JP3744261B2 - Fire detector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fire detector with a fire detection display function used for a fire alarm device.
[0002]
[Prior art]
FIG. 3 is a circuit diagram illustrating a conventional fire detector. As shown in FIG. 3, the fire detector 1 includes a sensor unit 2 and a signal processing unit 3. The sensor unit 2 is configured by connecting a thermistor 20 and a light emitting diode 21 corresponding to a fire display element in parallel. The cathode side of the light emitting diode 21 connected in parallel is connected to the connection terminal a, and the anode side of the light emitting diode 21 is connected to the anode side. Each is connected to a connection terminal b. The thermistor 20 changes to a resistance value corresponding to the ambient temperature. The light emitting diode 21 emits light by passing a current in the forward direction, although it does not pass a current in the reverse direction and is in a light-off state.
[0003]
The signal processing unit 3 includes a microcomputer 30, a polarity inverting circuit 31, a fire signal circuit 32, a resistor R ₀ that is a voltage dividing resistor and a current limiting resistor, a switch SW ₀ , a connection terminal A, and a connection terminal B. It is comprised including. The microcomputer 30 includes a first port P ₁ , a second port P _2, and a third port P _3, and an A / D conversion circuit 33 inside. The A / D conversion circuit 33 converts the analog voltage input to the second port P ₂ into a digital value and outputs the digital value to the fire signal circuit 32.
[0004]
Polarity inverting circuit 31 includes two common terminals C _1, C ₂ and four contacts _{D 1, D 2, D 3} , D 4, and the movable piece E ₁ to be connected to the common terminal C _1, the common terminal C _And a movable piece E ₂ connected to ₂ . The contact terminal D ₁ and the contact terminal D ₃ are connected to the connection terminal A, and the contact terminal D ₂ and the contact terminal D ₄ are connected to the connection terminal B. The common terminal C ₁ is connected to the second port P ₂ and is connected to the anode power source V _DD via the resistor R ₀ and the switch SW ₀ . The common terminal C ₂ is connected to ground. Further, the switch SW ₀ is controlled by the first port P ₁ , and the movable pieces E _{1 and} E ₂ are controlled by the third port P ₃ .
[0005]
The fire signal circuit 32 determines whether or not there is a fire based on the digital value from the A / D conversion circuit 33. When the fire signal circuit 32 determines that there is a fire, it outputs a fire signal to the fire receiver, The fact is output to the microcomputer 30. The connection terminal A is connected to the connection terminal a, and the connection terminal B is connected to the connection terminal b.
[0006]
The conventional fire detector 1 as described above operates as follows. That is, first, the fire detector 1 turns on the switch SW ₀ by setting the first port P ₁ of the microcomputer 30 to High and sets the common port C ₁ by setting the third port P ₃ to Low. It was connected to the contact D ₁ by the movable piece E _1, to connect the common terminal C ₂ to the contact D ₄ by the movable piece E _2. Then, the voltage of the anode power source V _DD is divided by the resistor R ₀ and the thermistor 20. The divided voltage is turned on the voltage value corresponding to the ambient temperature detected by the thermistor 20 is inputted to the A / D converter circuit 3 3 through the second port P _2, it is converted into a digital value . When the conversion to the digital value is completed, the fire detector 1 turns off the switch SW ₀ by setting the first port P ₁ of the microcomputer 30 to Low, and ends the ambient temperature measurement.
[0007]
The fire signal circuit 32 obtains the ambient temperature from the digital value obtained by the above procedure, and outputs the fire signal to the fire receiver if the temperature reaches a temperature at which it can be determined that the fire has occurred. Output. Then, the microcomputer 30 turns on the switch SW ₀ by setting the first port P ₁ of the microcomputer 30 to High, and sets the common port C ₁ to the movable piece E by setting the third port P ₃ to High. connected to the contacts D ₂ at _1, to connect the common terminal C ₂ to the contact D ₃ at the movable piece E _2.
[0008]
Then, the current from the anode power source V _DD is as follows: switch SW ₀ → resistance R ₀ → common terminal C ₁ → movable piece E ₁ → contact D ₂ → connection terminal B → connection terminal b → light emitting diode 21 and thermistor 20 → connection terminal. The light-emitting diode 21 is lit by flowing through the path a → connection terminal A → contact D ₃ → movable piece E ₂ → common terminal C ₂ → ground. Then, every time a predetermined time elapses, the first port P ₁ of the microcomputer 30 is changed from High → Low → High → Low... To turn on the switch SW ₀ , and the light emitting diode 21 blinks. .
