JP2830890B2 - Gas alarm shutoff system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas alarm shut-off system having a gas leak alarm, a gas meter and a gas shut-off valve, and more particularly to a gas leak alarm and a gas meter which are connected by two signal lines. The present invention relates to a gas alarm shut-off system for transmitting and receiving signals between a gas leak alarm and a gas meter through signal lines.

[0002]

2. Description of the Related Art Conventionally, as an example of this type of system, it is determined whether or not a check signal sent from a gas meter through a signal line at regular time intervals returns through a signal line to connect / disconnect a gas leak alarm. And a pulse signal is transmitted from the gas meter side through a signal line at a short fixed cycle, and this pulse signal returns through a means provided on the gas leak alarm device and turned on in response to gas leak detection. It has been proposed to determine whether or not gas leakage has occurred. In the proposed device, when the signal line is wetted with water and short-circuited, the same state as when gas leakage occurs occurs, and the gas supply valve can be operated to shut off the gas supply.

Further, as another example, a means for turning on the power when the power is turned on is provided on the gas leak alarm side, and a check signal sent from the gas meter is transmitted via a signal line because the means is turned off. There has been proposed a device that can detect that the power is not turned on by not returning.

[0004]

However, in the above-mentioned conventional example, it is impossible to detect whether the power is not turned on due to a power failure or disconnection of an outlet. For this reason, when the gas meter further notifies the centralized monitoring center, a notification is sent from the gas meter in the area to the centralized monitoring center at the same time in the event of a power outage, and there is a possibility that the center cannot process the information.

[0005] Further, since it is not possible to distinguish whether the gas interruption is due to a gas leak or a short-circuit of a signal line, there has been a problem that it is not possible to take appropriate measures after the gas interruption.

Accordingly, in view of the above-mentioned conventional problems, the present invention is capable of distinguishing and detecting a disconnection of a signal line, a gas alarm, a power failure, a disconnection of a power outlet, and a short circuit of a signal line on the gas meter side. It is intended to provide a gas alarm shutoff system.

[0007]

In order to achieve the first object, a gas alarm shutoff system according to the present invention comprises:
As shown in the basic configuration diagram of FIG. 1, two signal lines L ₁ , L
_In a gas alarm shutoff system having a gas meter 1 and a gas leak alarm 2 interconnected by 2 and a gas shutoff valve 13 provided in a gas supply path 12, the gas meter 1 checks one of the signal lines. A signal is periodically transmitted, and the disconnection detecting means 11a for detecting disconnection of the signal line depending on whether the check signal returns via the other signal line, and during the transmission period of the check signal, A voltage supply control signal is transmitted to the other of the signal lines at fixed time intervals, and the number of the voltage supply control signals returned via one of the signal lines in response to the transmission causes a power failure or gas leakage on the gas leakage alarm device side. The disconnection valve is controlled based on detection by the disconnection detecting means 11b for determining whether the outlet is disconnected or the signal line is short-circuited, and detecting the disconnection detecting means and the determination detecting means. Control means 11c, wherein the gas leak alarm 2 is provided at a unidirectional element 25b which enables conduction from one side of the signal line to the other, and at a gas leak alarm side end of the signal line. Switching means 27b
An answer transmitting means 21a for receiving the check signal transmitted through the signal line during a non-power failure, and transmitting an answer signal for turning on the switching means for a first fixed time in response to the check signal; The alarm transmitting means 21b sends out a gas alarm signal for turning on the switching means for a second fixed time in response to the alarm, and sends out the outlet disconnection signal for turning on the switching means for a third certain time in response to the detection of disconnection of the outlet. It is characterized by comprising outlet outlet transmission means 21c.

[0008]

[Action] With the above configuration, when it is properly connected between the signal lines L ₁ and L ₂ of the gas meter 1 and a gas leak alarms 2, disconnection detecting means 11a of the gas meter 1, the one signal line L ₁ After transmitting the check signal periodically, so check signal is returned via the unidirectional element 25b and the other signal line L ₂ of the gas leak alarm 2, whereby it is possible to detect the disconnection of the signal line.

