JP2015153058A - Sensor, sensing method, sensing system, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress generation of a false report by discriminating smoke and steam, without learning a threshold.SOLUTION: A sensor 10 comprises: a first sensor 111; a second sensor 112; a processing part 12; and a notification part 13. The first sensor 111 measures smoke density in air, and the second sensor 112 measures density of carbon monoxide in the air. The processing part 12 determines whether a predetermined condition is established about the smoke density measured by the first sensor 111 and the density of carbon monoxide measured by the second sensor 112, or not. The notification part 13 outputs a notification signal when the condition is established. The processing part 12 selects one of a first condition determining one of the smoke density and density of carbon monoxide and a second condition determining both of the smoke density and density of carbon monoxide, as a condition for determination, based on a determination result of a changeover condition determined as smoke density Cs.

Description

  The present invention relates to a sensor for detecting a component of interest in the air, a sensing method used by the sensor, a sensing system using the sensor, and a program used for the sensor.

  Conventionally, a sensor that senses components in the air such as carbon monoxide, smoke, and dust has been provided. For example, Patent Document 1 describes a fire detector that outputs a fire warning signal indicating the possibility of a fire by monitoring the smoke concentration. Patent Document 1 describes a technique for determining a fire using not only smoke but also a temperature difference.

  Patent Document 2 describes a technique for monitoring the concentrations of smoke and carbon monoxide and determining that a fire has occurred when the rate of change of smoke or the rate of change of carbon monoxide exceeds a threshold value. ing.

Japanese Patent No. 4066761 JP 2006-277138 A

  In patent document 1, in order to improve the reliability of fire detection, a threshold value for smoke and a temperature difference is learned. Therefore, it takes a relatively long time before the operation can be actually started.

  On the other hand, in Patent Document 2, a fire alarm is given when the smoke or carbon monoxide concentration exceeds a threshold value, or when the change rate of carbon monoxide exceeds the threshold value. In other words, a fire may be determined only when the smoke concentration exceeds a threshold value. Therefore, there is a possibility that false alarms may occur for steam.

  An object of the present invention is to provide a sensor capable of preventing the occurrence of false alarms without performing threshold learning. Furthermore, an object of the present invention is to provide a sensing method used in the sensor, a sensing system using the sensor, and a program used in the sensor.

  The sensor according to the present invention includes a first sensor for measuring the concentration of smoke in the air, a second sensor for measuring the concentration of carbon monoxide in the air, and the smoke measured by the first sensor. A processing unit that determines whether or not a predetermined condition is satisfied with respect to the concentration of carbon monoxide and the concentration of the carbon monoxide measured by the second sensor, and a notification unit that outputs a notification signal when the condition is satisfied The processing unit includes a first condition defined for only one of the smoke concentration and the carbon monoxide concentration, and a first condition defined for both the smoke concentration and the carbon monoxide concentration. One of the two conditions is selected as the condition based on the determination result of the switching condition defined for the smoke concentration.

  In this sensor, the processing unit considers the concentration of carbon monoxide and a pre-determination unit that determines the difference between the smoke concentration difference with respect to a predetermined reference time and a first determination value as the switching condition. Without the first determination unit determining whether or not the first condition including that the smoke concentration is equal to or higher than a second determination value is satisfied, and the difference regarding the carbon monoxide is a third A second determination unit that determines whether or not the second condition including that the smoke concentration is equal to or higher than a second determination value is satisfied, The pre-determination unit selects the first determination unit when it is determined that the difference regarding the smoke is less than the first determination value, and the difference regarding the smoke is equal to or greater than the first determination value. It is preferable to select the second determination unit when it is determined.

  In this sensor, the pre-determination unit determines whether or not the switching condition is satisfied when a state where the difference regarding the smoke is equal to or more than the first determination value continues for a first determination time. The process shifts to a state in which the second determination unit is selected, and in addition to the difference regarding the carbon monoxide being not less than the third determination value, the smoke concentration is not less than the second determination value. It is preferable to determine whether a condition including the above is satisfied.

  In this sensor, when the state where the smoke concentration is less than a predetermined threshold continues for a second determination time, the front determination unit determines the first determination based on the determination result of the switching condition. It is preferable to return to the state in which one of the second determination unit and the second determination unit is selected.

  In this sensor, it is preferable that the second determination time is set to be longer than the first determination time.

  The sensing method according to the present invention acquires the smoke concentration and the carbon monoxide concentration in the air from the sensor unit, and whether or not a predetermined condition is satisfied with respect to the acquired smoke concentration and carbon monoxide concentration. Is a method for outputting a notification signal from the notification unit when the condition is satisfied, the first condition defined for only one of the smoke concentration and the carbon monoxide concentration; One of the second conditions defined for both the smoke concentration and the carbon monoxide concentration is selected by the processing unit as the condition based on a determination result of a switching condition defined for the smoke concentration. It is characterized by doing.

  In this sensing method, the switching condition is a magnitude of a difference in the smoke concentration with respect to a predetermined reference time and a first determination value, and the first condition does not consider the concentration of carbon monoxide. In addition, the second condition is that the difference with respect to the carbon monoxide is not less than a third determination value, and that the smoke concentration is not less than a second determination value. Is greater than or equal to a second determination value, and when the difference regarding the smoke is less than the first determination value, the processing unit selects the first condition, and the difference regarding the smoke is the first difference It is preferable that the processing unit selects the second condition when the determination value is equal to or greater than the determination value.

  The sensing system according to the present invention includes any one of the above-described sensors and a notification device that performs notification using the notification signal output from the notification unit.

  The program according to the present invention is for causing a computer to function as the processing unit and the notification unit in any of the above-described sensors.

  In the present invention, one of the first condition defined for only one of the smoke concentration and the carbon monoxide concentration, and the second condition defined for both the smoke concentration and the carbon monoxide concentration, The determination condition is selected based on the determination result of the switching condition defined for the smoke density. For this reason, the sensor of the present invention makes it possible to use the concentration of carbon monoxide together when it is difficult to determine only by the concentration of smoke. As a result, the false alarm is generated without learning the threshold value. Can be suppressed.

It is a block diagram which shows embodiment. It is operation | movement explanatory drawing of embodiment. It is explanatory drawing which represented the reading process of embodiment with the flowchart. It is explanatory drawing which represented the alerting | reporting process of embodiment with the flowchart. It is operation | movement explanatory drawing of embodiment. It is explanatory drawing which represented a part of fire determination process of embodiment with the flowchart. It is explanatory drawing which represented the other part of the fire determination process of embodiment with the flowchart. It is explanatory drawing which represented another part of the fire determination process of embodiment with the flowchart. It is operation | movement explanatory drawing of embodiment. It is operation | movement explanatory drawing of embodiment. It is a figure explaining the application example of embodiment. It is a figure explaining the other application example of embodiment.

  As shown in FIG. 1, the sensor 10 described below includes a first sensor 111, a second sensor 112, a processing unit 12, and a notification unit 13. The first sensor 111 measures the smoke concentration Cs in the air, and the second sensor 112 measures the carbon monoxide concentration Cc in the air. The processing unit 12 determines whether or not a predetermined condition is satisfied with respect to the smoke concentration Cs measured by the first sensor 111 and the carbon monoxide concentration Cc measured by the second sensor 112. The notification unit 13 outputs a notification signal when the condition is satisfied. The processing unit 12 selects one of the first condition and the second condition as the condition based on the determination result of the switching condition determined with respect to the smoke density Cs. The first condition is defined for only one of the smoke concentration Cs and the carbon monoxide concentration Cc, and the second condition is defined for both the smoke concentration Cs and the carbon monoxide concentration Cc.

