JP2003315307A - Safety sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a safety sensor capable of detecting fire quickly and reliably at an early stage. <P>SOLUTION: A CO sensor 40 is connected to a fire sensor 36 via a communication means 110 and is driven in a pulse-like manner. A pulse signal control means 22 is provided for changing the pulse interval of the CO sensor 40 in response to a signal transmitted from the fire sensor 36 via the communication means 110. Changing the pulse interval of the CO sensor 40 in response to the signal from the fire sensor 36 serves to prolong the life of a battery when it is used as a power source for driving, and to reliably detect a fire abnormality at an early stage by changing the timing of detection of the CO sensor 40 in abnormal situations. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety sensor for detecting carbon monoxide or fire generated by incomplete combustion of indoor combustion equipment.

[0002]

2. Description of the Related Art Conventional gas sensors of various types and shapes such as a semiconductor type, a hot wire semiconductor type, and a solid electrolyte type have been proposed. As an example, the solid electrolyte type has a pair of platinum electrodes 2 and 3 on both surfaces of a plate-shaped solid electrolyte 1 as shown in FIG.
And cover both sides with plate-shaped gas selective permeators 4 and 5,
A heater 6 is formed on the surface of one of the gas selective permeators 4 and an oxidation catalyst layer 7 is placed on the heater 6.

[0003]

Generally, gas sensors are selectively sensitive to carbon monoxide, methane, propane, hydrogen, etc., and are used for gas leak alarms, CO alarms and the like. Therefore, the final safety device is required to have high sensitivity, fast response, high reliability, high selectivity, and low power consumption.

However, in the conventional gas sensor shown in FIG. 10, the solid electrolyte 1, the gas selective permeation body 4, and the oxidation catalyst layer 7 have large heat capacities of the plate-shaped chips, so that a large amount of electric power is required to keep the sensor at the operating temperature. Therefore, a commercial power supply was necessary for that. Therefore, the power outlet is always occupied, and it is usually installed in a very limited place such as a kitchen in a general household. However, considering the current situation where unfortunate accidents due to poor combustion of indoor combustors such as heaters and water heaters are still present, and the spread of central heating due to high airtightness and insulation of houses, CO alarms need to be spread. There is. However, it is very inconvenient to occupy a power outlet in a home where electric appliances are overflowing, and it is desired to improve the installability.

In order to solve such a problem, a thin film gas sensor having the configuration shown in FIG. 11 has been proposed (Japanese Patent Laid-Open No. 2001).
-194329). This thin film gas sensor has a substrate 8
A solid electrolyte thin film 11 having oxygen ion conductivity formed on the upper surface of the heater 9 formed above via an electric insulating layer 10, a pair of electrode 12 thin films formed on the solid electrolyte thin film 11, and the pair of The electrode 12 has one electrode 12 ′ and the oxidation catalyst layer 13 is provided on the other electrode 12 ′.
It has been shown that with this configuration, the heat capacity can be reduced to enable pulse driving, and as a result, significant power saving can be achieved and battery driving can be performed. However, since the semiconductor type, the hot wire semiconductor type, the solid electrolyte type, etc. are all heated by a heater to a predetermined temperature, it is necessary to set a large pulse interval in order to maintain the battery capacity for a long time.

However, when the pulse interval is large, CO detection may be delayed if CO is rapidly generated in an emergency such as a fire. In order to solve this, FIG.
A driving method of a heater as shown in No. 2 is disclosed (Japanese Patent Laid-Open No. 2001-194329). This is because the heating means operates intermittently and the pulse interval (th2) when the output of the CO sensor is higher than the first set value (h2).
Is lower than the first set value (h1), the pulse interval (th
By making it shorter than 1), CO can be detected earlier in an emergency. However, even with this method, CO
When the output of the sensor is lower than the first set value, the pulse interval is lengthened to operate, so that CO detection may be delayed in the initial stage of CO generation. In addition, there are two types of fire sensor: one is temperature detection and the other is smoke detection.
In some cases, cigarette smoke or steam generated an alarm.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a safety sensor capable of early and surely detecting in the initial stage of a fire.

[0008]

In order to solve the above-mentioned problems, the safety sensor of the present invention pulse-drives a CO sensor connected to a fire sensor by communication means, and the fire sensor is connected via the communication means. It has pulse signal control means for changing the pulse interval of the CO sensor according to a signal from the sensor. By changing the pulse interval of the CO sensor by the signal transmitted from the fire sensor via the communication means, the battery life when driven by a battery power source is extended and the timing of detection of the CO sensor is changed at the time of abnormality. By doing so, a fire abnormality can be detected and warned early and reliably.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 drives a CO sensor connected to a fire sensor by a pulse by a communication means, and the CO sensor is transmitted by a signal from the fire sensor via the communication means. Since the pulse signal control means for changing the pulse interval is provided, the pulse interval can be changed as necessary to change the detection timing.

