JPH0335718B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, when receiving an alarm from a fire detection terminal installed in a restricted area, the receiver starts scanning the terminal, and the terminal that issued the alarm is called. The present invention relates to a fire alarm system that transmits and displays temporal changes in physical phenomena due to fire detected by the sensor section of the terminal device and the address of the terminal device to a receiver.

Conventionally, fire alarm equipment that sends temporal changes in smoke concentration, temperature, etc. caused by a fire detected by a fire sensor to a receiver in multiple detection stages has, for example, a pair of sensors pulled out from a receiver. A plurality of terminal devices having a fire sensor section are connected in parallel between the power supply and signal lines of the receiver, and a paging scan is performed in which the receiver periodically calls the plurality of terminal devices in sequence, and the terminal device that detects a fire is called. Then, data corresponding to the detection stage of the fire sensor unit is sent to the receiver, and the receiver side decodes the address of the terminal device that sent the data by counting the calling signal, etc., and determines the fire stage based on the data reception. The address of the terminal device is displayed (Japanese Patent Laid-Open No. 53-60468)
issue).

In addition, as another conventional device, each of the power line and control line is individually drawn out from the receiver to the terminal.
Similarly, using a control line, a receiver cyclically calls multiple terminals in sequence with coded signals, and when a terminal that detects a fire is called, it sends data indicating the stage of the fire to the receiver, and the terminal It has been proposed to display the device address together with the device address (Japanese Patent Application Laid-Open No.
-47799).

However, all fire alarm systems use a method that constantly calls out a terminal device cyclically, and the frequency of fire occurrences is extremely low.
Continuing to cyclically monitor the terminal device in a steady monitoring state means that the receiver and the calling circuit section of the terminal device are constantly in operation, increasing current consumption and accelerating the deterioration of circuit elements that are always in operation. It could not be said to be an effective means of monitoring.

Furthermore, in the case of fire alarm equipment, multiple terminal devices are connected to a pair of signal lines, and even if any terminal device issues an alarm and data signals are being sent and received between the terminal device and the receiver, the corresponding The fire sensor section of not only the alarm terminal but also all other terminals must always receive normal monitoring voltage and continue monitoring, but in the case of the conventional method, these terminals The means for continuing to maintain the monitoring state were not disclosed.

The present invention has been made in view of these conventional problems, and detects changes in the surrounding physical phenomena caused by fire in multiple stages between a pair of power supply and signal lines drawn out from the receiver. A fire alarm system in which a plurality of terminal devices each having a sensor section that outputs a signal are connected in parallel, and the terminal device sends fire detection information based on the detection signal of the sensor section and address information of the terminal device as a data signal to a receiver. In the steady monitoring state, the receiver stops calling and scanning, and the receiver stops cycling only when it receives an alarm signal that is sent when a fire is detected by the sensor section of the terminal. The terminal device starts paging scanning, and when the terminal device that sent the alarm signal is called, the receiver stops paging scanning, and in this stopped state, fire detection information and address information set for the terminal device are sent from the terminal device. By sending a data signal consisting of In addition to reducing
Even if any terminal device issues an alarm and data signals are being sent and received between the terminal device and the receiver, the fire sensor sections of not only the alarming terminal device but also all other terminal devices will always be monitored normally. The purpose is to provide highly reliable fire alarm equipment that can receive voltage and continue monitoring.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 is a block diagram showing the basic configuration of the present invention.

First, to explain the configuration, 1 is a fire receiver, and from the fire receiver 1, a pair of power signal lines consisting of a combination of lines L ₁ , L ₂ . . . Ln and a common line C are connected to multiple warning areas. As represented by line _L1 , there is a sensor section 2a between line _L1 and common line C that outputs detection signals in multiple stages according to changes in surrounding physical phenomena caused by fire. ,2b,
...2n are connected in parallel, and these sensor parts 2a, 2n are connected in parallel.
b,...2a are combined with terminal devices 3a, 3b,...
3n are connected in parallel, and further line L ₁
and a terminating resistor 4 for detecting disconnection at the end of the common line C.
is connected.

Sensor unit 2a that outputs multi-stage fire detection signals
For example, in the case of detecting smoke from a fire, ~2n is set to type 1, type 2, and type 3 detection sensitivities that are set for ordinary smoke detectors, and the detection sensitivity increases depending on the increase in smoke concentration. The sensor is configured to output a detection signal of type 1 sensitivity, a detection signal of type 2 sensitivity, and a detection signal of type 3 sensitivity in multiple stages.

FIG. 2 shows the terminal device 3a in the embodiment of FIG.
FIG. 3 is a circuit block diagram showing a specific configuration of the circuits 3n and 3n together with a sensor section.

