JPH0236034B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a fire detection system in which detection information from detection units with different detection mechanisms is received by a receiver, and a fire judgment is made according to the type of detection unit. Regarding alarm devices.

(Prior Art) Conventionally, in so-called analog fire alarm systems, a detector detects changes in physical phenomena associated with a fire, such as temperature and smoke concentration, in an analog manner, and a receiver determines whether there is a fire. In order to quickly and accurately determine a fire, we use detectors with different detection mechanisms, such as ionization smoke detectors, photoelectric smoke detectors, temperature detectors,
It is being considered to connect a CO gas detector, humidity detector, etc.

In this way, when multiple types of detectors with different detection mechanisms are connected by signal lines, the threshold level for determining fire is different depending on the type of detector, and therefore the receiver uses the detection information in addition to the detection information. Type information indicating the type of vessel was required.

As a conventional method for transmitting this type information to a receiver, for example, a method is known in which one or more bits in a signal code of detection information sent back to the receiver are assigned to type bits representing the type.

However, when type bits are assigned to the code bits of the returned signal, the number of type bits increases as the type of detector increases, and the number of bits of the signal code transmitted between the receiver and the terminal increases. Since there is a limit to the number, the number of signal bits of the detection information decreases as the number of type bits increases, resulting in a problem in that the resolution of the detection information sent back to the receiver decreases.

(Object of the Invention) The present invention has been made in view of these conventional problems, and it is possible to transmit detector type information to a receiver without affecting the number of signal bits of detection information. The purpose is to provide a fire alarm system.

(Structure and operation of the invention) In order to achieve this object, the present invention is based on temporally separating transmission of type information and transmission of detection information, and specifically, calls for type information from a receiver. The terminal device returns type information according to the specified level that differs depending on the type of detector, the receiver performs type discrimination, and after this type discrimination, the process moves to calling the detection information, and the received detection information is used to retrieve the detection information in advance. Fires are determined based on the results of the type discrimination being carried out.

With this configuration, all bits of the transmission code between the receiver and the terminal device can be used for detection information, and even if the types of detectors increase, the accuracy of detection information for the receiver does not decrease. This allows accurate and quick fire judgment.

(Embodiment) FIG. 1 is a circuit block diagram showing the basic configuration of the present invention, which uses a three-wire system.

First, to explain the configuration, 1 is a receiver, and a power supply line 2, a signal line 3, and a common line 4 are drawn out from the receiver 1, and terminal devices 5a, 5b, 5c...5n are connected to these three signal lines. are connected in parallel. Each of the terminal devices 5a to 5n is connected to a detection section that detects changes in physical phenomena caused by a fire by a signal line, and the detection section is provided with a different detection mechanism for each terminal device.

That is, an ionization type smoke detector 6 that detects smoke concentration is connected to the terminal device 5a, a photoelectric type smoke detector 7 that also detects smoke concentration is connected to the terminal device 5b, and a terminal device 5c is connected to the terminal device 5c. A heat sensor 8 for detecting temperature rise is connected, and a terminal 5n is also connected.
A gas detector 9 for detecting CO gas is connected.
Of course, the detection units connected to the terminals 5a to 5n are not limited to these, and appropriate detection units having other detection mechanisms can be connected. Also,
Each of the ionization smoke detectors 6, photoelectric smoke detectors 7, heat detectors 8, and gas detectors 9 connected to the terminals 5a to 5n outputs analog detection signals that change according to smoke concentration, temperature, and gas concentration. Output.

FIG. 2a is a circuit diagram representing one embodiment of the terminal device in the embodiment of FIG. 1, illustrating the terminal device 5a to which the ionization type smoke detector 6 is connected.

The terminal device 5a has terminals A, B, and C and is connected to the receiver 1.
power supply line 2, signal line 3 and common line 4
A constant voltage circuit 10 supplies a constant voltage to each circuit section of the terminal.

