JP2012215975A - Fire alarm equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide fire alarm equipment capable of suppressing the deterioration of a control signal by feeding more current to a sensor line during a communication.SOLUTION: Fire alarm equipment having an ON/OFF type fire sensor 30 for feeding an alarm current to a sensor line 1 by switching when a fire is sensed and a fire receiver 10 or a sensor relay which is connected to the fire sensor 30 through the sensor line 1 and allows the fire sensor 30 to perform a predetermined operation by outputting a control signal to the sensor line 1 is provided with a reception resistor 20 which increases the current flowing to the sensor line 1 by reducing a current limit amount during communication as compared to when not communicating.

Description

  The present invention relates to a fire alarm facility.

  As a conventional fire alarm system, for example, it is connected to an on / off type fire detector that switches when a fire is detected and sends a notification current to the sensor line, and outputs a control signal to the sensor line. Then, there are those equipped with a fire receiver or a repeater that causes the fire detector to perform a predetermined operation (see, for example, Patent Document 1).

JP 2007-65708 A

The fire receiver or repeater of such a fire alarm facility limits the current that can flow through the sensor line to the minimum necessary, and limits the alarm current when the on-off fire detector detects a fire. Current consumption is suppressed.
However, when the current that can be passed through the sensor line is limited, if the amount of restriction is large, there is a problem that the control signal deteriorates due to the line capacity of the sensor line.

  The present invention has been made in order to solve the above-described problems, and provides a fire alarm system that can suppress deterioration of a control signal by flowing a large amount of current in a sensor line during communication.

  The fire alarm system of the present invention is connected to an on / off type fire detector that switches when a fire is detected and sends a notification current to the sensor line, and is connected to the fire detector via the sensor line. A fire alarm or relay device that outputs a control signal to the line to cause the fire detector to perform a predetermined operation; in the fire alarm facility, the fire receiver or relay device is in communication Current limiting means for reducing the current limiting amount and increasing the current flowing through the sensor line as compared to when not.

  In the fire alarm system of the present invention, the current limiting means includes a receiving resistor for converting a current flowing through the sensor line into a voltage.

  In the fire alarm facility of the present invention, a plurality of the receiving resistors are connected in series, and at least one of the receiving resistors is connected to a switching element in parallel with the receiving resistor, and the fire receiver or the relay is During communication, the number of the switching elements that are in the on state is increased more than when communication is not being performed, and the resistance value of the reception resistor is decreased to reduce the current limiting amount.

  Further, in the fire alarm facility of the present invention, a plurality of the receiving resistors are connected in parallel, and at least one of the receiving resistors is connected with a switching element in series with the receiving resistor, and the fire receiver or repeater is During communication, the number of the switching elements that are in the on state is increased more than when communication is not being performed, and the resistance value of the reception resistor is decreased to reduce the current limiting amount.

  In the fire alarm system according to the present invention, the current limiting means is a constant current circuit provided in the detector line between the fire receiver or relay and the fire detector.

  The fire alarm system according to the present invention reduces the current limiting amount of the current limiting means during communication and allows more current to flow than when not during communication. Therefore, it is possible to quickly reduce the charge accumulated in the line capacitance of the sensor line, or to accumulate the charge quickly and suppress the deterioration of the control signal.

  Further, in the fire alarm facility of the present invention, the current limiting means uses a receiving resistor that converts the current flowing through the sensor circuit into a voltage, so that the cost for producing the above effect is small. Have.

  In the fire alarm system of the present invention, a plurality of the receiving resistors are connected in series, and a switching element is connected in parallel with the receiving resistor to at least one of the receiving resistors. For this reason, when a plurality of receiving resistors having different resistance values are used, an effect that the degree of freedom of the resistance value of the receiving resistor is increased by switching the switching element can be achieved.