  The processing unit 12 preferably includes a pre-determination unit 1200, a first determination unit 1201, and a second determination unit 1202. The pre-determination unit 1200 determines the magnitude of the difference between the smoke density Cs with respect to a predetermined reference time and the first determination value Vs2 as a switching condition. The first determination unit 1201 determines whether or not the first condition including that the smoke concentration Cs is equal to or higher than the second determination value Vs1 is satisfied without considering the carbon monoxide concentration Cc. . The second determination unit 1202 includes, in addition to the difference ΔCc related to carbon monoxide being equal to or greater than the third determination value Vc2, the second condition including that the smoke concentration Cs is equal to or greater than the second determination value Vs1. Whether or not is satisfied is determined. Then, the front determination unit 1200 selects the first determination unit 1201 when it is determined that the smoke-related difference ΔCs is less than the first determination value Vs2, and the smoke-related difference ΔCs is equal to or greater than the first determination value Vs2. When it is determined that the second determination unit 1202 is selected, the second determination unit 1202 is selected.

  Further, when the state where the smoke difference ΔCs is equal to or greater than the first determination value Vs2 continues for the first determination time Td1, the front determination unit 1200 determines whether the second switching condition is satisfied or not. It is desirable to shift to a state in which the determination unit 1202 is selected. In this case, the pre-determination unit 1200 has a condition that the smoke concentration Cs is equal to or higher than the second determination value Vs1 in addition to the difference ΔCc related to carbon monoxide being equal to or higher than the third determination value Vc2. The second determination unit 1202 determines whether or not it is established. Furthermore, when the smoke concentration Cs is lower than the predetermined threshold value Vs0 continues for the second determination time Td2, the pre-determination unit 1200 and the first determination unit 1201 are based on the determination result of the switching condition. It is desirable to return to a state in which one of the second determination unit 1202 is selected. In this case, it is more desirable that the second determination time Td2 is set to be longer than the first determination time Td1.

  In the sensing method described below, the smoke concentration Cs and the carbon monoxide concentration Cc in the air are acquired from the sensor unit 11, and predetermined conditions are established for the acquired smoke concentration Cs and carbon monoxide concentration Cc. Whether or not the processing unit 12 determines. Further, in this sensing method, a notification signal is output from the notification unit 13 when a condition is satisfied as a result of the determination by the processing unit 12. The condition determined by the processing unit 12 is selected from the first condition and the second condition based on the determination result of the switching condition determined with respect to the smoke density Cs. The first condition is defined for only one of the smoke concentration Cs and the carbon monoxide concentration Cc, and the second condition is defined for both the smoke concentration Cs and the carbon monoxide concentration.

  The switching condition is the magnitude of the difference between the smoke concentration Vs with respect to the predetermined reference time and the first determination value. Further, the first condition includes that the smoke concentration Cs is equal to or higher than the second determination value Vs1 without considering the carbon monoxide concentration Cc. Further, the second condition includes that the smoke concentration Cs is equal to or greater than the second determination value Vs1 in addition to the difference ΔCc related to carbon monoxide being equal to or greater than the third determination value Vc2. When the difference ΔCs regarding smoke is less than the first determination value Vs2, the processing unit 12 selects the first condition, and when the difference ΔCs regarding smoke is greater than or equal to the first determination value Vs2, the processing unit 12 Select the conditions.

  Hereinafter, this embodiment will be described in more detail. In the present embodiment, a fire sensor that detects a fire is exemplified as the sensor 10. The fire detector illustrated includes a body (not shown) used by being attached to a ceiling of a space to be monitored. This fire detector is a smoke-heat composite type that detects whether or not a fire has occurred using three types of information: carbon monoxide (hereinafter referred to as “CO”) concentration, smoke concentration, and temperature. It is configured. In other words, this fire detector is configured to determine whether or not a fire has occurred by monitoring CO and smoke as components of interest in the target space, and also monitoring the temperature together. Yes.

  It is not essential to monitor the temperature of the target space, and the technique of this embodiment is applied to a sensor that focuses only on the concentration of CO, not the two types of components of CO and smoke. Is also possible. Further, the fire detector may be combined with a configuration for detecting a flame by monitoring ultraviolet rays or the like.

  The sensor 10 of this embodiment is provided with the sensor part 11, the process part 12, and the alerting | reporting part 13, as shown in FIG. The sensor unit 11 includes a first sensor 111 that measures smoke concentration, a second sensor 112 that measures CO concentration, and a third sensor 113 that measures temperature. The processing unit 12 determines whether or not a fire has occurred by performing the processing described below.

  The sensor 10 constitutes a sensing system in combination with the alarm device 20. That is, the sensing system includes a sensor 10 described below and a notification device 20 that performs notification using a notification signal output from the notification unit 13. That is, the notification unit 13 outputs a notification signal to the notification device 20 when it is determined in the processing unit 12 that a fire has occurred. The alarm device 20 is provided with at least one of a configuration for performing auditory notification such as a buzzer or a voice synthesizer and a configuration for performing visual notification such as a light emitting diode or a liquid crystal display. That is, when it is determined that a fire has occurred in the processing unit 12, the notification unit 13 notifies the person of the occurrence of the fire through the notification device 20.

  The body of the fire detector forms a space in which smoke is introduced. The first sensor 111 is a photoelectric type that includes a light emitting element that emits light into the space and a light receiving element that receives light from the space, and uses the scattering of light by the smoke to produce a smoke concentration. Is configured to measure. However, the first sensor 111 is configured to output a value corresponding to the light attenuation rate as the smoke concentration. The first sensor 111 is not limited to a configuration that uses light scattering by smoke, but may be a configuration that uses the fact that smoke prevents light transmission. In addition, the first sensor 111 is not limited to the photoelectric type and does not prevent it from being an ionization type.

  As long as the second sensor 112 is configured to measure the CO concentration, there is no particular limitation on the principle of measurement, but it is desirable that the second sensor 112 be low-cost, so an electrochemical sensor is assumed here. The electrochemical sensor includes a detection electrode provided with a catalyst, a counter electrode facing the detection electrode, and an ionic conductor sandwiched between the detection electrode and the counter electrode. This sensor is configured such that charge transfer occurs between the detection electrode and the counter electrode when water vapor in the air and CO react with a catalyst of the detection electrode.

  Since this type of sensor has relatively low sensitivity and accuracy, it has a problem that detection accuracy cannot be ensured in a region where the concentration of CO is small. That is, when this type of sensor is used, it is difficult to judge the CO concentration by an absolute value in a region where the CO concentration is low. In addition, a sensor that measures CO based on other principles is known to have a configuration that can accurately measure even at a low concentration, but it is expensive or large and difficult to adopt at present. The sensor 10 described below makes it possible to detect the presence of CO even in a region where the concentration of CO is low.

  The third sensor 113 is configured to monitor a temperature higher than about 50 ° C., and, for example, a thermistor is employed.

  The processing unit 12 includes an acquisition unit 121 that acquires information measured by the sensor unit 11. The acquisition unit 121 is an interface unit with the sensor unit 11 and converts an analog value acquired for each sensor unit 11 into a digital value. Hereinafter, the digital value corresponding to the first sensor 111 is referred to as smoke concentration, the digital value corresponding to the second sensor 112 is referred to as CO concentration, and the digital value corresponding to the third sensor 113 is referred to as temperature value.

  The processing unit 12 includes a device including a processor that operates according to a program as a main hardware element. This type of device may have a configuration including a memory separately from a device including a processor, in addition to a microcomputer (MicroController) including a memory integrally. The device also functions as the notification unit 13. That is, this program causes the computer to function as the processing unit 12 and the notification unit 13.