[0009]
In other words, in the conventional fire detector 1, the fire detector 1 that has detected the fire is the fire detector 1 that has detected the fire, such as the fire detector 1 in which the light emitting diode 21 is blinking. It can be specified.
[0010]
[Problems to be solved by the invention]
However, the conventional fire detector as described above requires the polarity inversion circuit 31 and controls the polarity inversion circuit 31 in order to perform both the measurement of the ambient temperature and the blinking of the light emitting diode. The third port P ₃ of the microcomputer 30 is required. Therefore, there is a problem that the circuit configuration becomes complicated and the cost increases.
[0011]
The present invention has been made to solve such problems, and can measure both the ambient temperature and turn on the fire display element, and can be configured simply and inexpensively. To provide an excellent fire detector.
[0012]
[Means for Solving the Problems]
In the first aspect of the present invention, a sensor unit having a thermistor whose resistance value changes according to the ambient temperature, a fire indicator element connected thereto, and a voltage dividing resistor for the sensor unit, the ambient temperature based on the partial pressure value In a fire detector comprising a signal processing unit that measures fire and detects a fire, the signal processing unit applies a voltage to the sensor unit to obtain the partial pressure value, and the lighting of the fire display element is performed. After the signal processing unit has made a determination that a fire has occurred from the partial pressure value, the lighting time of the fire display element is visually recognized for the time to apply a voltage to the sensor unit. It is characterized in that it is made to be as long as possible.
[0013]
The invention according to claim 2 is characterized in that the fire display element is a bipolar display element.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the first embodiment of the fire detector according to the present invention will be described in detail with reference to FIG. 1, and the second embodiment will be described in detail with reference to FIG. 2.
[0015]
[First Embodiment]
FIG. 1 is a circuit diagram illustrating a fire detector. As shown in FIG. 1, the fire detector 1 includes a sensor unit 2 and a signal processing unit 3. The sensor unit 2 is configured by connecting a thermistor 20 and a light emitting diode 21 corresponding to a fire display element in series. The anode side of the serially connected light emitting diode 21 is connected to the connection terminal a, and the cathode side of the light emitting diode 21 is connected to the cathode side. Each is connected to a connection terminal b. The thermistor 20 changes to a resistance value corresponding to the ambient temperature. The light emitting diode 21 emits light by passing a current in the forward direction, although it does not pass a current in the reverse direction and is in a light-off state.
[0016]
The signal processing unit 3 is configured to include a microcomputer 30, a fire signal circuit 32, a resistor R ₀ is the partial pressure resistors and current limiting resistor, a switch SW _0, connected to the terminal A, and a connection terminal B . The microcomputer 30 includes a first port P ₁ and a second port P _2, and an A / D conversion circuit 33 inside. The A / D conversion circuit 33 converts the analog voltage input to the second port P ₂ into a digital value and outputs the digital value to the fire signal circuit 32.
[0017]
The connection terminal A is connected to the second port P ₂ and is connected to the anode power source V _DD via the resistor R ₀ and the switch SW ₀ . Connection terminal B is connected to ground. The switch SW ₀ is controlled by the first port P ₁ .
[0018]
The fire signal circuit 32 determines whether or not there is a fire based on the digital value from the A / D conversion circuit 33. When the fire signal circuit 32 determines that there is a fire, it outputs a fire signal to the fire receiver, The fact is output to the microcomputer 30. Then, the microcomputer 30 is configured to turn on the switch SW ₀ by setting the first port P ₁ of the microcomputer 30 to High. The connection terminal A is connected to the connection terminal a, and the connection terminal B is connected to the connection terminal b.
[0019]
The fire detector 1 as described above operates as follows. That is, first, the fire detector 1 turns on the switch SW ₀ by setting the first port P ₁ of the microcomputer 30 to High. Then, the voltage of the anode power source V _DD is substantially divided by the resistor R ₀ and the thermistor 20. In this case, since a forward voltage is applied to the light emitting diode 21, the voltage applied to the light emitting diode 21 can be regarded as a substantially constant value .
[0020]
The divided voltage is turned on the voltage value corresponding to the ambient temperature detected by the thermistor 20 is inputted to the A / D converter circuit 3 3 through the second port P _2, it is converted into a digital value . When the conversion to the digital value is completed, the fire detector 1 turns off the switch SW ₀ by setting the first port P ₁ of the microcomputer 30 to Low, and ends the ambient temperature measurement.