  In the fire alarm system of the present invention, a plurality of the reception resistors are connected in parallel, and a switching element is connected in series with the reception resistor to at least one of the reception resistors. For this reason, when a plurality of receiving resistors having different resistance values are used, an effect that the degree of freedom of the resistance value of the receiving resistor is increased by switching the switching element can be achieved.

  In addition, the fire alarm system of the present invention includes current limiting means that is a constant current circuit. As a result, since the current sent from the repeater to the fire detector can be limited, the current can be controlled without depending on the voltage fluctuation.

It is a schematic block diagram which shows the fire alarm equipment (P type) in Embodiment 1 of this invention. It is a schematic block diagram which shows the fire alarm equipment (R type) in Embodiment 1 of this invention. It is a circuit diagram of the fire alarm facility in Embodiment 1 of the present invention. It is a wave form diagram which shows an example of signal transmission with the repeater for detectors of the fire alarm equipment and fire detector in Embodiment 1 of this invention. It is a figure which shows the pulse which represents the relationship between the address and slot of the signal transmission of the relay device for detectors of a fire alarm facility and fire detector in Embodiment 1 of this invention, and the normality and abnormality of a fire detector. It is the schematic of the voltage waveform of the sensor circuit | line in communication of the fire alarm equipment in Embodiment 1 of this invention. It is a circuit diagram of the fire alarm facility in Embodiment 2 of the present invention. It is a circuit diagram of the fire alarm facility in Embodiment 3 of the present invention.

  Hereinafter, the fire alarm system of the present invention will be described in detail with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a schematic configuration diagram showing a fire alarm facility (P type) according to Embodiment 1 of the present invention.
As shown in FIG. 1, a plurality of fire detectors 30 are connected to the fire receiver 10 via a sensor line 1, and a termination resistor 25 is provided at the end of the sensor line 1. In addition, even if there is not more than one fire detector 30, at least one fire detector 30 is sufficient, and it differs depending on the installation environment. Although only one sensor line 1 is shown, the fire receiver 10 includes a plurality of sensor lines 1.

  The fire sensor 30 is an on / off type sensor that is turned on when a fire is detected. In addition, it monitors its own internal failure, and upon receiving a control signal (status information return command) from the fire receiver 10, returns its own status (normal, failure).

  The fire receiver 10 detects a fire signal (ON) from the fire detector 30 and gives a fire alarm. Further, in a normal state, it is determined whether or not the terminating resistor 25 is connected to monitor whether the sensor line 1 is disconnected.

FIG. 2 is a schematic configuration diagram showing the fire alarm facility (R type) in the first embodiment of the present invention.
Various terminal devices are connected to the fire receiver 15 via the signal line 2. As terminal equipment, photoelectric analog sensor 31, thermal analog sensor 32, addressable transmitter 33, sensor repeater 11 (relay device in the present invention), bell repeater 12, and smoke prevention control repeater 13 and the like are connected, and the fire receiver 15 communicates with the terminal device.

At least one fire detector 30 and a termination resistor 25 are connected to the sensor repeater 11 via the sensor line 1 and the termination. The detector repeater 11 performs the same processing on the fire detector 30 as the above-described fire receiver 10 of the fire alarm facility (P type) in FIG.
The bell repeater 12 is connected to a bell 40 that operates in the event of a fire. Further, the fire prevention door 50, the smoke exhauster 51, the shutter 52, and the leaning wall 53 that operate in the event of a fire are connected to the smoke prevention control repeater 13.

  With such a configuration, the fire receiver 15 collects information from various sensors and the like installed in various predetermined locations, and operates the bell 40 and the fire door 50 according to the information. Etc.

  As the fire alarm system of the first embodiment, either the P type in FIG. 1 or the R type in FIG. 2 may be used. In the following description, the fire alarm system (P type) in FIG. 1 is used. An example will be described. When the fire alarm system (R type) of FIG. 2 is used, the sensor repeater 11 performs the role of the fire receiver 10 of FIG. 1, so that the fire receiver 10 in the following description is replaced with the sensor repeater 11. That's fine.