  The program is assumed to be written in advance in a ROM (Read Only Memory). However, the program may be written in the ROM by connecting a support device such as a computer. In this case, the program to be provided to the support apparatus may be provided through an electric communication line such as the Internet or provided by a computer-readable recording medium.

  The processing unit 12 includes a determination unit 120 that determines whether or not a fire has occurred using the CO concentration, the smoke concentration, and the temperature value. Further, the processing unit 12 includes a clock unit 122, a storage unit 123, and a counter 124. The determination unit 120 includes a front determination unit 1200, a first determination unit 1201, and a second determination unit 1202 (see FIG. 1).

  The clock unit 122 measures the unit time Tu, and the processing unit 12 determines the timing for acquiring information from the sensor unit 11 based on the unit time Tu. The unit time Tu is set to 1 second, for example. The memory | storage part 123 memorize | stores the information which the acquisition part 121 acquired from the sensor part 11 as needed. The function of the counter 124 will be described later.

  As shown in FIG. 2, the determination unit 120 provided in the processing unit 12 performs a reading process S10, a notification process S20, and a fire determination process S30. The reading process S10 is a process in which the processing unit 12 acquires information from the sensor unit 11 through the acquisition unit 121, and the notification process S20 is a process in which the occurrence of a fire is notified through the notification unit 13. The fire determination process S30 is a process for determining whether or not a fire has occurred using the information acquired from the sensor unit 11 in the reading process S10. The fire determination process S30 is performed by the front determination unit 1200, the first determination unit 1201, and the second determination unit 1202 in the determination unit 120 (see FIG. 1).

  If no fire has occurred, each process circulates in the order of reading process S10 → notification process S20 → fire determination process S30 → reading process S10. That is, it follows a circulating route of link L11 → link L12 → link L13 → link L11. The time for one round of this route is slightly longer than the unit time Tu. As will be described later, the period in which the reading process S10, the notification process S20, and the fire determination process S30 circulate includes various processing times in addition to waiting for the unit time Tu. The time required for other processing is sufficiently shorter than the time for performing the above. Therefore, the period in which the reading process S10, the notification process S20, and the fire determination process S30 are circulated is approximately the same as the unit time Tu.

  On the other hand, when it is determined in the fire determination process S30 that a fire has occurred, a different route is selected according to the timing at which it is determined that a fire has occurred. That is, the occurrence of a fire is notified by any one of a route of fire determination processing S30 → reading processing S10 → notification processing S20 and a route of reading processing S10 → notification processing S20 → fire determination processing S30 → notification processing S20. In other words, when it is determined by the fire determination process S30 that a fire has occurred, notification is performed on either the link L13 → link L11 route or the link L11 → link L12 → link L14 route. After the occurrence of the fire is notified in the notification process S20, the process returns to the reading process S10 through the link L15.

  Hereinafter, each process of the reading process S10, the notification process S20, and the fire determination process S30 will be described in more detail. As illustrated in FIG. 3, in the reading process S <b> 10, the determination unit 120 acquires the temperature value θ from the third sensor 113 through the acquisition unit 121 (S <b> 11), and the smoke concentration from the first sensor 111 through the acquisition unit 121. Cs is acquired (S12). The determination unit 120 may acquire either the temperature value θ or the smoke density Cs first. The acquired smoke concentration Cs is compared with a threshold value Vs0 (for example, 1 [% / m]) for determining whether or not smoke is present (S13). In the present embodiment, the smoke density Cs is represented by the light attenuation rate per meter, and the unit is [% / m].

  When the smoke concentration Cs is equal to or higher than the threshold value Vs0 (S13: yes), the acquisition unit 121 acquires the CO concentration Cc from the second sensor 112 (S15). On the other hand, even if the smoke concentration Cs is less than the threshold value Vs0 (S13: no), if the count value n has reached the reference value Mc (S14: yes), the acquisition unit 121 obtains the CO concentration Cc from the second sensor 112. Obtain (S15). After acquiring the CO concentration Cc (S15), the determination unit 120 resets the count value n to 1 (S16). If the smoke density Cs is less than the threshold value Vs0 (S13: no) and the count value n has not reached the predetermined value Mc (S14: no), the determination unit 120 adds 1 to the count value n ( S17).

  In short, the acquisition unit 121 acquires the CO concentration Cc at any of the following timings. That is, when the smoke concentration Cs is equal to or higher than the threshold value Vs0, the acquisition unit 121 acquires the CO concentration Cc regardless of the count value n. When the state where the smoke concentration Cs is less than the threshold value Vs0 continues until the count value n reaches the predetermined value Mc, the acquisition unit 121 determines that the concentration of CO at the time when the count value n reaches the predetermined value Mc. Get Cc. In other words, when the presence of smoke is detected, the CO concentration Cc is acquired immediately, and when the presence of smoke is not detected, the CO concentration Cc is acquired at a relatively long time interval. When the presence of smoke is not detected, the time interval at which the acquisition unit 121 acquires the CO concentration is Mc times that when the presence of smoke is detected, and Mc is set to about 3 to 10, for example. Is done.

  As described above, when the smoke concentration Cs is acquired and, if necessary, the CO concentration Cc is acquired, the reading process S10 ends. After the reading process S10, the process proceeds to a notification process S20. As shown in FIG. 4, in the notification process S20, the determination unit 120 determines whether or not a fire has already been determined in the fire determination process S30 (S21). As will be described later, the fire determination process S30 sets the fire flag F1 to “1” if it is determined that a fire has occurred, and sets the fire flag F1 to “0” if it is determined that no fire has occurred. .

  If the fire flag F1 is not “1” in step S21 (S21: no), the process proceeds to the fire determination process S30. On the other hand, if the fire flag F1 is “1” in step S21 (S21: yes), there is a high possibility that a fire has occurred, so the determination unit 120 uses the smoke concentration Cs acquired in step S12 as ( The second comparison value Vs1 is compared (S22). The determination value Vs1 is set to a value (for example, 3.5 [% / m]) larger than the threshold value Vs0.

  Here, when the smoke concentration Cs is equal to or higher than the determination value Vs1 (S22: yes), the fire is notified through the notification unit 13 (S26). That is, the processing unit 12 indicates that there is a high possibility that a fire has occurred, and when the smoke concentration Cs is equal to or higher than the determination value Vs1, the processing unit 12 notifies the fire through the notification unit 13.

  On the other hand, even if it is determined that there is a high possibility that a fire has occurred (S21: yes), if the smoke concentration Cs is less than the determination value Vs1 (S22: no), the fire flag F1 is set to “0”. The count value Ic is reset to 0 (S24). The count value Ic is used to count the number of times the determination described later is performed for the CO concentration Cc in the fire determination process S30.

  As described above, after determining that the fire flag F1 is “1” in step S21 and there is a possibility that a fire has occurred, the determination unit 120 determines that the smoke concentration Cs is “fire” in step S22. If the conditions are not satisfied, it is determined that no fire has occurred. After step S24, the process proceeds to a fire determination process S30 to determine whether or not a fire has occurred.

  In the notification process S20, the condition for notifying the fire through the notification unit 13 includes a condition that the fire flag F1 is not “0” after the fire determination process S30 (S25: no). Therefore, the determination unit 120 notifies the fire through the notification unit 13 when any of the following conditions is satisfied (S26). That is, the determination unit 120 is either a condition that the fire flag F1 is “1” and the smoke density Cs is equal to or higher than the determination value Vs1, or a condition that the fire flag F1 is not “0” after the fire determination process S30. When the above is established, a fire is notified (S26).

