JP2013004026A - Alarm - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an alarm capable of shortening the detection delay time and reducing consumption of a battery.SOLUTION: In a gas alarm, while sampling is performed with a period of 30 seconds, a sampling period is changed so as to be shortened by 10 seconds when a microcomputer 10 detects that gas concentration changes from a permission point or lower to a logic start point or higher in one time of sampling cycle (adjacent front and rear sampling points).

Description

  The present invention relates to an alarm device that measures and alerts the concentration of a target gas in an atmosphere, and more particularly to an alarm device that shortens a detection delay time.

  An alarm device that measures and alarms the concentration of the target gas in the atmosphere is configured so that the gas concentration in the sensor detector is the concentration of the ambient gas outside the alarm device due to the structure around the sensor that is the gas detection means, the sensor structure, the filter in the sensor, etc. It may take some time to reach

  In addition to the delay due to the structure, a delay due to driving of the sensor also occurs. In particular, a battery-type alarm device may be intermittently driven as described in Patent Document 1 to increase the sampling cycle, which is a sensor driving interval, from the relationship of battery life. In this case, the time until the alarm becomes longer depending on the sampling timing, and it may take time to warn the user of gas leakage or the like.

JP 2008-204240 A

  In order to solve the above-described problem, it is conceivable to simply shorten the sampling cycle. In this case, however, current consumption due to sensor driving increases and the number of batteries increases.

  Further, when the sampling period is changed according to the gas concentration as in the gas alarm device described in Patent Document 1, if the concentration change is slow as shown in FIG. A lot of samples are wasted. FIG. 7 is a graph showing an example of changes in gas concentration over time, where the alarm point is the concentration at which an alarm is issued, and the starting point is the concentration that shortens the sampling period. In FIG. 7, the sampling period is shortened because the concentration exceeds the starting point. However, since the subsequent concentration change is slow, an alarm is not generated, resulting in excessive sampling with respect to the concentration change, resulting in exhaustion of the battery. Resulting in.

  Therefore, an object of the present invention is to provide an alarm device that can reduce detection delay time and reduce battery consumption.

  The invention according to claim 1, which has been made to solve the above problems, includes a gas detection unit that detects a target gas in an atmosphere, a gas concentration measurement unit that measures a concentration of a gas detected by the gas detection unit, and An alarm device comprising: a control unit that causes a gas concentration measurement unit to measure at a predetermined sampling period; and an alarm unit that outputs an alarm according to the concentration measured by the gas concentration measurement unit, wherein the control unit includes the alarm When the means detects that the concentration measured by the gas concentration measuring means is less than the concentration that outputs an alarm and the concentration measured by the gas concentration measuring means has changed more than a predetermined concentration at adjacent sampling points, the sampling cycle is changed to be shortened. This is an alarm device.

  According to a second aspect of the present invention, in the first aspect of the present invention, the control means includes a first determination point that is less than a concentration at which the alarm means outputs an alarm, and the first determination point. A second determination point having a concentration that is lower than a predetermined concentration change is set, and the control means sets the first determination point from a concentration equal to or lower than the second determination point during one sampling period. When it is detected that the concentration has changed to a level equal to or higher than the determination point, the sampling period is changed to be shortened.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the number of times of measurement in a short sampling period is determined in advance in the control unit, and the control unit performs the measurement after the predetermined number of times is measured. It is characterized by returning to the sampling period before the change to the shortened sampling period.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the control unit causes the gas concentration measuring unit to measure the concentration with a shortened sampling period. When the warning means outputs a warning, the sampling period before the change to the shortened sampling period is restored.

  As described above, according to the first aspect of the present invention, the control means determines the concentration measured by the gas concentration measuring means in the sampling period before and after the alarming means is less than the concentration at which the alarm means outputs an alarm. When it is detected that a change over the concentration has occurred, the sampling period of the gas concentration measuring means is changed to shorten the sampling period, so that the sampling period can be shortened only when there is a steep gas concentration change. In addition to shortening the detection delay time due to a steep gas concentration change, the sampling cycle is changed only for the steep gas concentration change, so that battery consumption can be reduced. In addition, when a sudden gas change is detected, it is considered that there is a high possibility that the user will be in a dangerous state, such as exceeding the lower limit of explosion at once, so by shortening the sampling period and making an alarm early, It is possible to promptly notify the user that the user is in a dangerous state.