According to the second aspect of the invention, when the fire sensor detects an abnormality that causes a fire, a control signal for shortening the pulse interval of the CO sensor is issued, so that the room temperature rises or smoke is emitted. When it occurs, the pulse interval of the CO sensor can be shortened, the detection timing can be advanced, and danger can be detected early.

According to a third aspect of the present invention, when the fire sensor detects an abnormality that causes a fire, the control signal for shortening the pulse interval of the CO sensor emitted from the communication means connected to the fire sensor is: Since the output level of the fire sensor is set to a level lower than the output level for issuing a warning for informing of a fire danger, the pulse of the CO sensor is generated at the initial stage when the room temperature rises or smoke is generated. It is possible to detect the fire early and surely by shortening the interval to accelerate the detection timing and detecting the temperature or smoke and CO.

According to the invention of claim 4, an alarm is issued when the output of the fire sensor is equal to or higher than a predetermined value and the rate of increase of the output of the CO sensor is equal to or higher than the predetermined value. When CO suddenly increases due to the occurrence of
Even if the CO concentration does not reach the preset alarm concentration, an alarm can be issued to notify the danger early.

According to a fifth aspect of the present invention, when the fire sensor no longer detects an abnormality that causes a fire, a control signal for increasing the pulse interval of the CO sensor or for setting the pulse interval to a predetermined value is transmitted from the communication means. When the output of the CO sensor is less than or equal to a predetermined value, the pulse interval of the CO sensor is lengthened, or the pulse interval is set to a predetermined value. Therefore, when the fire sensor no longer detects an abnormality that causes a fire, The CO sensor can be returned to the normal pulse interval to save power, and in particular, when a battery is used as the power source, the battery life can be extended.

According to a sixth aspect of the present invention, a CO sensor is provided with a substrate having a high heat resistance and low thermal conductivity, a heater formed on the substrate, an insulating film provided so as to cover the heater, and an insulating film provided on the insulating film. The oxygen ion conductive solid electrolyte membrane is provided, and the catalyst is formed on one of the pair of platinum electrodes formed on the solid electrolyte membrane. Since it is formed of a thin film on a heat-resistant and low-thermal-conductivity substrate, the heat capacity is made small and the solid electrolyte is instantly heated to a predetermined temperature, so that it is possible to drive the CO sensor in a pulsed manner. It is possible to drive the CO sensor with a power supply.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram of a safety sensor in Embodiment 1 of the present invention. In FIG. 1, 19 is a safety sensor and 40 is a CO sensor. CO sensor 40
Is configured to intermittently heat the CO detection unit 20 with the heater 21. Reference numeral 22 is a pulse signal control means, and the pulse output voltage output from the microcomputer 23 as the signal control means is input to the + terminal of the operational amplifier 24, and the operational amplifier is passed from the output terminal through the filter including the fixed resistor 25 and the capacitor 26. It becomes the input of the 27+ terminal. PNP transistor 28, NPN transistor 29, and DC power supply 3
Reference numeral 0 constitutes a power supply means 31 to the heater 21.
In this configuration, current flows from the DC power supply 30 through the emitter-collector of the PNP transistor 28 and into the heater 21. The magnitude of the current depends on the base current of the PNP transistor 28. The base current of the PNP transistor 28 is controlled by the base voltage of the NPN transistor 29, that is, the output voltage of the operational amplifier 27. Since the operational amplifier 27 operates so that the − terminal and the + terminal have the same potential, the current flowing into the heater 21 is determined, the variation of the resistance value due to heat generation reaches an equilibrium state, and the voltage applied to the heater 21 is determined. The temperature balance of the heater 21 is also achieved,
The CO detection unit 20 is heated.