First, to explain the configuration, the terminal device 3 is connected between the line Ln and the common line C via the diode bridge 5, and the voltage obtained via the diode bridge 5 is supplied to each circuit section from the constant voltage circuit 6. It is supplied as voltage.

The first part of the sensor section 2 has one to three types of detection sensitivities.
The detection output of each stage, that is, the detection output of type 1 sensitivity, which has the highest detection sensitivity, is given to the alarm signal output circuit 7 via the monostable multivibrator 14c. In response to the signal, the line Ln and the common line C are short-circuited via the diode bridge 5 by the first impedance for the operating time of the monostable multivibrator 14c, for example, 100 msec, and an alarm signal is sent to the receiver.

The current I ₁ flowing through the line Ln due to the alarm signal sent by the first impedance of the alarm signal output circuit 7 is, for example, I ₁ =20 mA.

The value of current I ₁ due to sending out this alarm signal is line Ln
The current value is set at a value that is greater than or equal to the total amount of current consumed by multiple terminals connected to the terminal in a steady monitoring state.

On the other hand, a ringing signal detection circuit 8 is provided to detect a ringing pulse signal sent from the receiver to ring the terminal, and this ringing signal detection circuit 8 detects a voltage of 20V on the line Ln by the ringing pulse from the receiver.
Since the signal is a pulse signal that changes within the range of 30V and 30V, the calling signal is detected and output based on a voltage change of the line Ln that is, for example, about 7V or more.

Also, in order to prevent false detection due to superimposed noise, etc., the line Ln is designed to prevent erroneous detection due to superimposed noise, etc. For example, if the calling pulse signal from the receiver is a pulse signal with a pulse width of 10 mSec and a duty ratio of 50% and 20 mSec per cycle, 5 mSec. The configuration is such that only signals having the above pulse width are detected as a calling pulse signal.

A ringing pulse signal from the receiver detected by the ringing signal detection circuit 8 is given to a reset release circuit 10 and a counter circuit 11 via a pulse delay circuit 9. The counter circuit 11 and the decoder circuit 16 are activated by the detected first calling pulse to release the reset state, and therefore the counter circuit 11 starts counting operation from the second calling pulse signal detected by the calling signal detection circuit 8. It becomes like this.

The counter circuit 11 sequentially outputs the count value of the calling pulse signal to the address setting circuit 12, and the coincidence circuit 13 compares the address code of the terminal device 3 preset in the address setting circuit 12 with the count value of the counter circuit 11. , when both match, sensor unit 2
A coincidence output is generated on the condition that a detection signal is output from the detection signal.

The output of the matching circuit 13 is given to each of the monostable multivibrators 14a and 14b, and the monostable multivibrator 14a generates an output and operates the switch circuit 17 to send the constant voltage circuit 6 to the A/D conversion circuit 18. supplying a power supply voltage to bring it into an operating state, converting the detection signal from the sensor unit 2 according to the detection sensitivity into a digital signal and outputting it, and at the same time outputting the monostable multivibrator 14b to activate the oscillation circuit 15, The oscillation pulse of the oscillation circuit 15 is output to the decoder circuit 16. The decoder circuit 16 generates a pulse output that is sequentially shifted to the output terminal in synchronization with the oscillation pulse of the oscillation circuit 15, and starts the first terminal output via the OR circuit 19 in synchronization with the oscillation pulse by the AND gate 20. Data signal output circuit 21 as a signal
Then, the conversion output of the AD conversion circuit 18 to the AND gates 22a to 22n, that is, the fire data corresponding to the detection signal of the sensor unit 2 is sent out as fire detection information via the OR circuit 19 and the AND gate 20, Furthermore, the address code preset for the terminal device 3 in the data setting circuit 22 is outputted via the OR circuit 19 and the AND gate 20, and the final terminal output of the decoder circuit 16 is output as an end pulse to the OR circuit 19 and the AND gate. 2
Output from 0.

In this way, the shift output of the decoder circuit 16 generates a pulse train consisting of the start pulse fire detection information, address code, and end pulse, which is sent to the receiver by short-circuiting the line Ln with the second impedance corresponding to the pulse train by the data signal output circuit 21.
It begins to send out data signals.

The data signal output circuit 21 transmits the data signal through the line Ln using the second impedance.
For example, as the line current I ₂ flowing in a short circuit, I ₂
≒100~200mA (However, the following explanation is based on I ₂ = 200mA
), and therefore the data signal is transmitted in current mode.

FIG. 3 is a circuit diagram showing an embodiment of an interface circuit provided at the input stage of the receiver 1 in the embodiment of FIG. 1. By providing the interface circuit of FIG. 3, Even in the case where the function of the receiver is converted to a computer, consideration has been given so that the number of input ports to the computer will not increase significantly due to an increase in the number of lines.

