JP2023127407A - fire detector - Google Patents

Abstract

To provide a fire detector, even with a communication function, that can be installed in a pulse-flow type fire receiver, which is made not to be determined as a communication error failure.SOLUTION: A smoke or heat detector with a communication function that is connected to a district circuit line 2 from which a fire receiver 1 extends includes a pulse flow detection circuit 36 that detects a pulse flow and a communication circuit 35 that communicates with the fire receiver to exchange information, and deactivates the communication function of the communication circuit when the pulse flow detection circuit detects that a pulse flow is being applied to the district circuit line.SELECTED DRAWING: Figure 5

Description

FIELD OF THE INVENTION The present invention relates to fire alarm systems and fire receivers and detectors used in fire alarm systems.

There are two types of fire alarm receivers: pulsating current type and direct current type. In the fire receiver, a district circuit line for connecting a detector is extended to the outside, and one or more detectors are connected to the district circuit line. In a pulsating current type fire receiver, a pulsating current is also applied to the district circuit line, and in a DC type fire receiver, a direct current is applied to the district circuit line. In the DC type, the fire receiver and detector have a communication function, and each sends and receives various information, which is sometimes used as information necessary for fire treatment.
There was a time in the past when the pulsating current type was the mainstream, but recently the direct current type has become mainstream. In the case of the DC type, there are models in which the fire receiver and detector communicate and exchange information with each other, and this exchange of information enables more precise fire alarms, which has become common in recent years. However, pulsating type fire receivers still exist and continue to operate. Therefore, suppliers must also provide sensors compatible with pulsating flow, if necessary for maintenance. Therefore, suppliers have to prepare both pulsating current sensors and direct current sensors, and the number of sensor models has increased.

Japanese Patent Application Publication No. 10-188154

As shown in Patent Document 1, there is a sensor with a communication function that can communicate with a fire receiver. In this case, the fire receiver applies direct current to the district circuit line. When a sensor with a communication function is connected to a pulsating current type fire receiver, the communication function is inhibited by voltage changes in the pulsating current (full-wave waveform or half-wave waveform), resulting in an increase in the current consumption of the sensor and a failure of the sensor to communicate. There were times when it was determined that something was wrong, and normal operation was no longer possible.

Therefore, the present invention has been made in view of these points, and it is possible to prevent the pulsating type fire receiver from being judged as a communication error failure even if a sensor with a communication function is installed in the pulsating type fire receiver. The purpose is to be able to install a detector with communication function in the fire receiver as well.

In order to achieve the above object, the fire detector according to claim 1 of the present invention is a fire detector with a communication function connected to a district circuit line from which a fire receiver extends, wherein the fire detector detects pulsating current. It has a pulsating current detection circuit that detects the pulsating current, and further has a communication circuit that can send and receive information through communication with the fire receiver, and the pulsating current detection circuit detects that pulsating current is applied to the district circuit line. Then, the communication function of the communication circuit is stopped.

According to the fire detector having the above configuration, a pulsating current detection circuit is provided, and when a pulsating current applied to the district circuit line is detected, the communication function can be stopped, so unnecessary operations can be reduced. This has the effect of reducing the power consumption of the fire detector.

The communication circuit of the fire detector according to the second aspect of the invention is characterized in that the communication circuit stops detecting a communication abnormality while the communication function is stopped.

According to the sensor having the above configuration, even if it is connected to a pulsating flow type receiver, it will not detect any communication abnormality, and will have the effect of not outputting unnecessary alarms.

The pulsating current detection circuit of the fire detector according to claim 3 is characterized in that when it is detected that the current is below a predetermined threshold value at a predetermined time interval, it is determined that a pulsating current is being applied to the district circuit line. do.

According to the above configuration, since pulsating current can be detected by a simple method, it is possible to form a pulsating current detection circuit at low cost.

The pulsating current detection circuit of a fire detector according to a fourth aspect of the present invention is characterized in that when a communication abnormality is continuously detected a predetermined number of times, it is determined that pulsating current is being applied to the district circuit line.

According to the above configuration, since pulsating current can be detected by a simple method, it is possible to form a pulsating current detection circuit at low cost.

According to the present invention, it is possible to use a sensor with a communication function in a pulsating flow type receiver, and since the sensor can be shared, the number of types of sensors can be reduced, and the cost of the sensor can be reduced. This reduces the number of types of sensors during equipment design and installation, reducing the effort required to select sensors.
Further, false detection of communication abnormalities and false alarms due to pulsating current can be prevented, and power consumption of the sensor can be reduced.