When the temperature rises, the resistance value of the heater 21 increases and the voltage at the negative terminal of the operational amplifier 27 increases. When the voltage difference from the + terminal becomes small, the base current of the NPN transistor 29 is narrowed. Therefore, the PNP transistor 29
Is also throttled, the current flowing into the heater 21 is also throttled, the equilibrium state is reached, and a voltage corresponding to the pulse output voltage is applied to the heater 21. And heater 2
The temperature of 1 is controlled to a constant value. The CO detection unit 20 heated to a constant temperature outputs a voltage according to the concentration of carbon monoxide gas, and the output signal is input to the signal processing unit 32. Inside the microcomputer 23, the CO concentration is determined based on the signal from the signal processing unit 32, and a notification signal is output to the notification unit 33 as needed. A signal from a fire sensor 36 is input to the microcomputer 23 via an internal bus 34 and a communication adapter 35 which is a communication means.

FIG. 2 is a signal transition diagram showing a signal transmission state from the fire sensor 36 to the microcomputer 23. Fire sensor 3
When the transmission signal A (201) is transmitted from 6 to the communication adapter 35 via the internal bus 34, the communication adapter 35 receives this and returns the response signal A (202). If the communication adapter 35 cannot receive the transmission signal A (201), it does not return the response signal A (202). The fire sensor 36 receives this response signal A (202), and the communication between the fire sensor 36 and the communication adapter 35 is completed.

Next, the communication adapter 35 transmits to the microcomputer 23 a transmission signal A '(203) obtained by converting the received transmission signal A into a communication form with the microcomputer 23. Microcomputer 2
3 receives this and returns a response signal A ′ (204). If the microcomputer 23 cannot receive the transmission signal A '(203), it does not return the response signal A' (204). The communication adapter 35 receives the response signal A '(204), and the communication between the communication adapter 35 and the microcomputer 23 is completed. By the above, the fire sensor 36 transmits to the microcomputer 23.

FIG. 4 is a flow chart showing the operation of the communication adapter 35 having the above configuration, and FIG. 5 is a fire sensor 36.
3 is a schematic diagram of a communication path between the microcomputer and the microcomputer 23. FIG. The operation of the communication adapter 35 will be described with reference to FIGS. 4 and 5. This is a case where the communication means 110 receives via the internal bus 34 and transmits to the device connection means 114. As shown in FIG. 4, the determination unit 111 determines whether the content received by the communication unit 110 needs to be communicated to the microcomputer 23 (S101).
The determination method is to determine whether or not the destination of the received content is the microcomputer 23, whether the received content is related to the microcomputer 23, the received content and the past content stored in the storage unit 112, and change. It is determined whether or not there is, and communication is performed when the destination of the received content is the microcomputer 23, the received content is related to the microcomputer 23, and there is a change from the past content stored in the storage unit 112. It is judged necessary. That is, it is determined whether the predetermined CO level is exceeded or the detection pulse interval should be shortened.

Next, the communication control means 115 selects and sets the communication partner / communication content. The communication partner is the microcomputer 23
Is an identification code for communication designating (S102).
The communication content is a content newly required for extracting a necessary part from the content received by the communication means 110 from the internal bus 36 or for communication between the communication adapter 35 and the microcomputer 23. It may also include code conversion for communication and encryption for security.

After selecting and setting the communication partner / content, the device connecting means 114 sends the information to the microcomputer 23 (S103). When the communication adapter 35 and the microcomputer 23 are transmitting and receiving at the communication timing, the transmission is performed at the communication timing. After the transmission, if the response signal is to be returned from the microcomputer 3, the response signal is waited for a fixed time (S104). Whether the response signal is to be returned from the microcomputer 23 is transmitted from, for example, the communication adapter 35 (S103).
There are various methods such as the specification of whether or not to respond to the communication content is included, or the response signal is previously agreed between the communication adapter 35 and the microcomputer 23.

When the response signal is to be returned from the microcomputer 23, the device connection means 114 receives the response signal (S105), and if the content is normal (S10).
6) The communication is finished. If the response signal cannot be received, or if the content is abnormal even if it is received, retransmit the transmitted content.If communication is still not possible, notify or display the communication abnormality to the user or display it externally. Notify (S107).

The communication is not limited to the above-mentioned embodiment, and any communication can be used as long as it can communicate between the fire sensor 36 and the microcomputer 23 via the communication adapter 35.

With this configuration, when the fire sensor 36 detects an abnormality of a fire factor, the microcomputer 2 of the CO sensor 40
By sending a signal to No. 3, it is possible to detect the expected spread of carbon monoxide (due to a fire or the like) early by shortening the detection cycle of neighboring sensors.