First, to explain the configuration, the supply voltage of 24V to the line Ln in the steady monitoring state is carried out via a resistor R ₂ and a diode D ₆ . As a current detection circuit for detecting current I=20mA, a circuit including a transistor Q ₁ , bias resistors R ₁ to R ₃ and a capacitor C ₁ is provided, and the voltage generated across the resistor R ₂ by sending an alarm signal causes the transistor to _Q1 is on-biased to conduct and the transistor
The collector of Q ₁ is taken out to the receiver side as a representative fire signal E ₁ through a resistor R ₄ and a diode D ₂ ,
Further, the collector output of the transistor _Q1 is directly taken out to the receiver side via the resistor _R4 as a line fire signal Eln.

Also, the collector of transistor Q ₁ is connected to resistor R ₅ and
It is connected to the base of transistor Q ₂ which has a base bias circuit consisting of R ₆ , conduction of transistor Q ₁ makes transistor Q ₂ conductive, and resistor R ₂ ,
The transistor Q ₁ is configured to be self-maintained by the current flowing through R ₃ and the transistor Q ₂ .

In addition, the interface circuit is provided with a constant voltage circuit consisting of Darlington-connected transistors Q ₆ and Q ₇ , a resistor R ₁₆ , and a Zener diode ZD.
The constant voltage output of the constant voltage circuit by these transistors Q ₆ and Q ₇ is a constant voltage output of 20 V based on the Zener voltage of the Zener diode ZD, and in the steady monitoring state, the supply voltage from the diode D ₆ is Since 24V is higher than the constant voltage output 20V, use a diode.
_D7 is off and no constant voltage output is provided.

Also, a diode in series with the Zener diode ZD.
Transistor Q ₄ is connected through D ₅ , and this transistor Q ₄ is connected to the resistor in the steady monitoring state.
It is turned on by the base voltage given by the base bias circuit made up of R ₁₃ , R ₁₅ , diode D ₃ and resistor R ₁₂ to put into operation the constant voltage circuit made up of transistors Q ₆ and Q ₇ .

Next, the terminal device calling signal Ecn is outputted from the receiver side based on the representative fire signal _E1 outputted via the diode _D2 when the transistor _Q1 is turned on by receiving the alarm _signal . Connected to the base of transistor Q ₃ , this terminal ring signal
Since Ecn is a pulse signal with a constant period, transistor _Q3 is turned on by the terminal device calling signal Ecn.
Since the collector of transistor Q ₃ is connected to the base of transistor Q ₄ through diode D 3, when transistor Q ₃ is turned on, transistor Q ₄ is turned off, and when transistor Q ₃ is turned off, transistor Q ₄ is turned _off . turns on, transistor _Q4 turns on in response to the terminal call signal Ecn,
When off, the constant voltage circuit with transistors Q ₆ and Q ₇ is activated and stopped repeatedly, and when transistor Q ₄ is on, the constant voltage circuit outputs a constant voltage of 20V, but when transistor Q ₄ is off, the Zener diode Since the reference voltage setting by ZD is canceled, transistors Q ₆ and Q ₇ are turned on only by the bias from resistor R ₁₆ , and the power supply voltage of 30 V supplied through resistor R ₁₃ is connected to resistor R ₁₉ and diode D ₇ . The configuration is such that it is superimposed on the line Ln via the

Therefore, when the terminal calling signal Ecn from the receiver is input to the interface circuit, the transistor
By repeating the constant voltage operation and non-constant voltage operation of the constant voltage circuit by turning on and off Q3 and turning off and on the transistor _Q4 , the voltage of the line Ln changes in a pulse _- like manner in the range of 20V and 30V.

In addition, the transistor is activated by the alarm signal from the terminal device.
_Q1 is on. On the other hand, due to the load current flowing through resistors R ₂ and R ₃ to the terminal, the voltage on the anode side of diode D ₆ decreases, and the voltage on the anode side of diode D ₆ decreases.
The voltage supplied to Ln is 20 V or less, which is the output voltage of a constant voltage circuit including transistors Q ₆ and Q ₇ .

Furthermore, the interface circuit includes a transistor _Q5 and a resistor as a circuit for detecting the data signal sent in current mode by the terminal called by the receiver.
A current detection circuit for data signal detection consisting of _R13 is provided, and the resistor _R13 is a minute resistance of, for example, about 2Ω, and is a resistor only for the line current I = 200mA that flows due to the transmission of the data signal from the terminal.
The voltage generated across _R13 turns on transistor _Q5 , and a data signal Ed is sent to the receiver via resistor _R9 and diode _D1 connected to the collector of transistor _Q5 .
I am trying to output .