1 is a diagram showing a configuration example of a fire alarm system S. FIG. It is a figure which shows the pulsating current waveform and DC waveform applied to a district circuit line. FIG. 2 is a block diagram showing the configuration of a pulsating flow type fire receiver and sensor. FIG. 2 is a block diagram showing the configuration of a DC type fire receiver and a sensor with a communication function. FIG. 2 is a block diagram showing the configuration of a pulsating flow type fire receiver and a sensor with a communication function.

FIG. 1 is a diagram showing an example of the configuration of a fire alarm system S. As shown in FIG. The fire alarm system S includes a fire receiver 1 and a plurality of detectors 3. The fire receiver 1 is connected to a plurality of district circuit lines 2, and is connected to a plurality of detectors 3 via the district circuit lines 2. The district circuit line 2 is an external wiring responsible for supplying communication signals and power between the fire receiver 1 and the detector 3. The number of sensors 3 that can be connected to a pair of district circuit lines 2 is determined by the system, and multiple district circuit lines 2 may be used if necessary. FIG. 1 shows a case where a plurality of district circuit lines 2-1, 2-2, and 2-n are used. The sensor 3 detects smoke and heat generated by a fire as environmental information, and generates environmental data.

A district circuit line 2 connecting the fire receiver 1 and the detector 3 serves both as power source and communication for the detector. The fire receiver 1 does not have a smoothing circuit in order to simplify the power supply circuit, and a pulsating current may also be applied to the district circuit line 2. Here, this is called the pulsating flow type. At this time, since the connected sensor 3 requires a smoothing circuit at the input part of the district circuit line 2 to convert pulsating current into direct current, an increase in cost is unavoidable.
The use of pulsating current in the district circuit line 2 makes communication difficult, so it is rarely used in modern systems that require communication. However, there are still many pulsating flow type systems in operation in the world.
[Description of Figure 2(a)]

This diagram schematically represents the pulsating flow waveform of full-wave rectification. From left to right in FIG. 2A, the waveforms are a fire monitoring period, a sensor activation (fire detection), a recovery pulse, and a fire monitoring period (resumption). When fire monitoring is performed using pulsating current, the sensor 3 detects a fire and is activated, so that the impedance inside the sensor decreases and reaches L level. At this time, the L level is approximately 1 to 6 V, depending on the characteristics of the switching element inside the sensor. When the district circuit line 2 becomes L due to activation of the sensor (fire detection), the receiver 1 detects this and issues a fire display or alarm. Note that the sensor self-maintains the L level indicating a fire condition.

After that, when the presence or absence of a fire is confirmed, the fire receiver 1 sends out a recovery pulse (stops power supply to the district circuit line for a predetermined period of time and sets it to 0V) by the operator's recovery operation, causing the detector 3 to self-maintain. is released, and the sensor 3 returns to the monitoring state. When the sensor 3 detects a recovery pulse during self-holding, it releases the self-holding.
[Explanation of FIG. 2(b)]

This is a system in which a fire receiver 1 applies direct current to a district circuit line 2.

It schematically represents the waveform of 24V DC, which is the rated voltage. From left to right in FIG. 2(b), the waveforms are a fire monitoring period, a sensor activation/communication possible period, a recovery pulse, and a fire monitoring period (resumption).

When the sensor is activated, the impedance inside the sensor decreases and becomes L level. At this time, the L level is approximately 1V to 6V depending on the characteristics of the switching element inside the sensor. When the district circuit line 2 becomes L due to the activation of the detector 3 (fire detection), the fire receiver 1 detects this and issues a fire display or alarm. After that, when the presence or absence of a fire is confirmed, the operator performs a recovery operation to send out a recovery pulse (stopping the power supply to the district circuit line and reduce it to 0V for a predetermined period of time) to release the self-holding of the sensor 3 and detect it. The device 3 shifts to the monitoring state again.

Here, the difference from FIG. 2(a) is that in addition to the difference between pulsating current and direct current, communication performed during the communicable period when the sensor is activated is added. (Only when using a sensor with a communication function and a receiver with a communication function) Using this period, the fire receiver 1 sends and receives fire information held by the sensor 3 and individual information of the sensor 3. conduct. This example shows communication using a pulse waveform. If the district circuit line 2 becomes 0V due to the restoration operation of the fire receiver 1 while the detector 3 is self-holding, the detector releases the fire self-holding.