FIG. 3 is a circuit diagram of the fire alarm facility according to Embodiment 1 of the present invention. FIG. 3A is an overall circuit diagram of the fire alarm facility, and FIG. 3B is a diagram illustrating a part of the circuit in the fire detector 30.
As shown in FIG. 3A, the fire receiver 10 includes a control unit 100 and is connected to the fire detector 30 via the transmission / reception unit 71. The fire detector 30 is connected in parallel as shown in FIG. 3, and the termination resistor 25 is also connected in parallel with the fire detector 30.

  Moreover, the comparator 70 is provided in the fire receiver 10, and the receiving resistor 20 is connected between one input part of the fire detector 30 and the comparator 70, and the tip is grounded. The receiving resistor 20 has a first receiving resistor 21 (receiving resistor in the present invention) and a second receiving resistor 22 (receiving resistor in the present invention) connected in series. The transistor 60 (the switching element in the present invention) is provided so that the collector and the emitter are connected to both ends of the second receiving resistor 22.

  The voltage converted from the current by the receiving resistor 20 is compared with a predetermined threshold voltage input to the other input unit in the comparator 70. And the comparison result of the comparator 70 is sent to the control part 100, and it can be detected whether the fire receiver 10 is a fire and a disconnection.

  As shown in FIG. 3B, the fire detector 30 includes a control unit 30b that controls the entire fire detector 30, a receiving unit 30a that performs transmission and reception with the fire receiver 10, and the like, a transistor 30c, and a Zener diode 30d. have. The transistor 30c is turned on by the control unit 30b in the event of a fire so that a current can flow through the Zener diode 30d.

Next, operation | movement of said fire alarm equipment is demonstrated.
In the normal state, the fire receiver 10 monitors whether the sensor line 1 is disconnected or whether a fire has occurred by comparing the threshold voltage and the input voltage with the comparator 70 as described above.
Fire and disconnection are monitored alternately by switching the threshold voltage between the disconnection threshold voltage and the fire threshold voltage. The disconnection threshold voltage is set lower than the voltage converted by the reception resistor 20 when a current flows only in the termination resistor 25, and the fire threshold voltage is determined by the termination resistor 25 and the fire detector 30 (sensor line 1). Is set higher than the voltage converted by the receiving resistor 20 when the maximum number of currents that can be connected to the current flows.
When switching to the disconnection threshold voltage and monitoring the disconnection, if the sensor line 1 is normal, a current flows through the termination resistor 25 and the voltage converted by the reception resistor 20 exceeds the disconnection threshold voltage. Therefore, the output of the comparator 70 is on.
When disconnection occurs, no current flows through the termination resistor 25, so that the voltage converted by the reception resistor 20 decreases and the input voltage to the comparator 70 decreases. When the voltage becomes equal to or lower than the disconnection threshold voltage, the output of the comparator 70 is inverted (turned off) and input to the control unit 100, and the control unit 100 detects that a disconnection has occurred.

When monitoring the fire by switching to the fire threshold voltage, if the sensor line 1 is normal, the voltage obtained by converting the current of the terminating resistor 25 and the fire detector 30 by the receiving resistor 20 exceeds the fire threshold voltage. Absent. For this reason, the output of the comparator 70 is off.
In the event of a fire, the control unit 30b of the fire detector 30 turns on the transistor 30c to pass a current through the Zener diode 30d to enter a low impedance state, and sends the alarm current (more current than during monitoring) to the sensor line. 1 flow.
When the alarm current flows, the voltage converted by the receiving resistor 20 increases, and the voltage input to the comparator 70 becomes larger than during monitoring. When the voltage exceeds the fire threshold voltage, the output of the comparator 70 is inverted (turned on) and input to the control unit 100, and the control unit 100 detects that a fire has occurred.