  According to the second aspect of the present invention, the control means includes a first determination point that is less than a concentration at which the alarm means outputs an alarm, and a concentration that is lower than a predetermined change in concentration from the first determination point. A certain second determination point is set, and the control means determines that the control means has changed from a density lower than the second determination point to a density higher than or equal to the first determination point during one sampling period. If detected, the sampling period is changed so as to be shortened. Therefore, when the gas concentration changes from the second determination point or less to the first determination point or more in one sampling period, the gas concentration is changed in advance. A change exceeding the predetermined concentration has occurred, and the sampling period can be shortened as a steep gas concentration change.

  According to the invention described in claim 3, the number of times of measurement with a short sampling period is determined in advance in the control means, and the control means sets the sampling period before changing to the shortened sampling period after the predetermined number of times measurement. Therefore, the number of times the concentration is measured in a short sampling cycle can be limited, and battery consumption can be reduced.

  According to the invention described in claim 4, when the alarm means outputs an alarm when the control means causes the gas concentration measuring means to measure the concentration in the shortened sampling cycle, the control means changes to the shortened sampling cycle. Since it returns to the previous sampling period, it is not necessary to shorten the sampling period after the warning is output, so it is not necessary to shorten the sampling period, and to reduce battery consumption by returning to the normal sampling period be able to.

It is a principal part block diagram of the gas alarm device concerning one Embodiment of this invention. It is the flowchart which showed the processing operation at the normal time of the gas alarm device shown by FIG. It is the flowchart which showed the detection delay process shown by FIG. It is the graph which showed the relationship between the output voltage of a gas sensor, and time. It is the graph which showed the relationship between the output voltage of a gas sensor on the conditions different from FIG. 4, and time. It is the graph which showed the case where the density | concentration of gas falls temporarily. It is the graph which showed the case where the density | concentration change of gas is gentle.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a principal block diagram of a gas alarm device as an alarm device according to an embodiment of the present invention. As shown in FIG. 1, the gas alarm device supplies power to the gas sensor 1, a microcomputer (hereinafter referred to as a microcomputer) 10, an amplifier circuit 20, a sound alarm output circuit 30, and each part of the gas alarm device. A battery 40, an EEPROM 50 as a nonvolatile memory, and a communication interface (I / F) 60 are provided.

The gas sensor 1 as the gas detection means detects the concentration of a gas such as carbon monoxide (CO), methane (CH ₄ ), or hydrogen (H ₂ ). For the gas sensor 1, for example, an arbitrary method may be selected according to the type and number of gases to be detected, such as a well-known semiconductor method or electrochemical method.

  The microcomputer 10 serving as the gas concentration measuring means and the control means includes a CPU 10a that performs various processes according to a processing program, a ROM 10b that stores a program for processing performed by the CPU 10a, a work area that is used in various processing steps in the CPU 10a, A RAM 10c having a data storage area for storing various data, etc., a timer 10d for measuring the time set in a predetermined register or measuring the date and time, the time, etc. are constituted by a bus line. It is connected. Then, the microcomputer 10 measures the concentration of a predetermined gas by the voltage signal output from the gas sensor 1 via the amplifier circuit 20 at the sampling period set in the timer 10d, and the concentration of the gas becomes equal to or higher than the alarm point. Occasionally, the audio alarm output circuit 30 is instructed to issue an alarm, and the alarm is instructed to stop when the alarm release point is reached.

  The voice alarm output circuit 30 as an alarm means issues an alarm according to an instruction from the microcomputer 10 or stops the issued alarm. The alarm means is not limited to sound output, and may be a blinking lamp, a buzzer or the like, or a combination thereof. The EEPROM 50 stores various parameters for operating the microcomputer 10 such as a sampling period set in the timer 10d. The communication interface 60 is an interface for connecting an external device or communicating wirelessly or the like, and can output the contents stored in the EEPROM 50 to the outside or rewrite the contents of the EEPROM 50 from the outside.

  Next, the operation of the gas alarm device having the above-described configuration will be described with reference to the flowcharts of FIGS. 2 is an operation for performing sampling at a cycle of 30 seconds, which is a normal process, and FIG. 3 is an operation for performing sampling at a cycle of 10 seconds, which is executed when the detection delay processing step of FIG. 2 is entered. Both flowcharts are executed by the microcomputer 10.

  First, in step S11 of FIG. 2, the sampling period of 30 seconds is counted, and if 30 seconds have elapsed, the process proceeds to step S12.

  Next, in step S12, density measurement is performed, and the process proceeds to step S13. That is, the concentration of the gas detected by the gas sensor 1 is measured once every 30 seconds of the sampling period.

  Next, in step S13, it is determined whether or not the alarm point is exceeded. If it is the alarm point or more (in the case of Yes), the process proceeds to step S17 to issue an alarm, and if it is not over the alarm point (in the case of No). Advances to step S14. Of course, the alarm point indicates the concentration at which the gas alarm should issue an alarm. In addition, after issuing a warning in step S17, it returns to step S11.