When a sensor with a communication function and a receiver with a communication function are used, the sensor may receive a restoration message through communication, and at this time may release self-holding.
[Explanation of Figure 3]

It is a block diagram of a pulsating flow type fire receiver 1 and a pulsating flow type sensor 3 with full wave rectification. The power supply circuit 12 of the fire receiver 1 is only a full-wave rectifier circuit and does not include a smoothing circuit. Therefore, the voltage waveform generated in the connected district circuit line 2 becomes a pulsating current in which the chevron-shaped waveform shown in FIG. 2(a) is lined up. Further, a pulsating flow type sensor 3 is connected to the district circuit line 2.
[Block diagram of fire receiver (left side of Figure 3)]

The control circuit 13 is a central circuit that sends and receives information from each circuit described later, makes judgments, and issues operational instructions.
The fire signal determination circuit 14 is as follows. When the sensor 3 detects a fire and turns on the switching circuit 26, the impedance of the district circuit line 2 is greatly reduced. A current limiting circuit 11 is provided to protect the district circuit line 2 of the fire receiver 1, the switching element of the detector 3, the power supply circuit 12 of the fire receiver 1, etc. from being damaged due to a large current flowing due to a drop in impedance. ing. Although the current limit value varies depending on the model of the fire receiver 1, it is generally limited to about 50 mA to 100 mA.

The fire signal determination circuit 14 monitors the impedance of the district circuit line 2, and determines that the sensor 3 is transmitting a fire signal when it reaches a predetermined value. Although not shown, a terminator is connected to the final end of the district circuit line 2 to monitor disconnection of the district circuit line 2. The fire signal determination circuit 14 monitors the current passing through the terminator and also determines if the district circuit line 3 is disconnected.

When the fire signal determination circuit 14 determines that there is a fire, the control circuit 13 instructs the alarm circuit 16 and the operation/display circuit 17 to issue an alarm, display, interlock and transfer information (not shown), etc.
The alarm circuit 16 performs an alarm operation corresponding to the fire, such as the main sound or the ringing of the district bell, according to instructions from the control circuit 13.
The operation/display circuit 17 displays the screen of the fire receiver 1 corresponding to the fire according to instructions from the control circuit 13, and also transmits the operation contents of the operation section of the fire receiver 1 to the control circuit 13.
When the operation/display circuit 17 receives a recovery operation from the operation section of the fire receiver 1, the control circuit 13 operates the recovery pulse generation circuit 15, sends out a recovery pulse to the district circuit line 2, and sets the district circuit line 2 to a predetermined position. Set the time to 0V. When the district circuit line 2 is controlled to 0V, the self-holding state of the switching self-holding circuit 26 of the sensor 3 is released.
[Block diagram of sensor (right side of Figure 3)]

In order to obtain electric power from the district circuit line 2, the pulsating current is smoothed by a smoothing circuit 22, and a constant voltage circuit 23 converts it into a necessary voltage inside the sensor and supplies it. In this example, in order to operate the smoothing circuit 22 efficiently and to prevent the influence of the smoothing circuit 22 from being transmitted to the district circuit line, a backflow prevention circuit 21 is provided to separate the smoothing circuit 22 and the district circuit line 2. .

The fire detection circuit 25 detects the presence or absence and amount of fire phenomena such as smoke, heat, and flames, and sends fire information to the control circuit 24 when a predetermined value is exceeded.

When the control circuit 24 detects fire information, it operates the switching circuit 26 to lower the impedance of the district circuit line 2 and maintain it. Due to the impedance drop, the district circuit line 2 becomes L, and is sent to the fire receiver 1 as a fire signal.
[Explanation of Figure 4]

FIG. 4 is a block diagram of the DC type fire receiver 1 and the DC type detector 3 (with communication function). The power supply circuit 12 of the fire receiver 1 is equipped with a DC power supply circuit that can stably supply DC. Therefore, the voltage waveform generated on the connected district circuit line 2 becomes the DC waveform shown in FIG. 2(b). Further, a DC type sensor 3 (with communication function) is connected to the district circuit line 2. This type differs greatly from the pulsating flow type in that the fire receiver 1 and detector 3 have communication circuits.
[Block diagram of receiver (left side of Figure 4)]

Only the points that are significantly different from the pulsating flow type will be explained.
The power supply circuit 12 is a circuit capable of outputting stable direct current, and applies the stable direct current to the district circuit line 2. A communication circuit 18 is also installed to receive signals from the district circuit line 2 so that detailed fire information can be obtained when the detector 3 is sending out a fire signal. The functions of other circuits are similar to the pulsating flow type.
[Block diagram of sensor (right side of Figure 4)]

As with the fire receiver 1, only the points that are significantly different from the pulsating flow type will be explained.
Since direct current is applied to the district circuit line 2, a smoothing circuit is not required in the power supply circuit of the sensor, and therefore only a constant voltage circuit 31 is provided to supply the necessary voltage. Furthermore, it has a communication circuit 35 for communicating with the fire receiver 1 to transmit and receive fire information. The communication circuit 35 starts communication by detecting a communication pulse. Fire information including unique information of the detector 3 is transmitted to the fire receiver 1 through communication. Further, when detecting an abnormality in the communication waveform or failure of the communication procedure, the abnormality information is stored internally as a communication abnormality, and the stored abnormality information is sent to the fire receiver 1 when communication is restarted.