Reference numeral 11 denotes a signal processing unit, which receives a command pulse consisting of an address code and an information code following the address code given from the receiver 1 via the signal line 3, and determines whether it is calling itself and also outputs a set signal for the type of call. It has a function of decoding and outputting the detection information, and returning the detection information of the ionization type smoke detector 6 as a digital signal for calling up the detection information. That is, the signal processing section 11 includes a transmitting/receiving section 11a and a terminal control section 11b, as shown in FIG.
and an address setting section 11c. 12 is an A/D conversion circuit which converts the type signal obtained when receiving a type call or the detection signal of the ionization smoke detector 6 into a 4-bit digital signal consisting of a ₀ , a ₁ , a ₂ , and a ₃ . The signal is converted into a signal and output to the signal processing section 11.

On the other hand, the ionization type smoke detector 6 has an external electrode 1 that forms an external chamber into which smoke flows from the outside.
3. Intermediate electrode 14, internal electrode 14 forming an internal chamber from which outside air is blocked, internal electrode 1
The radiation source 16 ionizes the air in the inner and outer chambers, and when smoke flows into the outer chamber from the outer electrode 13, a radiation source 16 is installed in the outer chamber. This causes a change in the voltage between the electrodes. The output of this ionization type smoke detector 6, that is, the intermediate electrode 14 is FET1
7, and the voltage V3 of the source S changes depending on the smoke density. The source S of the FET 17 is connected to the minus input terminal of the operational amplifier 18 via a resistor R2, and the set voltage V2 from the variable resistor VR1 is applied to the plus input terminal via a resistor R3. Furthermore, the operational amplifier 18 is equipped with a feedback resistor R1, and if the source output voltage of the FET 17 is V3 and the output voltage of the operational amplifier 18 is Vo, then Vo=(V2−V3)・(R1/R2)……(1) The output voltage Vo given by A/D is amplified and output.
It is input to the conversion circuit 12.

In the detection circuit of such an ionization type smoke detector 6, a series circuit consisting of a transistor 19 and a Zener diode ZD is further connected in parallel with the load resistance Ro of the FET 17, and the base of the transistor 19 is connected to the type call from the signal processing section 1. The set signal obtained in
is turned on, and the input voltage V3 to the operational amplifier 18 is
This constitutes a prescribed level setting means for setting the voltage to a prescribed level determined by the Zener diode ZD. Here, the input voltage V3 of the operational amplifier 18, which is determined when the transistor 19 is turned on by the set signal corresponding to the type call, is defined as Vi, which is the voltage across the load resistor Ro when the transistor 19 is turned on.
Input voltage V3 is given by V3 = Vc - Vi. When the transistor 19 is turned on by the set signal in this way, the Zener diode ZD
The zener voltage of the zener diode ZD is selected so that the input voltage V3 determined by the zener voltage is Vc>V2≧V3. For example input voltage
Select the zener voltage that gives Vi such that V3 becomes V3=Vc/2.

Here, in normal times when there is no smoke flowing into the ionization type smoke detector 6, the output voltage of the operational amplifier 18 is
Since Vo is zero volts, the output Vo of the operational amplifier 18 in the normal state, Vo = 0 volts, is used as the signal level of the type signal in response to the type call from the receiver. In order to send back such a type signal, it is sufficient to adjust the set voltage V2 by the variable resistor VR1 to be equal to the input voltage V3 when the transistor 19 is turned on, and by setting V2 = V3, the above-mentioned From equation (1), the output voltage Vo output from the operational amplifier 18 when a type call is received can be set to the normal state detection level where Vo=0 volts, that is, the base level. Of course, the output level when receiving a type call may be set to any signal level other than the base level of Vo=0 volts.

In this way, in the case of the terminal device 5a connected to the ionization type smoke detector 6 shown in FIG. set to the corresponding base level. On the other hand, in the case of other terminal devices 5b to 5n to which the photoelectric smoke detector 7, heat sensor 8, and gas detector 9 are connected, the basis of the detection signal in the normal state is different from that of the ionization smoke detector 6. Since the terminal has a level, the values of the Zener diode ZD and the variable resistor VR1 in the terminal device are determined so that the base level unique to each detection section is set when a type call is received. That is, if the base level of the ionization smoke detector 6 is Vo1, the base level of the photoelectric smoke detector 7 is Vo2, the base level of the heat sensor is Vo3, and the base level of the gas sensor 9 is Von, then these base levels are Between the levels, Vo1≠Vo2≠Vo3≠Von is set, and when a type call is received, a type signal corresponding to each base level is output.