  If the fire flag F1 is “0” after the fire determination process S30 (S25: yes), it is determined that no fire has occurred. When the fire flag F1 is “0” after the fire determination process S30 (S25: no), the determination unit 120 returns to the reading process S10 after the unit time Tu has elapsed (S27). The unit time Tu is set to 1 second, for example. If the unit time Tu is set to 1 second, the time interval at which the CO concentration Cc is acquired in step S15 during the period in which the smoke concentration Cs is less than the threshold value Vs0 is about Mc seconds. become. Actually, if the processing time of the reading process S10, the notification process S20, and the fire determination process S30 is Tp, it is (1 + Tp) × Mc seconds, but since Tp << 1, the CO concentration Cc is acquired. The time interval is approximately Mc seconds.

  By the way, in the example of the notification process S20 shown in FIG. 4, even when the fire is notified in step S26, the process returns to the reading process S10 after the unit time Tu has elapsed (S27). Therefore, when the determination unit 120 performs the fire notification in step S26, the determination unit 120 returns to the reading process S10 in a state where the fire notification is continued. That is, after the fire notification is performed, the fire notification is continued.

  Note that the notification process S20 may include a process of stopping the notification when the notification of the fire is a false report. That is, when the process proceeds to the notification process S20 after returning to the reading process S10, the fire determination process S30 is performed, and when the fire flag F1 becomes “0” in the fire determination process S30, the notification is stopped. Also good.

  Next, the fire determination process S30 will be described with reference to FIGS. As shown in FIG. 5, the fire determination process S30 is roughly divided into three types of processes. The pre-processing S31 determines the possibility that a fire has occurred only with the temperature value θ obtained from the third sensor 113. The first process S32 determines the possibility of a fire using only the smoke concentration Cs. Further, the second process S33 determines the possibility of a fire using the smoke concentration Cs and the CO concentration Cc. The pre-processing S31 is performed by the pre-determination unit 1200, the first processing S32 is performed by the first determination unit 1201, and the second processing S33 is performed by the second determination unit 1202.

  In other words, the fire determination process S30 includes a pre-process S31 that uses only the temperature value θ, a first process S32 that uses only the smoke concentration Cs, and a CO concentration Cc and smoke in order to determine the occurrence of a fire. And a second process S33 that is used in combination with the density Cs. In the second process S33, if none of the CO concentration Cc, the smoke concentration Cs, and the temperature value θ satisfies the condition, it is determined that no fire has occurred, or whether a fire has occurred. It also includes a process for deciding whether to leave this to the subsequent fire determination process S30. In FIG. 5, “determined” indicates that a fire has occurred, and “indeterminate” indicates that a fire may have occurred but cannot be determined.

  As shown in FIG. 6, the pre-determination unit 1200 that performs the pre-processing S31 compares the temperature value θ acquired from the third sensor 113 with the determination value Vt1, and sets the temperature value θ with respect to a predetermined reference time T1. The difference Δθ is compared with the determination value Vt2 (S311). For example, if the temperature value at time t is expressed as θ (t1) and the difference at time t is expressed as Δθ (t), Δθ (t) = θ (t) −θ (t−T1). The difference Δθ is a difference between two temperature values θ acquired at a time point separated by the reference time T1.

  The temperature gradient can be obtained by dividing the difference Δθ by the reference time T1. Further, if the reference time T1 is set to an appropriate unit time (for example, 60 seconds), the difference Δθ matches the temperature gradient. Therefore, the condition of step S311 may use a temperature gradient instead of the difference Δ with respect to the reference time T1.

  The determination value Vt1 for the temperature value θ is set to about 60 [° C.], for example, and the reference time T1 is set to about 1 to 3 minutes, for example. That is, the determination value Vt1 is set to a temperature value that does not occur except when a fire occurs, and the reference time T1 is set based on the length of a period during which an increase in temperature is observed when a fire occurs.

  By the way, the time interval for the determination unit 120 to acquire the temperature value θ from the third sensor 113 is shorter than the reference time T1 (for example, about 1 second). Therefore, the difference Δθ relating to the temperature is obtained after performing the fire determination process S30 a plurality of times. The processing unit 12 includes a storage unit 123, and the storage unit 123 includes a storage area that stores the temperature value θ every time the acquisition unit 121 acquires the temperature value θ from the third sensor 113. In the storage unit 123, a storage area for storing the temperature value θ functions equivalently to a shift register, and the difference Δθ is obtained as a difference between the first data (oldest data) and the last data (latest data).

  In step S311, it is determined that a fire has occurred when at least one of the conditions θ ≧ Vt1 and Δθ ≧ Vt2 is satisfied, and the fire flag F1 is set to “1” (S34). On the other hand, if neither of the conditions θ ≧ Vt1 or Δθ ≧ Vt2 is satisfied in step S311, in other words, if θ <Vt1 and Δθ <Vt2, it is determined whether or not the temporary determination flag F2 is “1”. (S312).

  Since the reference time T1 for obtaining the difference Δθ is set to be relatively long, the difference Δθ in the period in which the temperature value θ rapidly increases with the occurrence of a fire and the difference Δθ in the period in which the change in the temperature value θ is relatively small. It becomes easy to distinguish the size. As a result, it becomes easy to discriminate between a period in which the temperature value θ suddenly increases with the occurrence of a fire and a period in which the temperature value θ varies little.

  The provisional determination flag F2 is set to “1” when the occurrence of a fire is uncertain and the determination is left to the subsequent fire determination process S30. That is, the provisional determination flag F2 is set to “1” when it cannot be determined that a fire has occurred, but the possibility that a fire has occurred cannot be denied. On the other hand, when it can be determined that no fire has occurred, the front determination unit 1200 sets the temporary determination flag F2 to “0”.

  If the provisional determination flag F2 is not “1” in step S312, the prefix determination unit 1200 compares the difference ΔCs of the density Cs related to smoke with the (first) determination value Vs2 (S313). Similarly to the difference Δθ in temperature value θ, if the smoke concentration at time t is expressed as Cs (t) and the difference in smoke concentration Cs at time t is expressed as ΔCs (t), then ΔCs (t) = Cs (t) − Cs (t−T2). Since the difference ΔCs is the difference in smoke density Cs at the point of time separated by the reference time T2, it is possible to obtain the smoke concentration gradient by dividing by the reference time T2. That is, if the reference time T2 is set to an appropriate unit time (for example, 60 seconds), the difference Cs is equivalent to the concentration gradient related to smoke. Therefore, step S312 may use a concentration gradient instead of the difference ΔCs with respect to the reference time T2.

  The reference time T2 is set to about 30 seconds to 2 minutes. That is, the time is set sufficiently longer than the time interval at which the acquisition unit 121 acquires the smoke density Cs in the reading process S10. However, the difference ΔCs is updated for each fire determination process S30.

  FIG. 9 shows the relationship among the smoke concentration Cs, the reference time T2, and the difference ΔCs. The figure also shows the concentration gradient α2 of the smoke concentration Cs. As shown in the figure, since the reference time T2 is set to be relatively long, even if the smoke concentration Cs varies with time, the tendency of the smoke concentration Cs to change can be determined.

  Here, in order to obtain the difference ΔCs of the density Cs related to the smoke with respect to the reference time T2, the smoke density Cs acquired by the acquisition unit 121 is stored in the storage unit 123 as in the case of obtaining the difference Δθ of the temperature value θ. The That is, the storage unit 123 includes a storage area that stores the density Cs every time the acquisition unit 121 acquires the density Cs from the first sensor 111. In the storage unit 123, the storage area for storing the smoke density Cs functions equivalently to a shift register, and the difference ΔCs is obtained from the first data (oldest data) and the last data (latest data).