The discrimination detecting means 11b outputs a check signal
, And before the next transmission, the other signal line L_TwoConstant
The voltage supply control signal transmitted at the time interval is the signal line L₁Passing
And L _TwoIs not short-circuited and the gas leak alarm 2 side
When the switching means 27b is turned off,
Signal line L₁Will not return to the gas meter side via
No. However, the answer transmission means 21a disconnects the
Receive the check signal sent through the
To turn on the switching means for a first fixed time
A signal is sent out, and the alarm transmission means 21b detects a gas leak.
A gas that turns on the switching means in response to a second predetermined time
An alarm signal is sent out and the outlet disconnection transmitting means 21c
Switches the switching means in response to the detection of outlet disconnection.
3. An outlet disconnection signal that is turned on for a certain period of time is transmitted.

Accordingly, determination detecting means 11b is counted come voltage supply control signals back via one of the signal lines L ₁ in accordance with the delivery, the power failure of the gas leak alarm side by their number, gas leakage, electrical outlet The control unit 11c can detect and detect the disconnection and the short-circuit of the signal line, and the control unit 11c detects the cutoff valve 13 by the detection by the two detection units 11a and 11b.
Can be appropriately controlled, and the necessity of notification can be determined according to the detected content.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.
I do. FIG. 2 shows a gas alarm shut-off system according to the present invention.
It is a figure which shows an Example, In this figure, the inside of the gas meter 1 is shown.
The control unit 11 operates according to a predetermined control program.
Consists of a working microcomputer (CPU)
Output port O₁~ O_FourAnd input port I₁~ I _ThreeTo
And a control program (not shown) stored therein.
A built-in RAM for storing the OM and various data. output
Port O₁Is the check signal SG₁, Output port O_TwoIs
Power supply control signal SG_Two, Output port O_ThreeIs the cutoff signal SG
_ThreeAnd output port O_FourIs the notification signal SG_FourEach
Output. Input port I₁Is the answer signal SG_Five, Gas police
Notification signal SG₆And outlet disconnect signal SG₇, Input port
I_TwoIs the connection detection signal SG₈And input port I_ThreeIs
Shutdown state signal SG₉Enter each.

[0012] Output port O ₁ for outputting a check signal SG ₁ is the emitter DC power source, a collector connected to the base of PNP transistor Q ₁ which is connected to the terminal T _11, L check signal SG ₁ from H transistor Q ₁ by falling to the level is biased on, the DC power source voltage is supplied to the terminal T _11. Output port O ₂ for outputting a voltage supply control signal SG ₂ is the emitter DC power source, a collector connected to the base of PNP transistor Q ₂ to which are respectively connected to the terminal T _12, the voltage supply control signal SG ₂ from H transistor Q ₂ by falling to the L level is biased on, the DC power source voltage is supplied to the terminal T _12. Terminals T ₁₁ and T ₁₂ are respectively connected to the terminals T ₂₁ and T ₂₂ of the gas leak alarm 2 via the two signal lines L ₁ and L _2.

[0013] The output port O ₃ to output a shut-off signal SG ₃
Is connected to a valve drive circuit 14 for driving the gas cutoff valve 13 provided in the gas supply path 12, an output port O ₄ for outputting a notification signal SG ₄ is a remote centralized monitoring through the transmission line L ₃ such as a telephone line It is connected to the notification device 15 connected to the center.

The input port I ₁ has a collector connected to a DC power supply,
To ground the emitter and base connected to the collector of NPN transistor Q ₃ which are respectively connected to the terminal T _11, the input port I ₂ has a collector DC power supply, the emitter grounded, and the base respectively to the terminal T ₁₂ and it is connected to the connected collector of the NPN transistor Q _4. The input port I ₃ is connected to a DC power supply via a state detection switch 16 which is turned on / off according to the state of the gas cutoff valve 13.

On the other hand, the gas leak alarm 2 uses a battery as a power source.
Rectifies and stabilizes the commercial AC power unlike the gas meter 1
DC power supply and backup power supply
Operating according to the control program
And a control unit 21 configured by a CPU (CPU).
This control unit 21 has an input port I₁₁~ I₁₃And output port
O₁₁And stores a control program (not shown)
Built-in ROM and RAM for storing various data
You. Input port I₁₁Gas detection signal SG₁₁, Input port
I₁₂Is the check signal SG₁And input port I₁₃
Is the outlet disconnection detection signal SG₁₂Enter each.
Output port O₁₁Is the check signal SG₁Corresponding to the input
Sensor signal SG_Five, Gas alarm signal SG₆And without outlet
Signal SG ₇Are output.