FIG. 3 is a block diagram showing the configuration of receiver 1 in FIG. 1.

In FIG. 3a, 20 is a control unit which commands a type call immediately after the power is turned on, and after the type call is finished, performs a return call for detection information;
1 sequentially outputs a control signal from the control unit 20, that is, a signal code corresponding to a type call or a return call for detection information, to the signal line 3 as a command pulse together with the address code of the terminals 5a to 5n. A signal processing section 22 determines whether the type information or detection information returned from the terminal device is received for each address of the terminal device. A type discrimination unit that discriminates the type, 23 is a signal processing unit 21
A calculation processing unit 24 converts the detection information received by the calculation processing unit 23 into data based on the type information from the type discrimination unit 22 and calculates a threshold level for determining a fire from the type information. A fire discrimination section 25 determines a fire by comparing the detection information with a threshold level, and 25 is an alarm display section 26 that issues a fire alarm based on the discrimination output of the fire discrimination section 24 and displays the fire area according to the terminal address.
is a constant voltage power supply that supplies power to the terminal device.

As shown in FIG. 3b, the signal processing section 21 is comprised of an address generation section 21a, a signal code generation section 21b, a transmission section 21c, a reception section 21d, and an address/code discrimination section 21e. Further, as shown in FIG. 3c, the arithmetic processing section 23 is composed of a data conversion section 23a and a threshold value calculation section 23b.

The receiver 1 having such a circuit configuration can be realized by program control of a microcomputer.

Next, the operation of the above embodiment will be explained with reference to the timing chart of FIG.

When the receiver 1 side is powered on, the control section 20 of the receiver 1 shown in FIG. 3 first instructs the signal processing section 21 to call the type. In response to this type call command, the signal processing section 21 sequentially outputs a type call command pulse consisting of an address code and a set signal to each of the terminals 5a to 5n. This type call pulse is sent in a voltage mode that causes the signal line 3 to vary between _VH and _VL .

The type call command pulse output from the receiver 1 is received by each of the terminals 5a to 5n, and since the first type call pulse has the address code of the terminal 5a, the terminal shown in FIG. The signal processing section 11 of the device 5a determines whether it is calling itself, decodes the set signal following the address code, outputs the set signal to the transistor 19, and turns it on. When the transistor 19 turns on, the Zener diode ZD becomes conductive, and the input voltage V3 of the operational amplifier 18
is given as V3=Vc−Vi. Here, V2
= V3, the output voltage Vo of the operational amplifier 18 becomes Vo=0 volts, and the signal processing unit 11 receives (a ₀ , a ₁ , a ₂ , a ₃ ) = (0000) from the A/D conversion circuit 12. The signal processing unit 11 uses the idle time of the type call pulse from the receiver to send the type data together with the address code back to the receiver 1 in the same voltage mode.

In the receiver 1, as shown in FIG. 3, the signal processing section 21 receives the address and type data returned from the terminal device 5a, and the type discrimination section 22 receives the ionized data from the received type data. It is determined that the type smoke detector 6 is connected, and type information is provided to the calculation processing unit 23 as basic data for calculation.

Such type calling is performed in the same manner for the terminals 5b to 5n.

When the type check of the detection units connected to all the terminals 5a to 5n is completed, the control unit 20 of the receiver 1
commands the signal processing unit 21 to call back the detection information, and the signal processing unit 21 sends the address code to the terminals 5a to 5n in order to make the call, and in response to this call, the terminals send back the detection information to each detection unit. Receiver 1 sends the detection information detected by receiver 1 along with the address code.
In the receiver 1, the signal processing unit 21 receives the returned information and provides it to the arithmetic processing unit 23, which reproduces the detection information based on the type information and calculates the threshold level based on the type information, and fire detection is performed. When the detected information exceeds the threshold level by comparison calculation in section 24, a fire discrimination output is output, and alarm display section 25 displays a fire alarm along with display of the area where the fire occurred based on the address information.