FIG. 5 is a block diagram of a CO sensor that constitutes a safety sensor according to the first embodiment of the present invention. In FIG. 5, 40 is a CO sensor. As the CO sensor 40, there are various types such as a semiconductor type, a hot wire semiconductor type, a solid electrolyte type, and a potentiostatic electrolysis type. In the present embodiment, the solid electrolyte type is used. 41 is a heat resistant and low thermal conductive substrate,
Here, quartz glass of about 2 mm × 2 mm × 0.3 mm is used. A platinum heater 42 has a resistance value set to a predetermined temperature by a sputtering method, an electron beam evaporation method or the like. An insulating film 43 is formed by covering a thin film of an insulating material such as alumina, silica, or silicon nitride by a sputtering method, an electron beam evaporation method, or the like. 44
Is a solid electrolyte film formed on the insulating film 43 in an area smaller than that of the insulating film 43, and a solid electrolyte having oxygen ion conductivity (8% yttria-stabilized zirconia) is about 0.4 mm × 0.6 mm by a sputtering method. It is formed to the size of. As the solid electrolyte, all solid electrolytes having oxygen ion conductivity can be used, but yttria-stabilized zirconia (YSZ) obtained by mixing a small amount of yttria with zirconia and firing is relatively inexpensive and easily available. Reference numerals 45a and 45b are electrodes, and platinum is formed on the sensitive film by a sputtering method. Platinum may be partially mixed with a noble metal such as palladium, ruthenium or rhodium. In addition, all electrode materials generally used for the solid electrolyte type can be used. Reference numeral 46 denotes a catalyst set on one electrode 45a. The catalyst 46 may be any catalyst that oxidizes and decomposes the gas to be measured. However, noble metals such as platinum, palladium, ruthenium and rhodium, oxides such as vanadium and manganese, or A mixture of these materials supported on alumina or the like is formed by a screen printing method. In this embodiment, the electrodes 45a and 4 are
Although platinum is used for 5b and the catalyst 46 is set on one of the electrodes 45a, the catalyst 46 is not used, but the electrode is made of different perovskite-type composite oxides or is composed of perovskite-type composite oxides and gold. You may. In the above structure, electric power is supplied to the power source (not shown) heater 42 to heat the solid electrolyte membrane 44 to a predetermined temperature (400 ° C. to 500 ° C.). When the solid electrolyte membrane 44 reaches a predetermined temperature, the electrode 45
Electrons are exchanged at the interfaces between a and 45b, the solid electrolyte membrane 44, and air, and oxygen ions are generated. Here, if CO is present in the air, at the electrode 45a on which the catalyst 46 is mounted, C
O is oxidized by the oxidation catalyst 46 and C reaches the electrode 45a.
O never reaches. At the other electrode 45b, CO is oxidized to CO2 on the surface of the electrode 45b. Oxygen ions in the solid electrolyte membrane 44 are used for this oxidation reaction, and as a result, a difference occurs in the electrode reaction between the two electrodes, the equilibrium of the solid electrolyte oxygen ions is disrupted, and a potential difference occurs between the two electrodes. The CO concentration can be detected by detecting this potential difference.
The quartz glass used for the substrate 41 has a thermal conductivity of 1.5 W.
/ MK is smaller than the insulating film 43 (35 to 45 W / mK) and the solid electrolyte film 44 (6 W / mK). Therefore, when heated by the heater 42, the temperature of the substrate 41 hardly rises. Directly above solid electrolyte membrane 44
Since it is possible to raise the temperature only in the region and its vicinity, it is possible to significantly reduce the power consumption for heating. Further, since the thermal shock strength is high, it is possible to raise the temperature to a predetermined temperature in a short time. 1 in the above configuration
It was possible to raise the temperature to 450 ° C. with the electric power of 5 mWsec. Oxygen ion conductivity occurs in the solid electrolyte membrane 44 at a predetermined temperature. That is, CO can be detected when the solid electrolyte reaches a predetermined temperature. In this embodiment, since quartz glass having a small thermal conductivity is used for the substrate 41 and the solid electrolyte is also formed of a thin film, it is possible to instantly raise the temperature of the solid electrolyte membrane 44 to a predetermined temperature. Since it can be driven in a pulsed manner and power consumption can be greatly reduced, it can be driven by a battery power source. In the configuration of this embodiment, 10 msec
It was possible to raise the temperature to 450 ° C. by energizing the heater 42, and the temperature was returned to room temperature about 0.5 sec after the energization of the heater 42 was stopped. Therefore, the pulse interval is 0.5 sec
The pulse interval can be arbitrarily set up to about 30 seconds, which is not a problem for normal measurement. In addition, the pulse interval 0.
Even if the CO sensor is downsized for 5 sec, 0.5 se
It is also possible to set it to c or less.