Gas leak detection signal SG₁₁Input port
I₁₁Is the detected gas concentration from the gas leak sensor 22.
The corresponding gas detection signal is compared with the reference voltage of the reference voltage source 23.
Is connected to the output of the comparator 24 for comparison.
Outgoing signal SG₁₁Is larger than the reference voltage
Then, it falls from H to L level. Check signal SG ₁
Input port I to input₁₂The collector is a DC power supply,
Phototransistors with their respective emitters connected to ground
Connected to the collector of the power supply 25a. Photo transient
The star 25a has a terminal T_{twenty one}Anode, terminal T_{twenty two}To Casor
And the light emitting diode 25b to which the diodes are respectively connected.
A photocoupler 25 is constituted. Outlet
Detection signal SG₁₂Input port I to input₁₃Is, for example,
No. 63-147795 or No. 63-1477
Outlet detection proposed by No. 96 etc.
It is connected to the output of the circuit 26. Answer signal SG_Five,
Gas alarm signal SG₆And outlet disconnect signal SG₇Out
Output port O₁₁The anode is connected to a DC power supply
Connected to the cathode of the light emitting diode 27a
I have. The light emitting diode 27a has a terminal T_{twenty one}An emitter,
Terminal T_{twenty two}Are connected to the photo
The photocoupler 27 is configured together with the transistor 27b.
I have.

An outline of the operation of the system having the above-described configuration will be described below with reference to waveform diagrams showing states of respective parts in FIG.
The control unit 11 of the gas meter 1 changes the output port O ₁ , which is always at the H level, to the L level every 60 seconds, for example, and outputs the check signal SG _{1. In} response to this, the transistor Q ₁ is shown in (a). To turn on. By turning on the transistor Q _1, when the gas leak alarm 2 via the signal line L ₁ and L ₂ is connected, the transistor Q ₁ from the DC power supply, terminal T _11, the signal line L _1, the terminal T _21, light-emitting diodes 25b, the terminal T _22, the signal line L _2, the terminal T _12, a current i ₁ to the ground through a bias resistor of the transistor Q ₄ flows, the transistor Q ₄ is turned on. Falling input port I ₂ of the control unit 11 by the on of the transistor Q ₄ is from H to L level, since this is input to the control unit 11 as the connection detection signal SG _8, the control unit 11 by the input of the signal SG ₈ determines that gas leakage alarm 2 via the signal line L ₁ and L ₂ is normally connected.

A check signal SG from the control unit 11
₁LED 25b is turned on by sending
Therefore, the phototransistor 25a is turned on, and gas leakage occurs.
Input port I of alarm 2₁₂Falls from H to L level
This is the check signal SG ₁Input to the control unit 21 as
Is done. This check signal SG₁Control unit according to the input of
21 is an output port for, for example, 0.4 seconds after 1.25 seconds
O₁₁Signal from the H level to the L level₁₁Send out
You. This answer signal SG₁₁Light-emitting diode
The lamp 27a lights up and the photo
The transistor 27b is turned on.

On the other hand, the control unit 11 outputs a check signal S
Following delivery of G _1, an output port O is always H level
₂ was once L-level for a predetermined period to turn on the transistors Q ₂ and then for example a short period several times L level, for example 0.2 seconds after 1 second. In this case the phototransistor 27b is turned on, the transistor Q ₃ and the current i ₂ flows are turned on, thereby answer signal SG ₅ are input to the input port I _1. The control unit 11 subsequently repeat when the L-level for a predetermined period until the delivery of the next check signal every second sends a voltage supply control signal SG _2, the transistor Q ₂ in accordance with this (b) Turn on as shown.