[0021]
Moreover, this is an important point of the present invention, but it starts from turning on the switch SW ₀ by setting the first port P ₁ of the microcomputer 30 to High, and then via the second port P _2. converting the divided voltage input to the a / D converter circuit 3 3 into a digital value, and ends the conversion to a digital value, the switch SW by the first port P ₁ of the microcomputer 30 to the Low A series of operations until ₀ is turned off is performed at a speed at which the light emission of the light emitting diode 21 is beyond the human eye.
[0022]
The fire signal circuit 32 obtains the ambient temperature from the digital value obtained by the above procedure, and outputs the fire signal to the fire receiver if the temperature reaches a temperature at which it can be determined that the fire has occurred. Output. Then, the microcomputer 30 turns on the switch SW ₀ by setting the first port P ₁ of the microcomputer 30 to High.
[0023]
Then, the current from the anode power source V _DD flows through the path of switch SW ₀ → resistance R ₀ → connection terminal A → connection terminal a → thermistor 20 → light emitting diode 21 → connection terminal b → connection terminal B → ground, and the light emitting diode 21 lights up. Then, a predetermined time every elapse, the switch SW ₀ ON → OFF → ON → OFF ... brought by the first port P ₁ of the microcomputer 30 is High → Low → High → Low ..., performs blinking light-emitting diode 21 . That is, even in this fire detector 1, as in the case of the conventional fire detector, the fire detector 1 in which the light emitting diode 21 is blinking is the fire detector 1 that has detected a fire. The detected fire detector 1 can be specified.
[0024]
[Second Embodiment]
FIG. 2 is a circuit diagram illustrating the fire detector. As shown in FIG. 2, the fire detector 1 is different from the fire detector of the first embodiment in that a light emitting diode 21 as a fire display element is a bipolar display element corresponding to a bipolar display element. The light emitting diode 22 is configured.
[0025]
In other words, in the fire detector of the first embodiment, the anode side of the light emitting diode 21 must be connected to the connection terminal A. If the connection is incorrect, the temperature of the light emitting diode can be measured as well as the temperature measurement. Although it cannot be lit, the fire detector 1 of the second embodiment shown in FIG. 2 employs the bipolar light emitting diode 22 so that the polarity is lost, and troubles due to incorrect connection can be eliminated. . In particular, in a fire detector in which the sensor unit 2 and the signal processing unit 3 are separated and the sensor unit 2 and the signal processing unit 3 are connected at the time of construction on site, Troubles due to incorrect connection due to carelessness can be eliminated.
[0026]
【The invention's effect】
Since the fire detector of the present invention is configured as described above, in the invention according to claim 1, the circuit configuration is simple and inexpensive, and the ambient temperature is measured and the fire display element is turned on. It is possible to provide a fire detector that is superior and can be performed together.
[0027]
In the invention according to claim 2, in addition to the effect of the invention according to claim 1, in the fire detector in which the sensor part and the signal processing part are separated, in particular, carelessness of the construction worker. There is an effect that it is possible to provide an excellent fire detector that can eliminate troubles caused by incorrect connection.
[Brief description of the drawings]
FIG. 1 is a circuit diagram illustrating a fire detector according to a first embodiment of the present invention.
FIG. 2 is a circuit diagram illustrating a fire detector according to a second embodiment of the present invention.
FIG. 3 is a circuit diagram illustrating a conventional fire detector.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fire detector 2 Sensor part 20 Thermistor 21 Fire display element 22 Bipolar display element 3 Signal processing part R ₀ Voltage dividing resistance

Claims (2)

A sensor unit with a fire display element connected to a thermistor whose resistance value changes according to the ambient temperature, and a signal processing unit that has a resistance to the sensor unit and measures the ambient temperature based on the partial pressure value to detect fire In a fire detector comprising:
The time for which the signal processing unit applies a voltage to the sensor unit to obtain the partial pressure value is shortened so that the lighting of the fire display element is not visually recognized, and the signal processing unit fires from the partial pressure value. After making the determination that it is, the fire detector is characterized in that the time for applying the voltage to the sensor unit is extended to such an extent that the lighting of the fire display element is visually recognized. The fire detector according to claim 1, wherein the fire display element is a bipolar display element.

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