When the R-type fire alarm facility shown in FIG. 2 is used, the fire receiver 15 detects that a fire has occurred even when the push button of the addressable transmitter 33 is being pressed. Further, when the state information indicating that there is a fire detector 30 that has made a fire is received from the detector repeater 11, it is detected that a fire has occurred.
When the fire receiver 15 detects a fire, the fire receiver 15 issues a fire alarm and transmits a control signal to, for example, the bell repeater 12 to cause the bell 40 to ring. In addition, a control signal is transmitted to the smoke prevention control repeater 13 to operate the fire door 50 and the like to prevent the spread of fire.

Next, an operation during communication of the fire alarm facility according to the first embodiment will be described.
The transmitter / receiver 71 of the fire receiver 10 outputs a control signal to the fire detector 30 as a group of several units in order to collect the states of the fire detectors 30 connected to the fire receiver 10. The fire detector 30 operates according to the control signal, and returns its own state by the on / off operation of the transistor 30c. This operation is the same as repeating the fire state and monitoring state signals. For example, when the signal of the fire receiver 10 is output in advance (when a start pulse to be described later is output), the operation is switched to the communication mode. The control unit 10 of the fire receiver 10 receives the return of the fire detector 30 based on the output of the comparator 70.

  FIG. 4 is a waveform diagram showing an example of signal transmission between the fire receiver 10 and the fire detector 30 of the fire alarm facility according to Embodiment 1 of the present invention. FIG. 5 is a pulse representing the relationship between the address and slot of signal transmission between the fire receiver 10 and the fire detector 30 of the fire alarm facility and the normality and abnormality of the fire detector 30 according to the first embodiment of the present invention. FIG. 4 and FIG. 5 is a voltage signal (voltage waveform between the CL terminals) of the sensor line 1. In the following example, 30 fire detectors 30 are connected to the fire receiver 10 via the sensor line 1.

In FIG. 4, “parent” is the fire receiver 10, and “child” is the fire detector 30. For convenience of explanation, the parent → child waveform and the child → parent waveform are shown separately.
An individual address is given to the fire detector 30, and the fire receiver 10 groups the fire detectors 30 based on the address and collects the data of the fire detector 30 in units of 15 addresses. . At the time of data collection, a start pulse, a reference pulse, and a command CM1 are transmitted.
When data collection is started, first a start pulse is sent, and then a reference pulse is sent. The fire alarm facility is switched to a communication state when this reference pulse is sent. The reference pulse is a pulse having a basic length (for example, 4 ms) of a transmission pulse interval. The interval is a falling edge interval (a change timing from a high (Hi) to a low (Lo) and a next high to low). During the change timing).

  Although not shown in detail, the command CM1 is a control command to the fire detector 30 and indicates a 2-bit code at one falling edge interval. The combination of the edge interval and the code is, for example, 00b for 4 ms, 01b for 6 ms, 10b for 8 ms, and 11b for 10 ms. Thus, an 8-bit code (b7 to b0) is shown at four pulse intervals.

  These combinations form a polling 1 command CM1 for collecting data at addresses 1 to 15 and a polling 2 command CM1 for collecting data at addresses 16 to 30. Although not shown in detail, a selection as a control command for designating the fire detector 30, a sleep start command for setting the fire detector 30 in a sleep mode, or the like can be used. The fire detector 30 analyzes the command CM1 and recognizes the transmission content.

  Slots 0 to 14 in FIG. 4 determine the timing for transmission from the fire detector 30 to the fire receiver 10. A slot position (see FIG. 5A) is set based on polling 1 or 2 and its own address, and the fire detector 30 has a pulse indicating a code indicating normality or abnormality in the set slot (FIG. 5B). ))). For example, each fire detector 30 returns a pulse having a pulse width of 2 ms if the function is normal as a result of the test function, and returns a pulse having a pulse width of 4 ms if the function is abnormal. Then, the fire receiver 10 ends the communication state when the return from each fire detector 30 is completed.