  Next, in step S14, it is determined whether or not it is greater than or equal to the logic start point described later. If it is greater than or equal to the logic start point (in the case of Yes), the process proceeds to step S15 and is not greater than or equal to the logic start point as the first determination point. In the case (No), the process returns to step S11. The logic start point indicates the concentration at which the detection delay process shown in FIG. 3 is started, and this logic start point is set to a concentration less than the alarm point.

  Next, in step S15, it is determined whether or not the concentration measured last time is equal to or lower than the permission point as the second determination point. If the concentration is equal to or lower than the permission point (in the case of Yes), the process proceeds to step S16. If not (No), the process returns to step S11. The permission point indicates a density provided for detecting a steep change in density, and this permission point is lower than a logic start point so that it can be determined that the change is steeper than the logic start point, that is, from the logic start point. The density is set to be lower than the predetermined density change.

  Next, in step S16, the detection delay logic is activated (executed), and the process returns to step S11. The operation of the detection delay logic will be described with reference to FIG.

  First, in step S21, the sampling period of 10 seconds is counted, and when 10 seconds have elapsed, the process proceeds to step S22. That is, since it is determined in step S15 that the concentration has changed by a predetermined value or more, the sampling period is changed to be shortened.

  Next, in step S22, density measurement is performed and the process proceeds to step S23. That is, the concentration of the gas detected by the gas sensor 1 is measured once every 10 seconds of the sampling period.

  Next, in step S23, it is determined whether or not the alarm point is equal to or higher than the alarm point. If the alarm point is equal to or higher than the alarm point (in the case of Yes), the process proceeds to step S24. Advances to step S25. Then, after issuing an alarm in step S24, the process proceeds to step S27 so as to escape from the detection delay logic as described later. That is, when an alarm is output, the sampling period before the change to the shortened sampling period is restored.

  Next, in step S25, it is determined whether or not it is the second detection delay determination. If it is the second detection delay determination (in the case of Yes), the process proceeds to step S27. Otherwise (in the case of No), the process proceeds to step S26. Proceed to In the second detection delay determination, it is determined whether or not the sampling of the 10-second period is the second time. If it is the second time, the process proceeds to step S27 as will be described later so as to escape from the detection delay logic. Yes. That is, after a predetermined number of measurements, the sampling period before the change to the shortened sampling period is restored.

  Next, in step S26, it is determined whether or not it is higher than the logic release point. If it is higher than the logic release point (in the case of Yes), the process returns to step S21. Proceed to S27. The logic release point is a density setting point for exiting (canceling) the detection delay logic. For example, the logic release point has the same density as the logic start point.

  Next, in step S27, the detection delay logic is stopped, that is, the process returns to the flowchart of FIG.

  Here, the operation example of the above-described flowchart will be described with reference to FIG. FIG. 4 is a graph showing the relationship between the output voltage of the gas sensor 1 and time. Since the output voltage of the gas sensor varies depending on the gas concentration, the output voltage indicates the gas concentration. In FIG. 4, the concentration of gas increases as the output voltage increases.

  A curve L in FIG. 4 is a curve showing a change in the output voltage of the gas sensor 1, that is, the gas concentration over time when an alarm is installed in a gas having a predetermined concentration. A dotted line indicates an alarm point, a one-dot chain line indicates a logic start point, and a two-dot chain line indicates a permission point.

  The gas alarm device described above measures the gas concentration at a sampling period of 30 seconds at the start. In FIG. 4, the concentration at the first measurement time of 30 seconds exceeds the logic start point, and changes from the concentration below the permission point to the concentration above the logic start point in one cycle. In addition, the sampling period is changed to 10 seconds (No in step S13, Yes in step S14, Yes in step S15 in the flowchart of FIG. 2). Since the concentration at the time of 40 seconds, which is the sampling time after 10 seconds, exceeds the alarm point, an alarm is issued and the sampling cycle is returned to 30 seconds (Yes in step S23 in the flowchart of FIG. 3). .

  When the sampling cycle is returned to 30 seconds, the next sampling time is 60 seconds, which is the second sampling time in the 30-second cycle. In other words, in the present embodiment, the sampling period (30 seconds) at the start of startup is continuously performed in the background only after the changed sampling period (10 seconds), and the sampling period has returned. In this case, the gas concentration is measured at the sampling time immediately after returning (in FIG. 4, 30 × n seconds, n is an integer of 1 or more).