The control unit 21 of the gas leak alarm 2 is
Upon detection of a gas leak by a signal from the gas leakage sensor 22, lights the light emitting diode 27a sends out a gas alarm signal SG ₆ to the output ports O _11, for example, in a 5 second interval for example 5 seconds L level at 5 second intervals As a result, the phototransistor 27b is turned on every 5 seconds as shown in FIG. The control unit 21, outlet exits the outlet omission detection signal SG ₁₂ is input from the detection circuit 26, the light emitting diodes 27a and sends the outlet missing signal SG ₇ by the output port O _11, for example, in two seconds L level Is turned on for 2 seconds, whereby the phototransistor 27b is turned on for 2 seconds as shown in FIG.

As described above, the transistor Q_TwoTurned on
At this time, if the phototransistor 27b is on,
Of the transistor Q_Two,
Terminal T₁₂, Signal line L_Two, Terminal T_{twenty two}, Phototransistor
27b, terminal T_{twenty one}, Signal line L ₁, Terminal T₁₁, Transis
TA Q_ThreeCurrent i to the ground through the bias resistor_TwoFlow
And the transistor Q_ThreeIs as shown in (g) to (i).
Is performed. This transistor Q_ThreeControl unit by turning on
11 input ports I₁Falls from H to L level,
This is the answer signal SG_Five, Alarm signal SG₆, Outlet
Missing signal SG₇Is input to the control unit 11.

The control unit 11, the input of the answer signal SG _5, power is supplied normally determines that gas leakage alarm 2 is operating normally, gas leak alarm when the answer signal SG ₅ is not input It is determined that power is not supplied to the unit 2 due to a power failure or disconnection of an outlet. Further, based on the input of the alarm signal SG ₆ , it is determined that the gas leak is detected in the gas leak alarm 2, and in response to this, the shutoff signal SG ₃ is output from the output port O ₃ and the gas is output to the valve drive circuit 14. The shut-off valve 13 is driven to shut off. Further, the input of the outlet missing signal SG _7, it is determined to be caused by dropout outlet of the gas leak alarm 2 not input the answer signal SG _5.

The phototransistor 27b is turned on.
The signal line L₁And L_TwoBut
When the photo is taken, the photo
The state where the transistor 27b is always on is formed.
As with, current flows through the short,
As shown in FIG._TwoIn sync with
Transistor Q_ThreeWill also turn on. This transi
Star Q_ThreeTurns on the input port I of the control unit 11₁But
Falling from H to L level, this is the water wetting signal
It is input to the control unit 11. The input of this water wetting signal
Signal line L₁And L _TwoShort-circuited by water
Judge.

Based on the above judgment, the control unit 11
, When necessary notification signal SG ₄ from the output port O ₄
Is output to the notification device 15 as a transmission line L ₃ such as a telephone line.
Through the centralized monitoring sensor to notify the user of the disconnection, gas alarm, unplugged outlet, and wetness.

The details of the operation of the system outlined above will be described below with reference to the flowcharts of FIGS. 4 to 4 showing the processing performed by the CPUs constituting the control units 11 and 21 in accordance with a predetermined program.

First, the CP of the control unit 11 on the gas meter 1 side is used.
U performs the processing shown in the flowcharts of FIGS. 4 to 8 started every 60 seconds, and performs the first step S10.
At 1, the output port O _{1 is set} to the L level, thereby turning on the transistor Q ₁ . Subsequent step S10
In 2, wait for the time T1 (for example, 0.1 second) to elapse. Time T1 is the input port I ₂ proceeds to step S103 after a lapse determines whether the L level.

The transistor Q₁Is on, the signal
Line L₁Or L_TwoIs disconnected or not connected, the current i
₁Does not flow, so transistor Q_FourInput port without turning on
I _TwoRemains at the H level, and the
Is NO, the process proceeds to step S104, and the output is performed here.
Port O₁To H level before proceeding to step S105.
Then, disconnection determination processing is performed. In this disconnection determination process,
For example, let the device 15 notify the central monitoring center
Do the job.

On the other hand, when the signal line L ₁ or L ₂ is not disconnected or not connected, the transistor Q ₄ is turned on, the input port I ₂ is at L level, the determination in step S103 is YES, and the process proceeds to step S106. . Check signal SG ₁ this time the light-emitting diode 25b lights up is input to the control section 21 of the gas leak alarm 2, the control unit 21 in response to this output an answer signal SG ₅ to the output port O _11. In step S106, the output port O
_{After 1 is set} to the H level, the process proceeds to step S107, and waits for the elapse of time T2 (for example, 0.9 seconds). When the time T2 has elapsed, the process proceeds to step S108, where CP
Output pulse counter (PC
Proceed to O) after the zero step S109 to the output port O ₂ to the L level to turn on the transistor Q _2. Incidentally, PCO is for counting the number of pulses outputted from the output port O _2.