In this embodiment, it is premised that the CO sensor is driven in a pulsed manner, but it is also possible to drive it in a pulsed manner by a semiconductor type or a hot wire semiconductor type. However, these methods are greatly affected by moisture adsorbed on the semiconductor surface, and when the pulse interval is large, the output decreases due to the effect of adsorbed water, which requires long-time overheating to remove moisture. It is difficult to set the pulse interval arbitrarily.

This embodiment takes advantage of the fact that the pulse interval of the solid electrolyte type can be arbitrarily set, and in combination with the fire sensor 36, in an emergency such as a fire, an abnormality can be reliably detected at an early stage to prevent escape delay. It provides a safety sensor that can avoid unfortunate situations as much as possible, and the operation thereof will be described below. The operation pattern of the safety sensor can be largely classified into the following three cases.

1. When only the output of the fire sensor 36 changes 2. When only the output of the CO sensor 40 changes 3. When the outputs of both the fire sensor 36 and the CO sensor 40 change.

The operation when only the output of the fire sensor 36 changes is shown in FIG. The fire sensor 36 may be a method that measures room temperature with a thermistor or a method that measures smoke density with a phototransistor, but since power consumption is low in both cases, it is always energized and continuously monitored even when battery power is used. It is possible. Fire sensor 3 under normal conditions
The detection output of 6 is k0, and the pulse interval of the CO sensor 40 is t
a. ta is normally about 30 seconds that does not hinder the detection of CO (for example, detection of only one time may cause a false alarm, so if CO detection is detected by two detections, it is detected within 1 minute of CO generation. It is set to about the time that can be done. When the detection output becomes k1 for some reason, it is determined to be abnormal, and the CO sensor 40 is detected by the pulse signal control means 22.
The pulse interval of is changed to tb. The fire sensor 36 is CO
Continuous monitoring is continued regardless of the detection output of the sensor 40.
When the detection output becomes k2, it is judged as a fire and an alarm is issued.

The operation when only the output of the CO sensor 40 changes is shown in FIG. The CO sensor 40 normally operates at the pulse interval ta, but even when the detection output of the fire sensor 36 does not change, when the CO detection output becomes c1, the pulse signal control means 22 changes the pulse interval of the CO sensor 40. Change to tb. tb is 0.5 as described above.
It can be set to about sec, and detection substantially equivalent to continuous detection is possible. The CO detection output continues to increase, and when the detection output reaches c2, it is determined that CO is abnormal,
Give an alarm.

Next, FIG. 8 shows the operation when the outputs of both the fire sensor 36 and the CO sensor 40 change. In a normal state, the detection output of the fire sensor 36 is k0, and the pulse interval of the CO sensor 40 is ta. When the detection output of the fire sensor 36 becomes k1 for some reason, it is determined that an abnormality causing a fire has occurred, and the pulse signal control means 2
2, the pulse interval of the CO sensor 40 is changed to tb. The fire sensor 36 continues continuous monitoring regardless of the detection output of the CO sensor 40, and when the detection output becomes k2, it determines that there is a fire and issues an alarm. On the other hand, the CO sensor 40 continues to detect at the pulse interval tb, and the CO concentration is c3 (CO
When the concentration reaches a concentration lower than the concentration c2 at which an alarm is issued when the output of only the sensor 40 changes), it is determined that the risk of fire is high and an alarm is issued.

As described above, by combining the fire sensor 36 and the CO sensor 40, it is possible to reliably notify the danger earlier than in the case of detecting each independently.

Further, as shown in FIG. 9, the fire sensor 36 once detects an abnormality that causes a fire, the output of the fire sensor 36 becomes k1 or more, and the pulse interval of the CO sensor 40 becomes t.
After it becomes 2, it no longer detects abnormalities that cause fire,
When the output of the fire sensor 36 becomes k1 or less, the output of the CO sensor 40 is set to the predetermined value c by the communication adapter 35.
When it becomes 2 or less, the pulse interval of the CO sensor 40 is returned to ta by the pulse signal control means 22 to return to the normal detection state. Therefore, even if a battery is used as a power source, it can be used for a long time without consuming unnecessary power.

Although the fire sensor 36 and the communication adapter 35 communicate with each other via the internal bus 34 in the above description, the communication with the fire sensor is not limited to this, and the fire sensor is communicated via a communication line such as the Internet, wireless communication, or wired communication. Anything that communicates with the adapter may be used. In particular, wireless communication using radio waves is effective when the fire sensor and the CO sensor are installed separately. For example, a fire sensor is installed near the ceiling in a living room or the like, while a CO sensor is installed near a gas stove in a kitchen or the like. If this is connected by wireless communication, the installation work is easier and the appearance is better than wired.