Furthermore, the collector of the transistor _Q5 for data signal detection is configured to take out the trouble signal _E4 caused by a line short circuit via the diode _D9 , and the anode side of the diode _D9 is connected to the resistor.
An integrating circuit consisting of R ₂₁ and capacitor C ₅ is connected,
A line short circuit is detected from the output of diode D ₉ when the charging voltage of capacitor C ₅ reaches a certain voltage after a certain period of time that is longer than the reception time of the data signal from the terminal after transistor Q ₅ is turned on. There is.

Also, the connection point between resistor R ₂₁ and capacitor C ₅ is the resistor
It is connected to the base of transistor _Q4 via _R22 and diode _D8 , and when a short-circuit problem is detected, turning on transistor _Q4 forces the constant voltage circuit consisting of transistors _Q6 and _Q7 to operate. Therefore, the supply voltage of 30V required for sending data signals from the terminal device is lowered to a constant voltage of 20V, thereby prohibiting the sending of data signals.

Note that transistor Q ₈ connected in parallel to the constant voltage circuit consisting of transistors Q ₆ and Q ₇ is a current limiting circuit that turns on and cuts off transistors Q ₆ and Q ₇ when the current flowing through line Ln exceeds 300 mA. It consists of

Of course, the interface circuit shown in FIG.
It is provided for each line L ₁ to Ln in the figure, but
Short circuit trouble E ₄ d, each output of representative fire E ₁ is connected to the same line as other interface outputs.

FIG. 4 is a circuit block diagram showing a specific embodiment of the receiver 1 in the embodiment of FIG. 1 together with the interface circuit shown in FIG. 3.

First, to explain the configuration, the interface circuit 24 is provided as interface circuits 24a to 24n for each line L ₁ to Ln, and a representative fire signal E ₁ of each interface circuit 24a to 24n is provided.
is compiled and output, and also a line fire signal.
El ₁ to Eln are each interface circuit 24a to 24n
Furthermore, terminal calling signals Ec ₁ to Ecn
The data signal is given to each interface circuit 24a to 24n of
A terminal is provided to output Ed to the receiver side.

Representative fire signal from interface circuit 24
E ₁ is input to each of the monostable multivibrator 25 and the delay circuit 29, and the representative fire signal E ₁
The decoder 27, counter 43, counter 51, and latch circuit 48 are reset by the output of the monostable multivibrator 25 via the OR gates 26, 46, 47, and 53, respectively.

The output of the delay circuit 29 to which the representative fire signal E ₁ is input is connected to an oscillation circuit 32 via an AND gate 31, and this oscillation circuit 32 receives the representative fire signal E ₁ ,
That is, when an alarm signal is received from the terminal, it is activated and outputs an oscillation pulse for sequentially scanning the line.

The output of the oscillation circuit 32 is given to a decoder 27, and the decoder 27 sequentially produces H level outputs at output terminals _Q1 to Qn in response to the oscillation pulses of the oscillation circuit 32.

Note that the final output terminal Qn of the decoder 27 is given to the monostable multivibrator 28,
The number of terminals up to terminal Qn=1 in 7 corresponds to the number of lines L ₁ to Ln, and when the final output terminal Qn becomes H level, the output of the monostable multivibrator 28 resets the decoder 27 via the OR gate 26. state.

Each of the output terminals Q ₁ to Qn−1 of the decoder 27 has a number of AND gates 3 corresponding to the lines L ₁ to Ln.
3a to 33n, and AND gates 33a to 33n.
Line fire signals El ₁ to Eln from the interface circuit 24 are input to the other terminal 33n.

Therefore, when the AND gate inputting the line fire signal is selected by the output of the decoder 27, the selected AND gate produces an H level output.

The outputs of the AND gates 33a to 33n are input to the NOR gate 36, and the output of the NOR gate 36 is given to the oscillation circuit 32 via the OR gate 30 and the AND gate 31. When the L level output is generated, the AND gate 31 is inhibited via the OR gate 30, and the oscillation of the oscillation circuit 32 is stopped. Further, the output of the NOR gate 36 is applied to an oscillation circuit 40 via an inverter 37 and an AND gate 39, and the output of a latch circuit 48 that latches the start pulse of the data signal Ed is applied to the other side of the AND gate 39. The oscillation circuit 32 stops oscillating with the L level output of the NOR gate 36, and at the same time, the AND gate 39, which is in an allowable state with the H level output of the inverter 38, starts the oscillation circuit 40 with the H level output of the inverter 37. I try to do that.

This oscillation circuit 40 is used to send a paging pulse signal to a plurality of terminals connected to the line selected by the output of the decoder 27 when the oscillation circuit 32 is in a stopped state.