  Using such signal transmission, the fire receiver 10 includes the control content of polling 1 or 2 in the control command CM1 and transmits it, so that the fire detector 30 connected to the detector line 1 is normal or abnormal. Can be collected individually. At the same time, the presence or absence of a response of the fire sensor 30 is determined based on the presence or absence of a pulse in each slot, and the abnormality of the fire sensor 30 is determined.

In this example, 30 fire detectors 30 are addressed to one sensor line 1. However, it is not necessary to limit the number of the fire detectors 30. Depending on the number of slots and the number of polling 1 and 2 It can be set arbitrarily.
In addition, the communication method of the fire alarm system according to the first embodiment is not limited to the above, and the signal transmission (including fire detection) between the fire receiver 10 and the fire detector 30 is performed by an on / off signal. If it is. For example, the type of signal may be distinguished not by the pulse width but by the pulse interval.

Next, the reception resistor 20 according to the first embodiment will be described.
If the resistance value of the receiving resistor 20 is too large, the voltage converted by the receiving resistor 20 when the current of the fire detector 30 and the terminating resistor 25 flows increases, and the voltage of the sensor line 1 (the voltage between the CL terminals) ) Becomes low, the operation of the fire detector 30 becomes unstable. However, if the resistance value of the receiving resistor 20 is too small, the alarm current becomes too large, so that the fire receiver 10 can operate normally even when the alarm current flows through the plurality of sensor lines 1. In addition, for example, when the power source is a battery, a large capacity battery is required. Therefore, it is necessary to select a reception resistor 20 having a resistance value as large as possible within a range in which the operation of the fire detector 30 does not become unstable.

Also, for detection of disconnection, the receiving resistor 20 should be large. The reason is that the minimum receiving resistance voltage under monitoring which is a voltage converted by the receiving resistance 20 (for example, the voltage in a state where one fire detector 30 and the terminating resistor 25 are connected) and the maximum receiving resistance voltage at the time of disconnection. This is because it is desired to increase the difference so that it can be discriminated from (for example, the voltage in a state where 30 fire detectors are connected). Thereby, it becomes possible to easily determine the disconnection. Therefore, during monitoring, the control unit 100 turns off the transistor 60 so that current flows through the first receiving resistor 21 and the second receiving resistor 22 and increases the resistance value of the receiving resistor 20.
During the monitoring as described above, the resistance value of the reception resistor 20 is increased. However, when the resistance value is large during communication, when the voltage of the sensor line 1 is changed, the line of the sensor line 1 is changed. Since the discharge and accumulation of the charges accumulated in the inter-capacitance are hindered by the receiving resistor 20, the control unit 100 turns on the voltage applied to the base of the transistor 60 so that no current passes through the second receiving resistor 22. The resistance value of the receiving resistor 20 is reduced by allowing the current to flow only through the first receiving resistor 21.
In the first embodiment, the transistor 60 is used as the switching element. However, it is sufficient that the second receiving resistor 22 can be short-circuited and can be controlled on and off, such as an FET or IGBT.

  In addition, although an example has been described in which there are two reception resistors and one switching element, it is sufficient that there are two or more reception resistors and one or more switching elements. Even when the number of reception resistors and the number of switching elements is changed from the above example, the same effect can be obtained by increasing the number of switching elements in the on state during communication compared to when communication is not being performed.

FIG. 6 is a schematic diagram of a voltage waveform between terminals of the fire detector 30 during communication of the fire alarm facility according to Embodiment 1 of the present invention.
FIG. 6A shows a state where the resistance value of the receiving resistor 20 is small and the current limit amount is small, and FIG. 6B shows a state where the resistance value of the receiving resistor 20 is large and the current limit amount is large.