  By the way, when the temporary determination flag F2 is “1” in step S312, it is uncertain whether or not a fire has occurred, so it is necessary to determine whether or not a fire has occurred in the subsequent processing. is there. Therefore, if the smoke concentration Cs is less than the threshold value Vs0 continues for the (second) determination time Td2 (S314: yes), the temporary determination flag F2 is set to “0” (S315), and a fire is generated. Confirm that it has not occurred. In other words, if the smoke concentration Cs continues to be less than the threshold value Vs0 during the period in which the fire determination process S30 corresponding to the determination time Td2 is performed (S314: yes), the pre-determination unit 1200 temporarily The determination flag F2 is set to “0” (S315).

  The determination time Td2 is set to a time sufficiently longer than the period (for example, about 1 second) in which the determination unit 120 acquires the smoke concentration Cs from the first sensor 111, and is set to 60 seconds, for example. If the reading process S10, the notification process S20, and the fire determination process S30 are repeated at a cycle of about 1 second, the determination time Td2 corresponds to a time when the fire determination process S30 is performed about 60 times. The threshold value Vs0 is a lower limit value for determining that smoke is generated, and is a value sufficiently smaller than a determination value Vs1 used when determining the occurrence of fire (for example, Vs0≈0.3). -Vs2).

  In step S314, when the smoke concentration Cs is less than the threshold value Vs0 does not continue for the determination time Td2 (S314: no), the process proceeds to the second process S33. That is, when the density Cs becomes equal to or higher than the threshold value Vs0 before the determination time Td2 elapses, the process proceeds to the second process S33. In step S313, when the difference ΔCs of the density Cs related to smoke is less than the determination value Vs2 (or when the density gradient α2 related to smoke is relatively small), the process proceeds to the first process S32. In step S313, when the difference ΔCs is equal to or larger than the determination value Vs2 (or when the concentration gradient α2 regarding smoke is relatively large), the process proceeds to the second process S33.

  In short, the condition [ΔCs ≧ Vs2] in step S313 in the pre-process S31 is a switching condition that determines which of the first process S32 and the second process S33 is selected. When the condition of step S313 is not satisfied (S313: no), the processing unit 12 selects the first process S32. When the condition of step S313 is satisfied (S313: yes), the processing unit 12 selects the second process S33. .

  As described later, the first process S32 and the second process S33 use a count value. Therefore, the processing unit 12 includes a counter 124 that counts the count value. The counter 124 can add and subtract, and the minimum value of the count value is zero. When the fire flag F1 is set to “0” in the notification process S20 (S23), or the temporary determination flag F2 is set to “0” in the fire determination process S30 (S315), the count value of the counter 124 is Returned to zero. The counter 124 is configured to count a count value corresponding to a duration time during which smoke has been detected and a count value corresponding to a duration time during which CO has been detected.

  As described above, the first determination unit 1201 that performs the first process S32 illustrated in FIG. 7 determines the occurrence of a fire using only the smoke concentration Cs. The first determination unit 1201 indicates that the temporary determination flag F2 is “0” (S312: no), and the smoke concentration Cs difference ΔCs is less than the determination value Vs2 (ΔCs <Vs2) (S313: no). Is a prerequisite. This precondition means that no fire has occurred and no change in the smoke concentration Cs was recognized at the determination time Td2. In other words, the precondition of the first process S32 indicates that there is a high possibility that no fire has occurred.

  The condition for determining that a fire has occurred in the first determination unit 1201 is that a state in which the smoke concentration Cs is high continues for a relatively long time (for example, about 10 seconds). The duration of time during which smoke is continuously detected is not limited to the time during which the smoke concentration Cs acquired by the acquisition unit 121 is continuously high. That is, even if the state where the concentration Cs is high is discontinuous, if it is determined that the state where the smoke concentration Cs is high continues, the counter 124 counts a count value corresponding to the duration.

  In the first process S32, the first determination unit 1201 compares the smoke density Cs acquired in the reading process S10 with the determination value Vs1 (S321). When the smoke density Cs is equal to or higher than the determination value Vs1 (S321: yes), the counter 124 adds 1 to the count value Is corresponding to the smoke (S322). When the smoke density Cs is less than the determination value Vs1 (S321: no), 2 is subtracted from the count value Is (S323). The count value Is is used to estimate the duration.

  The count value Is is compared with the reference value Ns (S324). When the count value Is becomes equal to or greater than the reference value Ns (S324: yes), the first determination unit 1201 determines that the state where the smoke concentration Cs is equal to or greater than the determination value Vs1 has continued, and sets the fire flag F1 to “1”. (S34). If the count value Is is less than the reference value Ns (S324: no), the determination unit 120 proceeds to notification processing S20.

  By the way, since the duration is the time until the count value Is reaches the reference value Ns, the state in which the smoke concentration Cs becomes less than the determination value Vs1 before the duration reaches the reference value Ns is allowed. ing. This is because the smoke concentration Cs fluctuates with time, and the smoke concentration Cs temporarily becomes less than the determination value Vs1 even after the smoke concentration Cs exceeds the determination value Vs1 when a fire occurs. This is because it can occur. Since the smoke density Cs is continuously monitored even if the density Cs is temporarily reduced in this way, the occurrence of a fire is detected if the smoke density Cs is continued when a fire is occurring. Misreporting will be prevented.

  On the other hand, if the smoke concentration Cs temporarily exceeds the determination value Vs1 due to smoking or cooking, the count value Is does not reach the reference value Ns, so the reference value Ns is set appropriately. Thus, the occurrence of false alarms is prevented. If the smoke density Cs is less than the determination value Vs1, 2 is subtracted from the count value Is (S323). Therefore, when the smoke density Cs is low, the time until the count value Is reaches the reference value Ns. From this fact, the effect of suppressing false alarms can be expected.

  Incidentally, the second determination unit 1202 that performs the second process S33 uses the CO concentration Cc in addition to the smoke concentration Cs as a condition for determining that a fire has occurred. There are two types of preconditions for the second process S33, and when one of the preconditions is satisfied, the second process S33 is executed. One precondition is that the provisional determination flag F2 is “0” (S312: no), and the difference ΔCs of the density Cs relating to smoke is equal to or greater than the determination value Vs2 (ΔCs ≧ Vs2) (S313: yes). . The other precondition is that the temporary determination flag F2 is “1” (S312: yes) and the smoke density Cs is equal to or higher than the threshold value Vs0 at the determination time Td2 (S314: no). The second process S33 includes a condition relating to the smoke density Cs, regardless of which condition is the precondition.

  After the step S313 or step S314 (S313: yes or S314: no), the second determination unit 1202 that performs the second process S33 illustrated in FIG. 8 calculates the difference ΔCc of the concentration Cc with respect to the predetermined reference time T3 (first step). 3) and a determination value Vc2 (S331). Similar to the reference time T2, the reference time T3 is set to about 30 seconds to 2 minutes, and the difference Cc is updated for each fire determination process S30.

  Here, as the CO concentration Cc, the moving average value of the concentration Cc is used instead of the concentration Cc acquired by the acquisition unit 121 in the reading process S10. The number of the density Cc when calculating the moving average value is preferably about 5 to 15. In other words, the CO concentration Cc is not an individual value acquired by the acquisition unit 121 but an average value of a predetermined number of concentrations Cc that is back by a predetermined time from the time at which the concentration Cc is obtained.

  Now, let the time series of the CO concentration Cc acquired by the acquiring unit 121 be C1, C2,. If the moving average value of 12 concentrations is used as the CO concentration Cc, the moving average value of the concentration Cc is (C1 + C2 +... + C12) / 12, (C2 + C3 +... + C13) / 12, (C3 + C4 +... + C14). / 12, ...

  Since the CO concentration Cc is a moving average value, even when an electrochemical sensor having a relatively low measurement accuracy is employed as the second sensor 112 for measuring the CO concentration, a change occurs in the CO concentration Cc. This can be detected with high accuracy.