That is, the output of the oscillation circuit 40 is inputted to each of the AND gates 42a to 42n provided for each of the lines _L1 to Ln via the OR gate 41, and any one of the AND gates 42a to 42n is inputted when the oscillation circuit 32 is stopped. Since the specific terminal output of the decoder 27 is in the permissible state, the terminal ring signal, that is, the oscillation pulse of the oscillation circuit 40, is output to any selected line via the AND gate in the permissible state. Become.

When the terminal device detecting a fire is called by the oscillation pulse of the oscillation circuit 40 and outputs a data signal in response to the call, the data signal Ed received by the interface circuit 24 is sent to the latch circuit 48 and The configuration is such that the signal is applied to each of the conversion circuits 55.

The latch circuit 48 latches the start pulse of the first received data signal Ed, inverts this latch output to L level with the inverter 38, and disables the AND gate 39, thereby causing the oscillation circuit 4
The oscillation circuit 40 stops calling the terminal device until the oscillation operation of 0 is stopped and reception of the data signal is finished.

Further, the output of the latch circuit 48 is configured to operate an oscillation circuit 50 via a delay circuit 49.
The oscillation pulse of the oscillation circuit 50 is given as a clock pulse to the serial-to-parallel conversion circuit 55.
5, the data signal consisting of a pulse train inputted from the interface circuit 24 is converted into parallel data, and the converted data is outputted to the processing circuit 60 for displaying the fire detection stage and address based on the received data. There is.

Further, the output of the oscillation circuit 50 is given to a counter 51, and a count value corresponding to the number of pulses of the received data is set in the counter 51. When the counter 51 reaches a full count, the data signal is
At the end of receiving Ed, a counter output is given to the monostable multivibrator 52, and the output of the monostable multivibrator 52 resets the latch circuit 48 via the OR gate 47. 51 itself is reset.

The reset of the latch circuit 48 based on the count output of the counter 51 causes the oscillation circuit 40, which had been stopped by the latch output of the latch circuit 48, to restart its oscillation operation.

On the other hand, the output of the oscillation circuit 40 that outputs the paging pulse signal of the terminal device is given to a counter 43, and a count value corresponding to the number of terminal devices connected to the line is set in the counter 43. , when the count value of the counter 43 reaches the set count, the monostable multivibrators 44 and 45 are operated in sequence to reset the counter 43 and the OR gate 3 is activated.
0 and the AND gate 31 to restart the oscillation operation of the oscillation circuit 32 which is in a stopped state, and the decoder 2
7 to restart the line scanning.

Next, the operation of the embodiment of the present invention shown in FIGS. 2, 3 and 4 will be explained with reference to the time chart in FIG.

First, consider the case where the number of lines L ₁ to Ln drawn out from the interface circuit 24 of the receiver 1 shown in FIG. 4 is 10 lines, and 10 terminals are connected in parallel to each line. Take for example.

In the steady monitoring state, a power supply voltage of 24V is supplied to the lines _L1 to _L10 through the resistor _R2 and diode _D6 of each interface circuit shown in FIG.

In this state, for example, suppose that the sensor section of the second terminal (address code 000010) connected in parallel to the fifth line _L5 detects a fire and outputs a first-stage fire detection signal with first-class sensitivity. , the operating time of the monostable multivibrator _14c is determined by the detection signal of the sensor unit 2 in the terminal device shown in FIG. , an alarm signal is sent to the receiver by flowing line current I=20 mA.

In response to the alarm signal sent from the terminal, a current I ₁ =20 mA flows through the resistor R ₂ of the interface circuit shown in Figure 3 due to the output of the alarm signal, and the voltage generated across the resistor R ₂ turns on the transistor Q ₁ , causing the resistor Output a representative fire signal E ₁ through R ₄ and diode D ₂ ,
Further, the fact that the line _L5 is in the fire detection state is outputted as a line fire signal _El5 , and when the transistor _Q1 is turned on, the transistor _Q2 is also turned on, and the transistor _Q1 is self-maintained in the on state.

Typical fire signal detected in the interface circuit by reception of alarm signal from line L ₅ in this way
E ₁ is given to each of the monostable multivibrator 25 and delay circuit 29 of the receiver shown in FIG. , to the latch circuit 48 and the counter 51, thereby canceling their respective reset states.

After this reset is released, the delay circuit 29 generates an H level output, and the AND gate 31 in the allowable state generates an H level output via the OR gate 30 due to the H level output of the NOR gate 36, and the oscillation circuit 32
operate.

The operation of this oscillation circuit 32 provides an oscillation pulse to the decoder 27, and the decoder 27
AND gate 33 provided corresponding to L ₁ to _{L 10}
A, 33b, ... are output sequentially and a line fire signal is generated.
The decoder output to the fifth AND gate to which El ₅ is input causes the fifth AND gate to produce an H level output, so that the output of the OR gate 36 falls from the H level to the L level. Therefore, the AND gate 31 is inhibited by the L level output of the NOR gate 36 via the OR gate 30, and the oscillation circuit 32 stops operating after outputting the fifth oscillation pulse.

