8 cannot be turned on due to the current limiting, The alarm indicator lamp is used for re-checking the detector that has been operated when the fire is received, so it is necessary to turn on the alarm indicator lamp 8 up to the second alarm, but There is no particular problem even if the alarm indicator light is turned on after the report because there is no need to check the site.

In the above embodiment, the current limit control signal is sent to the non-reporting sensor when the receiver 1 detects the two sensor reports. The number of alarms issued by the sensor that sends the signal can be appropriately determined.

Further, in the above embodiment, as shown in FIG.
The addressable sensor having a configuration in which a plurality of child sensors 16A to 16N are cascade-connected to the parent sensor 3 has been taken as an example.
Of course, it may be a single addressable sensor having no child sensor.

[Effects of the Invention] As described above, according to the present invention, when a receiver determines that the number of reported sensors has reached a predetermined number, another non-reported sensor address is designated. In the sensor that sent out the current limit signal and identified and received this current limit control signal, the fire alarm current is set to a constant current, for example, the current value at which conduction of the switching means such as SCR provided in the fire detector can be maintained. Since the current limiting circuit to be limited is switched to a limit value lower than the steady monitoring current, the line current from the receiver to the sensor does not increase any more even if the number of sensor issuance exceeds a predetermined number. By suppressing the drop of the sensor supply voltage due to resistance to a predetermined value, it is possible to guarantee the information transmission function between multiple sensors connected to the same line and the receiver, and multiple addressable sensors are installed in the receiver. Fire alarm connected The reliability of the device can be further improved.

[Brief description of drawings]

1 is a block diagram showing an embodiment of the present invention; FIG. 2 is a circuit block diagram showing an embodiment of the addressable sensor shown in FIG. 1; FIG. 3 is a diagram showing the fire detection unit shown in FIG. 4 is a circuit block diagram showing an embodiment; FIG. 4 is a timing chart showing the operation of the present invention; and FIG. 5 is an explanatory diagram of a conventional device. 1: Receiver 2a, 2b: Power line signal line 3A to 3N: Addressable sensor 3: Parent sensor 4: Fire detector 5: Current detection circuit 6: Transmission circuit 7: Address setting circuit 8: Warning indicator light 9 : Reception circuit 10: Control circuit 11: Alarm display section 12: Transmission circuit 13a, 13b, 14a, 14b: Terminals 15a, 15b: Power supply / signal line (for child sensor) 16A to 16N: Child sensor 17: Terminal resistor 18 : Current limiting circuit 19a, 19b, 20: Mating terminal 21: Fire detection circuit 22: SCR (switching means) Tr1 to Tr3: Transistor R1 to R6: Resistor

Claims (1)

[Claims] 1. A switching system in which a plurality of detectors each having a unique address are connected between a signal line for power supply and a signal line drawn from a receiver, and each of the detectors is kept conductive when a fire is detected and a warning current is passed. A fire detection unit having a means, a current detection circuit for detecting a warning current from the fire detection unit, and a detector which sends a unique address signal to the receiver when the detection output of the current detection circuit is obtained In a fire alarm device having a transmission circuit for displaying an address, the receiver is provided with a current limit control signal by designating an address of a non-reporting sensor when the number of reporting sensors reaches a predetermined number. A control means for sending out is provided, and in each of the detectors, a current limiting circuit for limiting a warning current at the time of fire detection to a constant current capable of maintaining conduction of the switching means, and a current from the receiver in the transmission circuit. Restricted system Fire alarm device, characterized in that the limit value of the current limiting circuit is provided and a current limiting switching means for switching to a lower than normal monitor current value when the identified receiving a signal.