  For example, when CO is generated by a fire, the concentration gradient of CO is at least about 1 to 5 ppm / min. When the second sensor 112 is an electrochemical sensor, even if the concentration gradient is calculated from the adjacent concentration Cc in the time series of the CO concentration Cc acquired for each reading process S10, it is sufficient to be used for fire determination. Accurate accuracy cannot be obtained.

  On the other hand, in this embodiment, since the difference ΔCc of the concentration Cc is obtained using the moving average value for the CO concentration Cc, and it is determined whether or not a fire has occurred using the difference ΔCc, the CO concentration It is easy to accurately determine the change in Cc.

  When the difference ΔCc of the concentration Cc related to CO is equal to or larger than the determination value Vc2 (S331: yes), the counter 124 adds 1 to the count value Ic corresponding to CO (S332), and then the smoke concentration Cs is determined as the determination value. It is compared with Vs1 (S334).

  Here, if the concentration of CO at time t is expressed as Cc (t) and the difference of concentration Cc at time t is expressed as ΔCc (t), similarly to the difference ΔCs of concentration Cs related to smoke, ΔCc (t) = Cc (T) -Cc (t-T3). The difference ΔCc is a difference in the CO concentration Cc at a time point separated by the reference time T3.

  The CO concentration gradient can be obtained by dividing the difference ΔCc by the reference time T3. Therefore, if the reference time T3 is set to an appropriate unit time (for example, 60 seconds), the difference ΔCc matches the concentration gradient. Therefore, step S331 may use a concentration gradient instead of the difference ΔCc with respect to the reference time T3. As described above, the reference time T3 is set to be approximately the same as the reference time T2. In order to simplify the internal processing of the processing unit 12, it is desirable that the reference time T3 is the same as the reference time T2.

  FIG. 10 shows the relationship between the CO concentration Cs, the reference time T3, and the difference ΔCc. In the figure, the concentration gradient α3 of the concentration Cs related to CO is also shown. From this figure, if the reference time T3 is appropriately set, even if the accuracy of the concentration Cs in the period of the reference time T3 is insufficient, if a relatively large change occurs in the CO concentration Cc, It can be seen that the change in the CO concentration Cc can be determined.

  In step S334, when the smoke density Cs is equal to or higher than the determination value Vs1 (S334: yes), 1 is added to the counter value Is corresponding to the smoke (S335). When the smoke density Cs is less than the determination value Vs1 (S334: no), 2 is subtracted from the counter value Is corresponding to the smoke (S336). Steps S334 to S336 are the same processes as steps S321 to S323 in the first process S32. After subtracting 2 from the count value Is in step S336, the determination unit 120 proceeds to notification processing S20.

  After step S335, the second determination unit 1202 compares the count value Ic for CO with the reference value Nc (S337). When the count value Ic is equal to or greater than the reference value Nc (S337: yes), the smoke-related count value Is is compared with the reference value Ns (S338). If the count value Is is greater than or equal to the reference value Ns (S338: yes), the second determination unit 1202 sets the fire flag F1 to “1” (S34). When the count value Ic is less than the reference value Nc (S337: no), or when the count value Is is less than the reference value Ns (S338: no), the determination unit 120 proceeds to the notification process S20.

  In the second process S33 shown in FIG. 8, when the difference ΔCc of the concentration Cc relating to CO is less than the determination value Vc2 in step S331 (S331: no), 2 is subtracted from the count value Ic corresponding to CO in the counter 124. (S333). Further, after step S333, it is determined whether or not the state in which the smoke difference Cc difference ΔCc is equal to or greater than the determination value Vs2 continues for the (first) determination time Td1 (S339).

  If the state in which the smoke difference Cs difference ΔCs is equal to or greater than the determination value Vs2 continues during the period in which the fire determination process S30 is performed the number of times corresponding to the determination time Td1 (S339: yes), the temporary determination flag F2 is “1”. (S340). When the time during which the difference ΔCs is equal to or greater than the determination value Vs2 does not reach the determination time Td1, or after step S340, the determination unit 120 returns to the notification process S20.

  Here, the determination time Td1 is set to determine the duration of the state in which the smoke concentration Cs increases rapidly. When the generation of smoke is caused by a fire, the time during which the smoke concentration Cs rapidly increases continues for more than about 10 seconds. Therefore, the determination time Td1 is also set to about 10 seconds. That is, the (second) determination time Td2 used by the front determination unit 1200 is set to be longer than the (first) determination time Td1 used by the second determination unit 1202.

  As described above, in the fire determination process S30, the pre-process S31 not only determines the occurrence of a fire using the temperature value θ, but also sets preconditions for the first process S32 and the second process S33. ing. For the first process S32, it is defined as a precondition that there is little change in smoke concentration Cs (ΔCs <Vs2) in a state where it is determined that no fire has occurred (F2 = 0). . In addition, two types of preconditions are defined for the second process S33. One precondition is that the smoke concentration Cs rapidly increases (ΔCs ≧ Vs2) in a state where it is determined that no fire has occurred (F2 = 0). Further, the other precondition is that it is not determined whether or not a fire has occurred (F2 = 1), and the generation of smoke is continuously detected at the determination time Td2.

  As described above, the prefix determination unit 1200 compares the difference ΔCs of the density Cc related to smoke with the first determination value Vs2 in step S313, and selects the first determination unit 1201 if ΔCs <Vs2. , ΔCs ≧ Vs2, the second determination unit 1202 is selected. The first determination unit 1201 determines the smoke concentration Cs without considering the carbon monoxide concentration Cs. The second determination unit 1202 determines the smoke concentration Cs in addition to the difference ΔCc of the carbon monoxide concentration Cc.

  Further, in the second process S33, the processing unit 12 determines that the provisional determination flag F2 is set when the state where the difference ΔCs of the smoke-related density Cs is equal to or greater than the (first) determination value Vs2 continues for the first determination time Td1. It becomes “1”. As a result, the prefix determination unit 1200 interrupts the process of comparing the smoke concentration Cs difference ΔCs with the first determination value Vs2. Therefore, the second determination unit 1202 continues the second process S33.

  Here, in the pre-processing shown in FIG. 6, the pre-determination unit 1200 is configured not to determine whether or not the switching condition [ΔC ≧ Vs 2] is satisfied when the temporary flag F <b> 2 is “1”. However, a configuration for determining the switching condition may be employed. However, even if the pre-determination unit 1200 determines the switching condition, if the temporary flag F2 is “1”, the pre-determination unit 1200 sets the second determination unit 1202 regardless of whether or not the switching condition is satisfied. Configure to select. As is apparent from this operation, the temporary flag F2 is a function for delivering the determination result that the condition determined by the second processing unit 1202 [ΔCs ≧ Vs2 continues for the determination time Td1] to the preprocessing unit 1200. Have

  The second determination unit 1202 has the smoke concentration Cs equal to or greater than the (second) determination value Vs1 in addition to the difference ΔCc of the concentration Cc related to carbon monoxide being equal to or greater than the (third) determination value Vc2. It is determined whether a condition including the above is satisfied. Here, when the state in which the smoke density Cs is less than the threshold value Vs0 continues for the (second) determination time Td2, the front determination unit 1200 performs the first determination unit 1201 and the second determination according to the switching condition. The unit 1202 is selected again. In the operation example shown in FIG. 6, in step S313, the process returns to the state in which the process of comparing the difference ΔCs of the density Cs regarding smoke with the (first) determination value Vs2 is performed.