In addition, in the pulse signal used for the return call of detection information, the part of the set signal that follows the address code used for the type call is an empty code, but this empty code part can be used if the terminal is equipped with a control load. It can be used as a control bit to command the operation of a control load.

In this way, in the above embodiment, the type of the detection unit connected to the terminal is checked immediately after power is turned on, and the detection information is returned after checking the type, so that the data bits from the terminal are It is no longer necessary to provide a dedicated type bit to represent the type, and the resolution of the detected information can be maintained even when the type is checked. Also,
Even if the number of detection units increases, all data bits can be used to transmit type information, so for example, if there are 4 bits, 16 types of type information can be transmitted to the receiver without reducing the resolution of the detected information. Obtainable.

FIG. 5 is a block diagram showing another embodiment of the present invention, and this embodiment is characterized in that the signal line connection between the receiver and the terminal is a two-wire system.

First, to explain the configuration, 30 is a receiver;
A power signal line 31 and a common line 32 are led out from the receiver 30, and a plurality of terminal devices 33a, 33b, 33c,
...33n is connected, and the terminals 33a to 33n have an ionization smoke detector 6, a photoelectric smoke detector 7, and a heat detector 8 as detection units having different detection mechanisms.
and a gas detector 9 are connected.

FIG. 6a is a circuit block diagram showing an embodiment of the terminal device in FIG. 34 supplies a constant voltage to the terminal circuit section. 35 is a signal processing unit which receives a command pulse for type calling or a command pulse for returning detection information from the receiver 30, determines its own call from the address code included in the command pulse, and also follows the address code. A set signal is output to the transistor 40 in order to cut off the output of the detection section 36 when decoding the set signal and returning the type information. This signal processing section 35, as shown in FIG. 6b,
It is composed of a transmitting/receiving section 35a, a terminal control section 35b, and an address setting section 35c. 36 is a detection unit, which includes the ionization smoke detector 6, photoelectric smoke detector 7, heat sensor 8, or gas detector 9 shown in FIG.
is used to output detection outputs in analog form according to each detection mechanism. 37 is an operational amplifier, which inputs the detection signal of the detection section 36 via a resistor R4;
The impedance-converted output is supplied to the base of the transistor 38 via the resistor R5, and a line current Is corresponding to the detected output is caused to flow through the power supply signal line 31. A resistor R6 and a transistor 39 are connected in series to the emitter side of the transistor 38.
The output of the signal processing unit 35 is applied to the base of the transistor 39 via a resistor R7, and the transistor 39 receives the idle time until the next command pulse is output every time the signal processing unit 35 determines its own call. The line is turned on to allow return line current to flow throughout the period. In addition, a variable resistor VR2 is connected in parallel to the series circuit of the transistor 38 and the resistor R6.
A base current is set by VR2, and when a type call is received, a different type current Io is caused to flow through the power supply signal line 31 for each type of detection section.

On the other hand, the input of the operational amplifier 37 is connected to the detection section 36.
A transistor 40 is provided to cut off the output of the transistor 40, and the output of the signal processing section 35 is applied to the base of the transistor 40 via a resistor R8. The input of the operational amplifier 37 is forcibly cut off, and by turning off the transistor 38, only the type current Io determined by the resistor VR2 is allowed to flow through the power supply signal line 31.