Further, in the case of a sensor having a self-diagnosis function, the self-diagnosis result can be transmitted to the receiver 1 through the communication function. Communication protocols are not mentioned here.
The functions of other circuits are similar to the pulsating flow type.

[Example]
[Description of Figure 5]
FIG. 5 is a block diagram showing an embodiment of the present invention.
[Block diagram of receiver (left side of Figure 5)]
The fire receiver 1 is the same as the pulsating type shown in FIG. What differs here is the internal configuration of the connected sensor.
[Block diagram of sensor (right side of Figure 5)]

In addition to the configuration of the sensor 3 in the case of the DC type shown in FIG. 4, a pulsating current detection circuit 36 is added. As shown in Fig. 2(a), in the case of Japan, in pulsating flow, the point at which 0 V becomes 0 V occurs periodically at approximately every 10 ms for 50 Hz AC input, and approximately every 8.3 ms for 60 Hz AC input. appear. The pulsating current detection circuit 36 constantly monitors the district circuit line 2, and when it detects the above-mentioned law, it determines that there is a pulsating current, and the information is sent to the control circuit 32. When information indicating that the control circuit 32 has detected the pulsating flow is input, the control circuit 32 recognizes that it is connected to the pulsating flow type fire receiver 1. After this, the communication circuit 35 is turned off and the communication circuit 35 shifts to the communication OFF mode. When operating in the communication OFF mode, the area circuit line communication monitoring during normal operation and information communication during a fire are not performed, and unnecessary activation of communication circuits is eliminated, so current consumption is reduced.

In addition, in the case of a sensor with a self-diagnosis function, the self-diagnosis result can be transmitted to the fire receiver 1 through the communication function, but the sensor does not recognize that it is connected to the pulsating current type fire receiver 1. When the system is running, the sending of self-diagnosis results is also stopped.

As described above, as a method of detecting a pulsating flow, a point at which the voltage becomes 0V that appears periodically is detected, but a positive voltage pulsating flow sine wave waveform may also be detected.

Furthermore, if a communication abnormality is detected a predetermined number of times, it may be determined that the communication abnormality is due to pulsating flow, and the pulsating flow may be detected.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes can be made within the scope of the gist. be. For example, all or part of the device can be functionally or physically distributed and integrated into arbitrary units. In addition, new embodiments created by arbitrary combinations of multiple embodiments are also included in the embodiments of the present invention. The effects of the new embodiment resulting from the combination have the effects of the original embodiment.

S Fire alarm system 1 Fire receiver 2, 2-1, 2-2, 2-n District circuit line 3 Detector (smoke or heat)
11 Current limiting circuit 12 Power supply circuit 13 Control circuit 14 Fire signal judgment circuit 15 Recovery pulse generation circuit 16 Alarm circuit 17 Operation/display circuit 18 Communication circuit 21 Backflow prevention circuit 22 Smoothing circuit 23 Constant voltage circuit 24 Control circuit 25 Fire detection circuit 26 Switching self-holding circuit 31 Constant voltage circuit 32 Control circuit 33 Fire detection circuit 34 Switching self-holding circuit 35 Communication circuit 36 Pulsating current detection circuit L Low level

Claims (4)

In a fire detector with a communication function connected to the district circuit line from which the fire receiver extends,
The fire detector has a pulsating current detection circuit that detects pulsating current, and further has a communication circuit that can exchange information with the fire receiver through communication, and the pulsating current detection circuit detects pulsating current on the district circuit line. A fire detector characterized in that the communication function of the communication circuit is stopped when detecting that a current is applied. 2. The fire detector according to claim 1, wherein the communication circuit of the fire detector stops detecting a communication abnormality while the communication function is stopped. The pulsating current detection circuit of the fire detector determines that pulsating current is being applied to the district circuit line when detecting that the current is below a predetermined threshold at a predetermined time interval. 1 or 2 fire detectors. 3. The fire detection device according to claim 1, wherein the pulsating current detection circuit of the fire detector determines that pulsating current is being applied to the district circuit line when a communication abnormality is continuously detected a predetermined number of times. vessel.

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