On the other hand, the L level output of the NOR gate 36 is made H level by the inverter 37, and the inverter 38 outputs the H level.
The level output is applied to the oscillation circuit 40 via the AND gate 39 which is in a permissive state, and the oscillation circuit 40 starts oscillation operation.

The oscillation pulse of the oscillation circuit 40 is applied via an OR gate 41 to each of AND gates 42a, 42b, . Since the fifth AND gate in the AND gates 33a, 33b, etc. is in a permissible state with an H level output, the oscillation pulse of the oscillation circuit 40 is transmitted to the corresponding line _L5 via the fifth AND gate. The signal is output to the interface circuit 24 as a device call signal _Ec5 .

In this way, the terminal calling signal Ec ₅ outputted to the interface circuit by the oscillation pulse of the oscillation circuit 40 in FIG. 4 is input to the transistor Q ₃ of the interface circuit in FIG. At the same time, when transistor _{Q 3 is} turned on and off, transistor Q ₄ is turned on and off, and when transistor Q ₄ is turned off, the Zener diode ZD is disconnected, and the constant consisting of transistors Q ₆ and Q ₇ is turned on and off. Voltage circuit is a diode
Supply a voltage of 30V to line L ₅ via D ₇ ,
On the other hand, when transistor _Q4 is turned on, a constant voltage output of 20V based on Zener diode ZD is sent to line _L5 .

That is, the interface circuit superimposes a calling pulse signal having a voltage change of 10V rising to 30V with the constant voltage output of 20V as a reference level on the line _L5 based on the input of the terminal device calling signal _Ec5 from the receiver.

In this way, the voltage mode calling pulse signal superimposed on line _L5 from the interface circuit is
The detection signal from the sensor unit 2 shown in the figure activates the alarm signal output circuit 7 and is detected by the ringing signal detection circuit 8 of the terminal 3 which outputs the alarm signal, and is first detected via the pulse delay circuit 9. The reset release circuit 10 is activated by the ring pulse signal, and the counter circuit 11 and the decoder circuit 16 are reset. When a second ring pulse is subsequently detected, this ring pulse is counted by the counter circuit 11. In the matching circuit 13, the address setting circuit 12
The address code assigned to the second terminal device is compared with the preset address code assigned to the second terminal device.

In this case, since this is the second terminal device, the address setting circuit 12 is set with a binary code of "2" in decimal notation, and therefore the counter circuit 11 counts the third calling pulse signal. The matching circuit 13 determines that the count output when the count is counted 2 matches the set address of the address setting circuit 12, and the monostable multivibrator 14
output to each of a and 14b. In response to the output of the matching circuit 13, the monostable multivibrator 14a outputs an output to activate the switch circuit 17,
The constant voltage output of the constant voltage circuit 6 is supplied to the AD conversion circuit 18, and the first stage detection signal detected by the sensor unit 2, that is, the detection signal based on the first type sensitivity, is converted into a digital code, for example, "100". Then, it is output to AND gates 22a, 22b, . . . (however, the number of AND gates corresponds to the number of bits of the AE conversion circuit 18).

Subsequently, the monostable multivibrator 14b generates an output to operate the oscillation circuit 15, and the oscillation pulses of the oscillation circuit 15 are input to the decoder circuit 16, which sequentially outputs pulse signals to the output terminal of the decoder circuit 16. Therefore, a start pulse is generated from the OR circuit 19 by the sequential output of the decoder 16, and the AD conversion circuit 18
The pulse representing the fire detection stage, the address code of the terminal device 3 preset in the data setting circuit 22, and the end pulse are sequentially output, and this pulse train from the OR circuit 19 is converted into the oscillation pulse of the oscillation circuit 15 by the AND gate 20. The signals are sequentially applied to the data signal output circuit 21 in synchronization with the data signal output circuit 21.

Here, the pulse train given to the data signal output circuit 21 is, for example, "1100000010 space 1", the first bit is the start pulse, the next three bits represent the fire detection stage, and the next six bits are the address. The final bit that becomes data and enters after the space becomes the end pulse.

The data signal output circuit 21 short-circuits the line L ₅ with the second impedance for the pulse corresponding to bit "1" in the pulse train given by the AND gate 20, and short-circuits the line L ₅ with the second impedance to I ₂ =100. A line current in the range of ~200 mA, for example I ₂ =200 mA, is applied to send the data signal to the receiver in current mode.