FIG. 7a is a circuit block diagram showing an embodiment of the receiver 30 in FIG. 5, where 41 is a control unit for calling the type and calling back the detection information, and 42 is the control unit for calling the type or calling back the detected information. This is a signal processing unit that sends out a command pulse according to the voltage as a voltage pulse superimposed on the power supply voltage from the constant voltage power supply 48, and receives and outputs a return signal sent back from the terminal device in current mode. This signal processing section 42 is shown in FIG.
As shown in FIG. 2, a pulse/voltage conversion section 42a is provided which converts a command pulse corresponding to a type call or a detection information return call from the control section 41 into a voltage pulse superimposed on the power supply voltage. 43 is an A/D conversion circuit that converts the return current from the terminal device inputted through the signal processing unit 42 into a voltage signal using a resistor R10 and then converts it into a digital signal; 44 is the type converted by the A/D conversion circuit 43; A type discrimination section 45 discriminates the type of the detection section connected to the terminal device from the digital current signal, and 45 is an arithmetic processing section that reproduces detection information based on the type information and calculates a threshold level. Reference numeral 45 has the same configuration as the arithmetic processing section 23 shown in FIG. 3c. 4
Reference numeral 6 denotes a fire discrimination unit that determines a fire by comparing detection information and a threshold level, and reference numeral 47 denotes an alarm display unit that displays a fire alarm display for each district determined by the terminal address based on the fire discrimination output.

Next, the operation will be explained with reference to the time chart shown in FIG.

First, the terminal device 3 having the circuit configuration shown in FIG.
In each of 3a to 33n, response currents Io ₁ to Ion for the type call shown in FIG. 9, for example, are set depending on the type of detection section connected to the signal line.

That is, if the signal bits used for digital arithmetic processing in the receiver 30 are 4 bits, the return current sent back to the receiver is divided into 16 stages from I _L to I _H shown in FIG. For example, the type current Io ₁ of the ionization type smoke detector 6 is set to 1 level, and the type current Io of the photoelectric smoke detector 7 is set in stages for the return current.
The type current Io ₂ of the heat sensor has three stages, and the type current Io ₃ of the heat sensor
The variable resistor VR2 in FIG. 6 is set so that the type current Ion of the gas detector 9 has two stages.

Therefore, when the receiver 30 is powered on as shown in the timing chart of FIG.
first instructs the signal processing unit 42 to send out a command pulse for type calling, superimposes it on the power supply voltage determined by the constant voltage power supply 48, and sends the command pulse varying from V _L to V _H to the terminals 33a to 33n in voltage mode. Output to each. This type calling command pulse consists of an address code and a set signal, and is composed of an address code and a set signal.
33n turns on the transistor 39 at the timing of the idle time of the command pulse when it determines its own call, and also turns on the transistor 40 when decoding the set signal due to the type call to cut off the detection output of the detection section 36. Therefore, as the output of the operational amplifier 37 disappears, the transistor 38 also turns off, and the type current Io determined by the variable resistor VR2 flows through the transistor 39 to the power supply signal line 31.

The type current generated by this terminal device appears as a voltage change in the resistor R10 via the signal processing section 42 of the receiver 30, is converted into a digital signal by the A/D conversion circuit 43, and is converted into a digital signal by the type discrimination section 44 according to the type current Io. The type of the detected unit is determined.

The type check in response to the command pulse for type calling is performed in the order of the terminals 33a to 33n, and when all type checks are completed, the control unit 41 of the receiver 30 sends back the detection information to the signal processing unit 42. The signal processing unit 42 sequentially outputs command pulses including address codes without a set signal. The signal processing unit 35 of the terminal that received this detection information return call command pulse
The transistor 39 is turned on at the timing of the idle time of the command pulse, and since the set signal is not obtained at this time, the transistor 40 is off, and the detected current is caused by the conduction of the transistor 38 according to the detection output of the detection section 36. Is is superimposed on the type current Io determined by the variable resistor VR2, and a line current of (Is+Io) is caused to flow through the power signal line 31.

The line current (Is + Io) returned from the terminal device is converted into a digital signal by the A/D conversion circuit 43 of the receiver 30, and the detected information is reproduced by removing the type current Io included in the received current in the arithmetic processing unit 45. However, at the same time, a threshold level is calculated based on the type information, and the presence or absence of a fire is determined from the received detection information through a comparison calculation by the fire determining section 46.