In the first embodiment, during communication, the control unit 100 turns on the transistor 60 to reduce the resistance value of the receiving resistor 20, thereby reducing the current limit amount and supplying the current that can flow to the sensor line 1. increase. That is, the time constant of the circuit from the sensor line 1 to the comparator 70 can be reduced. As a result, the charge accumulated in the line-to-line capacitance of the sensor line 1 can be quickly reduced or accumulated quickly, resulting in a rectangular voltage signal having a pulse width A as shown in FIG.
On the other hand, when the control unit 100 turns off the transistor 60 to increase the resistance value of the receiving resistor 20 to increase the current limit amount and reduce the current that can be passed through the sensor line 1, the communication is performed. The degraded voltage signal is not a rectangle as shown in FIG. The pulse width in FIG. 6B is more varied than that in FIG. 6A, and for example, B1 and B2 have different pulse widths. Therefore, as shown in FIG. 5, there are cases where normal determination cannot be made when determining the type of signal based on the pulse width. This also applies to the case of performing communication for determining the signal type at the pulse interval.

Therefore, as described above, the control signal of the fire detector 30 from the fire receiver 10 and the response signal from the fire detector 30 to the fire receiver 10 are reduced by reducing the current limiting amount of the receiving resistor 20 only during communication. Can be prevented.
Further, if normal communication is attempted using a voltage signal as shown in FIG. 6B, it is necessary to widen the pulse width to reduce the influence of deterioration in order to reduce the influence of variations in the pulse width. There is. Therefore, the communication speed must be reduced. When the number of fire detectors 30 is large, high-speed communication is required, so it is particularly desirable to reduce the deterioration of the control signal as described above.

As described above, the fire alarm system according to the first embodiment includes the reception resistor 20 as a current limiting unit, and reduces the resistance value of the reception resistor 20 when the control unit 100 outputs a control signal. Reduce.
In addition, since the charge accumulated in the line-to-line capacitance of the sensor line 1 can be quickly reduced or accumulated quickly, there is an effect that the control signal does not deteriorate. Moreover, it can suppress that the communication operation | movement of the fire detector 30 becomes unstable.
Moreover, since the fire alarm system of the first embodiment has a configuration in which only the reception resistor 22 and the transistor 60 are increased as compared with the conventional one, there is a feature that there is little increase in cost for achieving the above effect.

Embodiment 2. FIG.
Next, an example in which a different configuration is used for the receiving resistor 20 used as the current limiting means will be described.
FIG. 7 is a circuit diagram of the fire alarm facility according to Embodiment 2 of the present invention. In the second embodiment, items that are not particularly described are the same as those in the first embodiment, and the same functions and configurations are described using the same reference numerals.

  As shown in FIG. 7, the first receiving resistor 21 (receiving resistor in the present invention) and the second receiving resistor 22 (receiving resistor in the present invention) are implemented on the input side of the comparator 70. Although it is the same as Embodiment 1, it differs from Embodiment 1 in the point provided in parallel. The first transistor 61 (switching element in the present invention) is provided in series with the first receiving resistor 21, and the second transistor 62 (switching element in the present invention) is in series with the second receiving resistor 22. Is provided. And the resistance value of the receiving resistor 20 can be freely switched by controlling ON / OFF of the voltage which the control part 100 gives to the base of the 1st transistor 61 and the 2nd transistor 62. FIG.

  For example, when communication is not being performed, the resistance value of the reception resistor is increased by turning on one of the first transistor 61 and the second transistor 62, and the current limit amount is increased. Reduce the current that can flow. Further, during communication, both the first transistor 61 and the second transistor 62 are turned on to lower the resistance value, reduce the current limit amount, and increase the current that can be passed through the sensor line 1. When using either the first transistor 61 or the second transistor 62, the first receiving resistor 21 and the second receiving resistor 22 having different resistance values may be used. In this case, two resistance values can be selected. In the second embodiment, each transistor is used as the first switching element and the second switching element. However, the first receiving resistor 21 and the second receiving resistor 22 such as FET or IGBT are energized. However, any device that can be turned on / off can be used.