When the terminal device sends a data signal to the receiver in this way, a line current of I = 100 to 200 mA flows due to the first start pulse in the interface circuit shown in Fig. 3 due to the sending of the data signal, and this line current The voltage generated across the resistor _R13 turns on the transistor _Q5 , and outputs a start pulse reception signal to the receiver circuit of FIG. 4 via the resistor _R9 and the diode _D1 . The reception signal of this start pulse is latched by the latch circuit 48 of the receiver circuit in FIG.
9 is set to a prohibited state, and the oscillation operation of the oscillation circuit 40 is prohibited.

That is, the oscillation circuit 40 stops its oscillation operation upon receiving the data signal when the second terminal connected to the line _L5 is called.

Note that the output of the oscillation circuit 40 is fixed at H level when the oscillation operation is stopped.

Therefore, when the oscillation circuit 40 stops oscillating, the transistor in the interface circuit of FIG.
The base input of Q ₃ is fixed at H level, and transistor Q ₄ is fixed off when transistor Q ₃ is turned on. As a result, Zener diode ZD is disconnected, and the constant voltage function of transistors Q ₆ and Q ₇ is lost. , the supply voltage to line L ₅ is 30V, and the line voltage is kept low while data is being sent from the terminal.
Keep it at 30V.

On the other hand, the latch output of the start pulse latched by the latch circuit 48 in the receiver circuit of FIG.
The data signal Ed, which is input following the start pulse, is converted into parallel data by the serial-parallel conversion circuit 55 and output to the processing circuit 60. Since the detection information is "100" and the address information is "000010", it is determined from the fire detection information that it is in the first type fire detection stage and displayed, and the second terminal of line L ₅ is detected from the address information. indicates that the fire was detected by the device. Further, the oscillation pulses of the oscillation circuit 50 for the serial-to-parallel conversion circuit 55 are counted by a counter 51, and when the oscillation pulses corresponding to the number of received pulses of the data signal are counted, the counter 51 generates an output to the monostable multivibrator 52. Latch circuit 48 via OR gate 47
Reset.

Further, the counter 51 and the serial-to-parallel conversion circuit 55 are also reset via the monostable multivibrator 54 and the OR gate 53 after a certain period of time.

When the latch of latch circuit 48 is reset,
The output of the inverter 38 becomes H level, and the AND gate 39 generates an output, and the oscillation circuit 40, which is in a stopped state, restarts the oscillation operation at the H level output, and sends out the calling pulse signal to the line _L5 again. Become.

In this way, when the number of ringing pulse signals generated by the oscillator circuit 40 reaches the number of the ten terminals provided on the line _L5 , the counter 43 generates an output, which sequentially triggers the monostable multivibrators 44 and 45. After a certain period of time, the counter 43 is reset via the OR gate 46, and the oscillation circuit 32, which was in a stopped state, is scanned via the OR gate 30 and the AND gate 31 for the fifth line _L5 .
oscillation operation is restarted, and line scanning for the remaining lines L ₆ to _{L 10} is resumed.

When all lines have been scanned by this oscillation circuit 32, the final terminal of the decoder 27
The monostable multivibrator 28 is triggered by the output of Qn, the decoder 27 is reset via the OR gate 26, and the next oscillation pulse from the oscillation circuit 32 starts line scanning from line _L1 again, and the same goes for the above. This action will be repeated.

Although the above embodiment takes as an example the case where the sensor section of the terminal device outputs a fire detection signal with three sensitivities, the present invention is not limited to this, and the present invention It may also be possible to detect temporal changes in surrounding physical phenomena caused by a fire.

As described above, according to the present invention, a sensor unit is provided between a pair of power supply signal lines drawn out from a receiver, which outputs detection signals in multiple stages according to changes in surrounding physical phenomena caused by a fire. Fire alarm equipment connects multiple terminals in parallel and sends fire detection information based on the detection signal of the sensor and address information of the terminals from the terminals to the receiver as data signals, in a steady monitoring state. In this case, the paging scanning from the receiver is stopped, and the cyclic paging scanning of the terminal device by the receiver is started only when the alarm signal sent out when a fire is detected by the sensor section of the terminal device is received. When the terminal that sent the alarm signal is called, the receiver stops calling scanning,
In this stopped state, the terminal device sends a data signal consisting of fire detection information and address information set in the terminal device to the receiver for display processing, and after receiving this data, the call is resumed and the above operation is repeated. Therefore, in the steady monitoring state where no fire detection is performed on the terminal side, the receiver stops paging scanning of the terminal, and the terminal is only supplied with power from the receiver's power supply. This makes it possible to significantly reduce the current consumption in the receiver and terminal device compared to conventional devices that constantly perform cyclic paging scanning of the terminal device. Since the circuit for scanning calls in the machine and the circuit for decoding calls in the terminal and sending out the presence or absence of a fire detection signal are not always in operation, the circuit elements that make up these circuits are The effect is that deterioration is significantly reduced and a fire alarm system with excellent durability and reliability can be obtained.