  The threshold value Vs0 is set such that the determination value Vs1 with respect to the smoke density Cs and the determination value Vs2 with respect to the difference ΔCs between the smoke density Cs are Vs0 <Vs1−Vs2. This is because the smoke determination immediately after the predetermining unit 1200 sets the temporary determination flag F2 to “0” from the state where the temporary determination flag F2 is set to “0”, and immediately after returning to the process passing through step S313. This is to prevent Cs from reaching the determination value Vs1 or more. When the threshold value Vs0 is equal to or greater than (Vs1−Vs2), even if the difference ΔCs is less than the determination value Vs2 in step S313, (Vs0 + Vs2) is equal to or greater than the determination value Vs1. That is, the smoke density Cs becomes equal to or higher than the determination value Vs1, and 1 is added to the count value Is corresponding to the smoke. On the other hand, in this embodiment, since the threshold value Vs0 is (Vs1−Vs2) or less, (Vs0 + Vs2) is less than the determination value Vs1 in step S313, and addition to the count Is corresponding to smoke is prevented.

  By the way, the mode of the fire changes depending on various factors such as the type of the substance combusted at the time of the fire and the environment of the place where the fire occurs. Such fire modes are categorized into about 10 types. With regard to temporal changes in smoke concentration Cs and CO concentration Cc due to fire, there is a case where the fire suddenly rises in a short time and a time that is relatively long. It is known that it rises slowly. In addition, the concentrations Cs and Cc may be increased to a relatively high value, increased only to a relatively low value, saturated, or decreased and then decreased depending on the fire mode.

  Further, the time from when the fire occurs until the concentrations Cs and Cc start to rise also differs depending on the mode of the fire. Although the timing at which the smoke concentration Cs and the CO concentration Cc rise may be different, it is generally known that a similar tendency is seen in the timing at which the smoke concentration Cs and the CO concentration Cc rise. ing. The fire detector is required to detect the occurrence of the fire within about 10 minutes after the occurrence of the fire. As described above, it is necessary for the fire detector to determine the occurrence of a fire within a time of about 10 minutes for various types of fire.

  In the configuration example described above, out of the fire determination processing S30, the first processing S32 can detect the occurrence of a fire in a mode in which the smoke concentration Cs rises continuously and gradually. In addition, a fire in a mode in which the smoke concentration Cs rapidly increases can be detected by the second process S33. In the second process S <b> 33, regarding the fire in which the smoke concentration Cs rises rapidly, the occurrence of the fire is determined in consideration of the increasing tendency of the CO concentration Cc. Even when the CO concentration Cc is relatively small, it may be determined that a fire has occurred if the CO concentration Cc difference ΔCc is greater than or equal to the determination value Vc2.

  That is, in the second process S33, even when the CO concentration Cc is relatively small, if the difference Cc of the concentration Cc related to CO is relatively large, the fire determination process is repeated while the fire determination process S30 is repeated a plurality of times. It is possible to do. In this process, the condition for determining that a fire has occurred includes that the state where the smoke concentration Cs is equal to or higher than the determination value Vs1 is continued. That is, it is determined that the fire has occurred in the second process S33 because the smoke concentration Cc continues to be relatively high, the smoke concentration Cs rapidly increases, and the concentration related to CO It becomes a fire of the aspect which continues the state where Cc rises.

  In the second process S33, when the smoke concentration Cs increases rapidly only for a short time, and the difference Cc in the concentration Cc with respect to CO is relatively small, it is not determined that there is a fire. Such an event is assumed to occur due to white smoke or steam generated from dry ice, and the second process S33 may distinguish white smoke or steam generated from dry ice from smoke due to fire. It becomes possible.

  In other words, when the state in which the smoke concentration Cs rapidly increases continues for a relatively long time, the possibility that a fire has occurred cannot be denied even if the difference ΔCc of the concentration Cc with respect to CO is relatively small. Therefore, in such a case, the temporary determination flag F2 is set to “1”, and the determination result is left to the subsequent fire determination process S30.

  FIG. 11 shows an example of a change in the measured value (concentration Cs) when the first sensor 111 measures steam generated from an electric pot (so-called electric kettle) that does not have a heat retaining function. In the figure, the time from when the smoke concentration Cs rises to the time t4 is about 6 minutes. Further, the maximum value of the concentration Cs in the figure is about 15% / m.

  By the way, in the example shown in FIG. 11, it is assumed that the smoke density Cs is equal to or higher than the threshold value Vs0 in almost the entire period up to time t4. In this example, in step S311 in the fire determination process S30, the temperature value θ does not satisfy the condition when a fire is occurring. That is, the process proceeds from step S311 to step S312.

  Further, in the illustrated example, the generation of steam is started, and the concentration Cs increases from the time when the concentration Cs becomes equal to or higher than the threshold value Vs0 to the time t3, and the concentration Cs decreases from the time t3 to the time t4. It is a period. Furthermore, time t1 represents a time point when the condition [ΔCs ≧ Vs2 is determined to continue for determination time Td1] in step S339 of the fire determination process S30 is satisfied, and at this point, the temporary determination flag F2 becomes “1”. Time t2 represents the time when the condition [Cs <Vs0 continues for determination time Td2] in step S314 is satisfied after time t1. Therefore, time t1 corresponds to the time when the determination time Td1 has elapsed since the smoke concentration Cs became equal to or greater than the threshold value Vs0, and time t2 corresponds to the time when the determination time Td2 has elapsed thereafter.

  In the illustrated example, after the condition [Cs ≧ Vs0] in step S13 of the reading process S10 is satisfied, the process proceeds to the second process S33 when the condition [ΔCs ≧ Vs2] in step S313 of the fire determination process S30 is satisfied. doing. However, until the time t1, the condition of step S339 [ΔCs ≧ Vs2 continues the determination time Td1] is not satisfied, so the second process S33 is selected through steps S312 and S313.

  If this state continues until the determination time Td1 elapses, the provisional determination flag F2 becomes “1” because the condition of step S339 is satisfied. Therefore, in the subsequent fire determination process S30, the condition [F2 = 1] in step S312 is satisfied, and step S314 is selected. Here, since the state where the smoke concentration Cs is high continues, the condition of step S314 [Cs <Vs0 continues for the determination time Td2] is not satisfied, and the state where the temporary determination flag F2 is “1” is maintained. Thus, the second process S33 is selected (see FIG. 6).

  This state continues until the provisional determination flag F2 becomes “0”. After the time t3, the smoke density Cs decreases after the time t3, and the condition [ΔCs ≧ Vs2 continues the determination time Td1] in step S339 is not satisfied, but the temporary determination flag F2 is maintained at “1”. . Therefore, the condition [F1 = 1] in step S312 is satisfied, and further, the condition [Cs <Vs0 continues for the determination time Td2] in step S314 is not satisfied, so the second process S33 is selected even after time t3. .

  At time t4, since the condition [F1 = 1] in step S312 is satisfied and the condition [Cs <Vs0 continues for the determination time Td2] is also satisfied in step S314, the process proceeds to step S315 and the temporary determination flag is set. F2 becomes “0”. Thereafter, the first process S32 is selected through step S313, but the smoke concentration Cs has already decreased, and the condition [Cs ≧ Vs1] of step S321 is not satisfied, so the count value Is corresponding to the smoke is Does not increase. That is, since the condition [Is ≧ Vs1] in step S324 is not satisfied, the fire flag F1 does not become “1”, and the occurrence of false alarm can be avoided.

  In short, when CO is not detected, such as steam in the electric pot, the second process S33 is mainly selected in the fire determination process S30, and if the CO is not detected, the temporary determination flag F2 is set to “1”. Thus, the state that is temporarily determined as steam is continued. If the provisional determination flag F2 is “1”, step S313 is not selected until the smoke density Cs falls below the threshold value Vs0, so the second process S33 is always selected. As a result, the state in which the temporary determination flag F2 is “1” and the second process S33 is selected is maintained until the smoke concentration Cs is reduced unless CO is detected, thereby preventing the occurrence of false alarms.