  In addition, although an example has been described in which there are two reception resistors and two switching elements, it is sufficient that there are two or more reception resistors and one or more switching elements. Even when the number of reception resistors and the number of switching elements is changed from the above example, the same effect can be obtained by increasing the number of switching elements in the on state during communication compared to when communication is not being performed.

  As described above, in the second embodiment, the first receiving resistor 21 and the second receiving resistor 22 are provided as current limiting means, and the transistors provided in series with each other can be turned on and off. As a result, not only the same effect as in the first embodiment is obtained, but also when the first receiving resistor 21 and the second receiving resistor 22 have different resistance values, the degree of freedom of the resistance value of the receiving resistor is increased. The effect that it becomes high can be produced.

Embodiment 3 FIG.
An example using a configuration different from that of the first and second embodiments as the current limiting means will be described.
FIG. 8 is a circuit diagram of the fire alarm facility according to Embodiment 3 of the present invention. In Embodiment 3, items that are not particularly described are the same as those in Embodiment 1, and the same functions and configurations are described using the same reference numerals.

  As shown in FIG. 8, the reception resistor of the third embodiment is only the first reception resistor 21. A current limiting means 23 is provided on the current output side of the fire receiver 10. The current limiting unit 23 is a constant current circuit using, for example, a resistor and a transistor, and may be any device that can limit the current. By providing the current limiting means 23, the current sent from the detector repeater 11 to the fire detector 30 can be limited when not communicating. Further, the current limiting means 23 can control the current without depending on the voltage fluctuation.

  As described above, in the third embodiment, for example, the current limiting means 23 which is a constant current circuit is provided, and the current sent from the detector repeater 11 to the fire detector 30 can be limited. Thereby, not only the same effect as in the first embodiment can be obtained, but also an effect that the current can be controlled without depending on the voltage fluctuation can be obtained.

  DESCRIPTION OF SYMBOLS 1 Sensor line, 2 Signal line, 10 Fire receiver, 11 Sensor repeater, 12 bell repeater, 13 Smoke prevention control repeater, 15 Fire receiver, 20 Receiving resistance, 21 First receiving resistance 22 second receiving resistor, 23 current limiting means, 25 termination resistor, 30 fire detector, 30a receiving unit, 30b control unit, 30c transistor, 30d zener diode, 31 photoelectric analog sensor, 32 thermal analog sensor, 33 Addressable Transmitter, 40 Bell, 50 Fire Door, 51 Smoke Exhaust Machine, 52 Shutter, 53 Wall, 60 Transistor, 61 First Transistor, 62 Second Transistor, 70 Comparator, 71 Transceiver, 72 Power Supply, 100 Control unit.

Claims (5)

An on-off type fire detector that switches when a fire is detected and sends the alarm current to the sensor line;
A fire receiver or a relay connected to the fire sensor via a sensor line, outputting a control signal to the sensor line and causing the fire sensor to perform a predetermined operation;
In a fire alarm facility comprising:
The fire receiver or repeater includes a current limiting means for reducing a current limiting amount during communication and increasing a current flowing through the sensor line as compared with when not in communication. Notification equipment.   2. The fire alarm system according to claim 1, wherein the current limiting means includes a receiving resistor that converts a current flowing through the sensor line into a voltage. A plurality of the receiving resistors are connected in series,
A switching element is connected to the at least one receiving resistor in parallel with the receiving resistor,
The fire receiver or repeater is
3. The current limiting amount is reduced during communication by reducing the number of the switching elements that are in an on state more than when not in communication and reducing the resistance value of the reception resistor. Fire alarm equipment. A plurality of the receiving resistors are connected in parallel;
A switching element is connected to at least one receiving resistor in series with the receiving resistor,
The fire receiver or repeater is
3. The current limiting amount is reduced during communication by reducing the number of the switching elements that are in an on state more than when not in communication and reducing the resistance value of the reception resistor. Fire alarm equipment.   2. The fire alarm system according to claim 1, wherein the current limiting means is a constant current circuit provided in the sensor line between the fire receiver or relay and the fire sensor.

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