On the other hand, when a fire is detected in the sensor section of one of the terminals, the receiver starts paging scanning of the terminal upon receiving an alarm signal sent from the terminal,
This paging scan is performed by sending a paging pulse signal that changes the power supply voltage supplied to the terminal to a predetermined voltage level, for example, if the power supply voltage in the steady monitoring state is 24V, the voltage level changes to 30V. This call signal is determined only by the terminal device that detects a fire and sends out an alarm signal, and when it matches the preset call code, the fire detection information indicating the detection stage and the terminal device A data signal consisting of the address information set in Even if the signal is received and processed, and the terminal device is called and the data signal is sent from the terminal device using the same power signal line from the same receiver, the transmission mode of the calling signal and the data signal are different. This ensures that malfunctions due to mutual interference between the ringing signal receiving system and the data signal receiving system are prevented, and that the voltage and current in the sending of the calling signal in the voltage mode and the data signal in the current mode are controlled. By setting the power supply voltage and monitoring current to a sufficiently high level in the steady monitoring state, the S/N ratio of the calling signal and data signal with respect to noise components is increased, and furthermore, the signal to noise ratio of the calling signal and data signal from the terminal device is improved. During transmission, the power supply voltage from the receiver to the terminal device is higher than in the steady monitoring state, so the voltage drop due to the line impedance caused by the transmission of the call signal and data signal causes a significant drop in the power supply voltage to the terminal device. This also provides the advantage that all terminal devices can operate stably at all times.

In addition, by installing a circuit on the receiver side that counts the oscillation circuit for the terminal ringing signal and determines which terminal is being called, and comparing it with the address information from the terminal, more accuracy can be achieved. It is good to be able to determine the address of the terminal device.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the equipment configuration of the present invention, FIG. 2 is a circuit block diagram showing an embodiment of the terminal device of the present invention, and FIG. 3 is a block diagram of the interface circuit used in the receiver of the present invention. FIG. 4 is a circuit block diagram showing an embodiment of the receiver circuit according to the present invention. FIG. 5 is a time chart showing signal waveforms of various parts in the receiver circuit. . 1... Receiver, 2, 2a, 2b, 2n... Sensor unit, 3, 3a, 3b, 3n... Terminal, 4...
Terminal resistor, 5... Diode bridge, 7... Alarm signal output circuit, 8... Calling signal detection circuit, 11
... Counter circuit, 12 ... Address setting circuit,
13... Matching circuit, 15... Oscillation circuit (for data transmission), 16... Decoder circuit, 18... AD conversion circuit, 23... Display circuit, 24, 24a-24
n...interface circuit, 27...decoder,
32...Oscillation circuit (for line scanning), 40...Oscillation circuit (for calling signal), 48...Latch circuit, 50
...Oscillation circuit (for data reception), 55...Serial-to-parallel conversion circuit, 60...Processing circuit, _L1 to Ln...Line,
C...Common line.

Claims (1)

[Scope of Claims] 1. A plurality of terminal devices having sensor sections that output detection signals in multiple stages according to changes in surrounding physical phenomena due to a fire, between a pair of power supply/signal lines drawn out from a receiver. In a fire alarm system in which the terminals are connected in parallel and fire detection information based on the detection signal of the sensor section and the address information of the terminals are sent to the receiver as data signals, the terminals include the above-mentioned terminals. an alarm signal output circuit that short-circuits the power supply/signal line with a first impedance for a predetermined time based on a detection signal from the sensor unit and sends an alarm signal to the receiver; and a caller that detects a call pulse signal from the receiver. When the count value of the signal detection circuit and the counter that counts the ringing pulses detected by the ringing signal detection circuit matches the address information set in the terminal, fire detection information and the corresponding a data signal output circuit that converts a coded signal of address information of a terminal device into a pulse train, shorts the power supply signal line to a second impedance in response to the pulse train, and sends a data signal to a receiver; The receiver is provided with an alarm receiving circuit that receives alarm signals from each terminal device, and a ringing signal output that superimposes a ringing pulse signal on the voltage supplied to the terminal device and outputs a ringing pulse signal based on the reception output of the alarm receiving circuit. a data receiving circuit that receives a data signal from a terminal;
a display processing circuit that displays the stage of change in physical phenomena due to fire and the address of the terminal device that outputs the data signal based on the data signal received by the data receiving circuit; A fire alarm system comprising: a voltage control circuit that maintains the supply voltage of the device at a voltage higher than the supply voltage in a steady monitoring state by a predetermined value.