  Also, as shown in the graph of FIG. 5, the sampling period (10 seconds) that is changed when changing from the permission point or lower to the logic start point or higher is limited to twice. By doing this, a quick alarm can be given due to a sharp change in density, and thereafter, the density change becomes gentle as shown in FIG. 7, for example, and sampling is performed excessively with respect to the density change. Can be prevented and battery consumption can be reduced. Note that the number of times of the shortened sampling period is not limited to two, and may be arbitrarily changed according to the amount of battery consumption or the installation location.

  According to the above embodiment, in the gas alarm device, when sampling is performed at a cycle of 30 seconds, the concentration from the concentration below the permission point to the concentration above the logic start point in one sampling cycle (adjacent sampling points before and after). If the microcomputer 10 detects that the sampling period has changed, the sampling period is changed to be shortened to 10 seconds. Therefore, the sampling period can be shortened only when there is a steep density change. In addition to shortening the detection delay time due to the change, the sampling period is changed only for a steep density change, so that battery consumption can be reduced. In addition, when a sudden gas change is detected, it is considered that there is a high possibility that the user will be in a dangerous state, such as exceeding the lower limit of explosion at once, so by shortening the sampling period and making an alarm early, It is possible to promptly notify the user that the user is in a dangerous state.

  In addition, since the sampling cycle (10 seconds) that is changed when it changes from the permission point or less to the logic start point or more is limited to twice, a rapid alarm can be given due to a sharp concentration change, and then It is possible to prevent the battery from being exhausted by preventing the sampling from being performed excessively due to a gradual change in density.

  In addition, if an alarm is issued after the sampling period is reduced to 10 seconds, the original 30-second sampling period is restored, so that the user is notified of the danger after the alarm is output. There is no need to keep the cycle short, and the battery can be consumed less by returning to the normal sampling cycle.

  In the above-described embodiment, the logic release point is set to the same density as the logic start point. However, for example, as shown in FIG. 6, hysteresis is provided by setting the logic release point to a density lower than the logic start point. It is possible to prevent the detection delay logic from leaving the operation even if the concentration temporarily decreases.

  Further, although the permission point is set for detecting a steep density change, it may be determined whether or not the sampling period is shortened depending on whether or not the difference from the density at the previous sampling point is a predetermined value or more.

  Further, in the above-described embodiment, the sampling period at the beginning of startup is continuously timed even after the changed sampling period, and when the sampling period is returned, the gas is sampled at the sampling time immediately after the return. Concentration was measured, but when the sampling cycle was changed, the timing of the sampling cycle at the beginning of the startup was stopped, and when the sampling cycle returned, the timing of the sampling cycle at the beginning of the startup was started from that point. It may be. For example, in the case of FIG. 4, after changing to the sampling cycle of 10 seconds in 30 seconds from the start, when the alarm is issued in 40 seconds and the sampling cycle is returned, the next gas concentration is reached in 70 seconds after 40 seconds to 30 seconds. May be measured. That is, when the sampling time is changed, the measurement of the sampling time before the change may or may not be stopped.

  Further, the above-described embodiments are merely representative forms of the present invention, and the present invention is not limited to the embodiments. That is, various modifications can be made without departing from the scope of the present invention.

1 Gas sensor (gas detection means)
10 Microcomputer (gas concentration measurement means, control means)
30 Voice alarm output circuit (alarm means)

Claims (4)

A gas detection means for detecting a target gas in the atmosphere; a gas concentration measurement means for measuring the concentration of the gas detected by the gas detection means; a control means for causing the gas concentration measurement means to measure at a predetermined sampling period; and the gas In an alarm device comprising alarm means for outputting an alarm according to the concentration measured by the concentration measuring means,
If the control means detects that the concentration measured by the gas concentration measuring means is less than the concentration at which the alarm means outputs an alarm, and the concentration measured by the gas concentration measuring means has changed by more than a predetermined concentration at adjacent sampling points, the sampling is performed. An alarm device characterized by being changed so as to shorten the cycle.   A first determination point that is less than the concentration at which the warning means outputs an alarm to the control means; and a second determination point that is a concentration that is lower than the predetermined concentration change by a predetermined amount from the first determination point; Is set, and the control means detects that the sampling period has changed from a density lower than the second determination point to a density higher than the first determination point during one period. The alarm device according to claim 1, wherein the alarm device is changed so as to shorten.   The number of times of measurement in a short sampling period is predetermined in the control means, and the control means returns to the sampling period before changing to the shortened sampling period after the predetermined number of times measurement. The alarm device according to 1 or 2.   If the alarm means outputs an alarm when the control means is causing the gas concentration measuring means to measure the concentration at a shortened sampling period, the control means returns to the sampling period before the change to the shortened sampling period. The alarm device according to any one of claims 1 to 3.

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