A communication adapter may be provided on the CO sensor side, a communication adapter may be provided on the fire sensor side, or both may be provided.

[0037]

As described above, according to the present invention, a CO sensor that is driven in a pulsed manner and a fire sensor are combined, and when an abnormality that causes a fire is detected by the fire sensor, the CO sensor is sent via communication means. By shortening the pulse interval of CO and the CO detection interval, the temperature and smoke that cause a fire can be detected at the same time, and the CO can be detected at the same time to reliably and early detect and notify the heat of a fire. Not only the danger of smoke and smoke but also CO
At the same time, the risk of death can be reduced, and the risk of death due to poisoning due to delayed escape can be reduced. By setting the pulse interval arbitrarily, long-term use is possible even when the battery is used as the power source.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a safety sensor according to an embodiment of the present invention.

FIG. 2 is a signal transition diagram showing a signal transmission state in the safety sensor according to the embodiment of the present invention.

FIG. 3 is a flowchart of the operation of the communication adapter of the safety sensor according to the embodiment of the present invention.

FIG. 4 is a schematic diagram of a communication path between a fire sensor of a safety sensor and a microcomputer according to an embodiment of the present invention.

FIG. 5 is an assembled perspective view of a CO sensor that constitutes a safety sensor according to an embodiment of the present invention.

FIG. 6 is an operation diagram of a safety sensor according to an embodiment of the present invention.

FIG. 7 is another operation diagram of the safety sensor according to the embodiment of the present invention.

FIG. 8 is another operation diagram of the safety sensor according to the embodiment of the present invention.

FIG. 9 is another operation diagram of the safety sensor according to the embodiment of the present invention.

FIG. 10 is a perspective view of a main part of a conventional gas sensor.

FIG. 11 is a perspective view of a main part of another conventional gas sensor.

FIG. 12 is an operation diagram of a conventional gas sensor.

[Explanation of symbols]

22 Pulse signal control means 34 Communication adapter (communication means) 37 Fire sensor 40 CO sensor 41 substrate 42 heater 43 Insulation film 44 Solid electrolyte membrane 45a, 45b electrodes 46 catalyst

Continued front page    (72) Inventor Takashi Niwa             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Kunihiro Tsuruta             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Takahiro Umeda             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Kazunari Nishii             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Yasuo Yoshimura             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 2G004 BB04 BC02 BE27 BF07 BF08                       BJ02 BJ03 BL08 BL19 BM04                       BM09                 5C085 AA06 AB01 AB09 BA17 CA17                       CA30 DA16

Claims (6)

[Claims] 1. A pulse signal control means for driving a CO sensor connected to a fire sensor by a pulse by a communication means, and changing a pulse interval of the CO sensor according to a signal from the fire sensor via the communication means. Having a safety sensor. 2. The safety sensor according to claim 1, wherein when the fire sensor detects an abnormality that causes a fire, a control signal for shortening the pulse interval of the CO sensor is issued by the communication means connected to the fire sensor. 3. The control signal for shortening the pulse interval of the CO sensor, which is emitted from the communication means connected to the fire sensor when the fire sensor detects an abnormality that causes the fire, is output by the output level of the fire sensor. The safety sensor according to claim 1, wherein the safety sensor is issued at an output level lower than an output level for issuing an alarm for informing of a fire danger. 4. The output of the fire sensor is a predetermined value or more,
The safety sensor according to any one of claims 1 to 3, which issues an alarm when the increase rate of the output of the CO sensor is equal to or more than a predetermined value. 5. When the fire sensor no longer detects an abnormality that causes a fire, the communication means outputs a control signal for lengthening the pulse interval of the CO sensor or for setting the pulse interval to a predetermined value, and the output of the CO sensor is changed. The safety sensor according to any one of claims 1 to 4, wherein the pulse interval of the CO sensor is lengthened when it is less than or equal to a predetermined value or the pulse interval is set to a predetermined value. 6. The CO sensor comprises a substrate having heat resistance and low thermal conductivity,
A heater formed on the substrate, an insulating film provided so as to cover the heater, an oxygen ion conductive solid electrolyte film provided on the insulating film, and formed on the solid electrolyte film. The safety sensor according to claim 1, further comprising a catalyst formed on one of the pair of platinum electrodes.