In addition, in this embodiment as well, the terminal devices 33a to 33
The type current set by the variable resistor VR2 of n may be set to a current value (base current level) according to the detection output in the normal state of the detection section in each terminal, and it naturally depends on the type of the detection section. Set different types of current accordingly.

(Effects of the Invention) As described above, according to the present invention, there are multiple types of detection units with different fire detection mechanisms, a terminal device provided for each detection unit, and detection information from each terminal device. In a fire alarm system consisting of a receiver that receives fire alarms and determines whether there is a fire, the type check of the detection unit and the return of detection information are separated in time, so the type is included in the signal bit of the detection information. Since it is no longer necessary to include a type bit representing the detection unit, and the number of signal bits of the detection information is not affected even if the detection unit type is checked, the resolution of the detection information can be maintained at the resolution determined by the number of signal bits. Can be done.

In addition, since the number of types of detection units can be increased without affecting the resolution of detected information, fires can be comprehensively judged from the detection information of multiple detection units with different detection mechanisms, allowing quick and accurate detection of fires. enable judgment. Furthermore, in the present invention, table information indicating the correspondence between sensor addresses and types is automatically created at the initial setting stage before the power is turned on and alarm monitoring is started. Compared to a method that sets a correspondence table between sensor addresses and types, there is no need to modify the table on the receiver side even if specifications change at the site.
Easily responds to changes in on-site specifications.

Furthermore, if the specified level of the detection section indicating the type signal is set as the base level (so-called zero point level) as the detection level of the detection section during normal times, the base level is different for each type of detection section, so it is easy to It is possible to set a specified level to indicate the type signal.

[Brief explanation of drawings]

Fig. 1 is a circuit block diagram showing an embodiment of the present invention, Fig. 2 is a circuit block diagram showing an embodiment of the terminal device shown in Fig. 1, and Fig. 3 is an embodiment of the receiver shown in Fig. 1. FIG. 4 is a timing chart showing the operation of the embodiment shown in FIG. 1, and FIG.
6 is a circuit diagram showing another embodiment of the present invention, FIG. 6 is a circuit diagram showing an embodiment of the terminal device shown in FIG. 5, and FIG. 7 is a circuit diagram showing an embodiment of the receiver shown in FIG. 5. 8 is a timing chart showing the operation of the embodiment of FIG. 5, and FIG. 9 is an explanatory diagram showing the type current level set in the terminal device in the embodiment of FIG. 5. 1, 30: Receiver, 2: Power supply line, 3: Signal line, 4, 32: Common line, 5a~5n, 33a~
33n: Terminal, 6: Ionization smoke detector, 7:
Photoelectric smoke detector, 8: Heat sensor, 9: Gas detector, 10, 34: Constant voltage circuit, 11, 35: Signal processing unit, 12, 43: A/D conversion circuit, 17:
FET, 18, 37: Operational amplifier, 19, 38,
39, 40: Transistor, 20, 41: Control unit, 21, 42: Signal processing unit, 22, 44: Type discrimination unit, 23, 45: Arithmetic processing unit, 24, 46:
Fire discrimination section, 25, 47: Alarm display section, 26, 4
8: Constant voltage power supply, 31: Power supply/signal line.

Claims (1)

[Scope of Claims] 1 A system comprising multiple types of detection units with different fire detection mechanisms, a terminal device provided for each detection unit, and a receiver that receives detection information from each terminal device and determines whether there is a fire. In the fire alarm system, each of the terminals includes a prescribed level setting means that is activated by a type call from the receiver and sets the output of the detection section to a prescribed level that is different for each type of detection section; return means for transmitting the output of the detection unit set to a prescribed level by the level setting means to a receiver as a type signal; a type determining means for receiving a type signal from the terminal and determining the type of a detection unit connected to the terminal; a detection information calling means for instructing the terminal to return detection information after determining the type; 1. A fire alarm device comprising: fire determining means for receiving detection information from a terminal device and determining fire based on type information from the type determining section. 2. The device according to claim 1, wherein the predetermined level setting means of the terminal device sets the predetermined level to a base level that is a detection output in a normal state that differs depending on the type of detector. Fire alarm system.