  If the temporary determination flag F2 is not used in the fire determination process S30, the determination in step S313 is always performed. In this case, even if the smoke concentration Cs starts to decrease at time t3, the condition [ΔCs ≧ Vs2] in step S313 is not satisfied, so the process proceeds to the first process S32, and the condition [Cs ≧ Vs1] is satisfied. As a result, the count value Is corresponding to smoke increases every time the fire determination process is performed, and the fire flag F1 becomes “1”. That is, in the notification process S20, a fire is notified through the notification unit 13 (S26), and a false alarm is generated. In the configuration of the present embodiment, such a false alarm is prevented by the configuration described above.

  FIG. 12 shows an example in which the smoke concentration Cs changes periodically. The illustrated example shows an example in which a state in which the smoke concentration Cs temporarily increases periodically occurs. That is, the smoke density Cs shown changes in a bell shape at the period Tp. The smoke density Cs becomes maximum at the period Tp, and the difference ΔCp between the maximum values becomes relatively small. In the illustrated example, it is assumed that the maximum value of the smoke concentration Cs is equal to or greater than the determination value Vs1, and the period Tp and the determination time Td2 have a relationship of Tp≈Td2. Further, it is assumed that the period Tp is substantially equal to the reference times T2 and T3.

  When the smoke concentration Cs changes as shown in FIG. 12, it is highly possible that the cause of the smoke is not a fire. When the smoke concentration Cs changes as shown in FIG. 12, according to the configuration of the present embodiment, the condition of step S314 of the fire determination process S30 [the state of Cs <Vs0 continues the determination time Td2] is not satisfied. The process proceeds to the second process S33. If CO is not detected, the process passes through step S339, but the condition of ΔSs ≧ Vs2 does not satisfy the condition of determination time Td1. Therefore, both the fire flag F1 and the temporary determination flag F2 are set to “0”. Kept.

  Further, when CO is detected, there is a possibility of passing through step S334. However, since the smoke concentration Cs changes periodically, the smoke concentration Cs continues to satisfy the condition [Cs ≧ Vs1] in step S334. Is never satisfied. Therefore, both the fire flag F1 and the temporary determination flag F2 are kept at “0”.

  As described above, when the smoke concentration Cs periodically changes as shown in FIG. 12, it is not determined that there is a fire, and the occurrence of false alarms is suppressed. Similarly, even when steam from the bathroom continuously stays at the dressing room or when dust stays for a long time, the occurrence of false alarms is suppressed by not detecting CO.

  In the configuration example described above, the second sensor 112 that measures the CO concentration is an electrochemical sensor, and the moving average value of the CO concentration Cc is used to obtain the difference ΔCc of the CO concentration Cc. Yes. However, when the measurement accuracy of the second sensor 112 is relatively good, a configuration in which the difference ΔCc obtained directly from the concentration Cc measured by the second sensor 112 is used without using the moving average value of the CO concentration Cc. It is also possible to adopt. The reference time T2 is the time for the acquisition unit 121 to acquire the smoke concentration Cs from the first sensor 111, and the reference time T3 is the acquisition time for the acquisition unit 121 to acquire the carbon monoxide concentration Cc from the second sensor 112. However, this time can be extended as appropriate.

  Although not described in the configuration example described above, it is desirable to add a reset process separately in case a false alarm occurs.

  In the configuration example described above, the notification device 20 is operated by the notification signal output from the notification unit 13, and the sensor unit 11, the processing unit 12, the notification unit 13, and the notification device 20 are provided in a common body. It is assumed that On the other hand, the structure which the alerting | reporting device 20 isolate | separates and provides in another container, and the alerting | reporting part 13 outputs an alerting | reporting signal to the alerting | reporting device 20 by communication may be sufficient.

  It is also possible to employ a configuration in which a receiver for monitoring the occurrence of a fire is used instead of the alarm 20 and a plurality of fire detectors are connected to the receiver and an alarm signal is output to the receiver. It is. This type of receiver centrally manages a plurality of fire detectors and has a function of monitoring whether or not a fire has occurred at each place where the fire detectors are arranged in a building or the like.

DESCRIPTION OF SYMBOLS 10 Sensor 11 Sensor part 12 Processing part 13 Notification part 111 1st sensor 112 2nd sensor 120 Determination part 1200 Preliminary determination part 1201 1st determination part 1202 2nd determination part

Claims (9)

A first sensor for measuring the concentration of smoke in the air;
A second sensor for measuring the concentration of carbon monoxide in the air;
A processing unit that determines whether or not a predetermined condition is satisfied with respect to the smoke concentration measured by the first sensor and the carbon monoxide concentration measured by the second sensor;
A notification unit that outputs a notification signal when the condition is satisfied;
The processor is
One of a first condition defined for only one of the smoke concentration and the carbon monoxide concentration and a second condition defined for both the smoke concentration and the carbon monoxide concentration, The sensor is selected based on a determination result of a switching condition defined for the smoke concentration. The processor is
A pre-determination unit that determines the difference between the smoke density difference with respect to a predetermined reference time and the first determination value as the switching condition;
A first determination unit that determines whether or not the first condition including that the smoke concentration is equal to or higher than a second determination value without considering the concentration of carbon monoxide;
In addition to the difference regarding the carbon monoxide being equal to or greater than a third determination value, it is determined whether or not the second condition including that the smoke concentration is equal to or greater than a second determination value is satisfied. A second determination unit,
The pre-determination unit selects the first determination unit when it is determined that the difference regarding the smoke is less than the first determination value, and the difference regarding the smoke is equal to or greater than the first determination value. The sensor according to claim 1, wherein the second determination unit is selected when it is determined. The prefix determination unit
When the state where the smoke-related difference is equal to or greater than the first determination value continues for the first determination time, the second determination unit is selected regardless of whether or not the switching condition is satisfied. And whether or not a condition including that the smoke concentration is equal to or higher than the second determination value in addition to the difference regarding the carbon monoxide being equal to or higher than the third determination value is determined. The sensor according to claim 2. The prefix determination unit
When the state where the smoke concentration is less than the predetermined threshold continues for the second determination time, one of the first determination unit and the second determination unit is determined based on the determination result of the switching condition. The sensor according to claim 3, wherein the sensor is returned to a selected state. The sensor according to claim 4, wherein the second determination time is set to be longer than the first determination time. The smoke and the concentration of carbon monoxide in the air are acquired from the sensor unit, and the processing unit determines whether or not a predetermined condition is satisfied for the acquired smoke and carbon monoxide concentrations, A method for outputting a notification signal from a notification unit when a condition is satisfied,
One of a first condition defined for only one of the smoke concentration and the carbon monoxide concentration and a second condition defined for both the smoke concentration and the carbon monoxide concentration, The sensing method, wherein the processing unit selects the condition based on a determination result of a switching condition defined for the smoke density. The switching condition is the magnitude of the difference in the smoke concentration with respect to a predetermined reference time and the first determination value,
The first condition includes that the smoke concentration is not less than the second determination value without considering the carbon monoxide concentration,
The second condition includes that the difference with respect to the carbon monoxide is not less than a third determination value, and that the smoke concentration is not less than a second determination value.
When the difference regarding the smoke is less than the first determination value, the processing unit selects the first condition, and when the difference regarding the smoke is equal to or greater than the first determination value, the processing unit The sensing method according to claim 6, wherein the second condition is selected. The sensor according to any one of claims 1 to 5,
A sensing system comprising: a notification device that performs notification using the notification signal output by the notification unit.   The program for making a computer function as the said process part and the alerting | reporting part in the sensor of any one of Claims 1-5.

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