Thereafter, the flow advances to step S110 to proceed to time T3.
(For example, 0.2 seconds) elapses. The process proceeds to step S111 when the time T3 has elapsed, determines where whether or not the input port I ₁ advances is incremented the PCO in step S112 is at the L level. Step output port O ₁ proceeds to step S114 when the determination is NO in step S112 after the H level S1
Proceeding to 15, it is determined whether the PCO count value is 3. If the determination in step S115 is NO, in step S116, the process waits until the time T3 has elapsed, and returns to step S109 to return to step S109.
To S116 are repeated, but the gas leak alarm 2
Since the phototransistor 27b in response to this when the answer signal SG ₅ from the control unit 21 is the output of the is turned on, the determination in any step S112 becomes to YES,
At this time, the process proceeds to step S113, where the input pulse counter (PCI) configured in the RAM in the CPU is incremented, and then the process proceeds to step S114.

In any case, if the PCO count value becomes 3 and the determination in step S115 becomes YES, the process proceeds to step S117 (FIG. 5), where it is determined whether the PCI count value is 0 or not. I do. When there is no answer signal SG _5, the input port I ₂ from becoming L level, since the increment of the PCI is not performed in step S113, the determination in step S117, the process proceeds to step S118 becomes YES, and the power failure here Perform determination processing. In this power outage determination process, the notification device 15 is not notified to the centralized monitoring center. In addition, when the outlet disconnection is determined before this, the power failure determination is not performed.

[0031] If the judgment at step S117 is NO, i.e., normally the answer signal SG ₅ when being delivered from the gas leak alarms 2 proceeds to step S119.
In step S119, it is determined whether the PCI count value is 2 or more. When the determination in step S119 is NO, that is, when the PCI count value is 1, there is an answer signal, and when a power failure determination has been made before that, it is considered that the power has been restored, and before that, the outlet disconnection determination is made. If so, it is considered that the outlet is plugged in, the process proceeds to step S120, the PCI is set to 0, and then the process proceeds to step S122. Further, the determination in step S119 is YE
In the case of S, that is, when the PCI value is 2 or more, the process proceeds to step S121 to set the PCI to 2, and then proceeds to step S122.

In step S122, time T4 (example
(For example, 1 second) elapses and proceeds to step S123.
And here is the output port O_TwoTo L level and Transis
TA Q _TwoTurn on. Then, proceed to step S124
Wait for the time T1 to elapse and proceed to step S125.
Only, here input port I₁Is at L level or not.
Set. If the determination in step S125 is NO,
That is, when the phototransistor 27b does not turn on,
Star Q_ThreeDoes not turn on, or the phototransistor 27
b turns on, but turns off after a certain period of time, and
Transistor Q_ThreeIs also turned off, step S1
Proceed to 26 to check whether the PCI count value is 1 or less.
judge. If the determination in step S126 is YES,
Proceed to step S127 to set PCI to 0 and then step
Proceed to S129 to output port O_TwoTo the H level.

[0033] In contrast, when the determination in step S125 is YES, i.e., when the transistor Q ₃ is turned ON the phototransistor 27b is turned on, is incremented the PCI proceeds to step S128 to step S129 Go to output port O ₂
To level. Then, the process proceeds to step S130 where P
It is determined whether the count value of the CI is 7 or more. If the determination is NO, the process returns to step S123 after waiting for the elapse of time T2 in step S131, and returns to step S123 until the determination in step S125 becomes NO. S123
To 125 and steps S128 to S131 are repeated.

If the determination in step S125 is YES,
The output port O_TwoWhen the level becomes L level,
Output port O of the control unit 21 of the leak alarm 2₁₁Alarm from
Signal SG₆Or outlet disconnect signal SG₇Is output
The phototransistor 27b is turned on or a signal
Line L₁And L_TwoInput port I ₁
Is at the L level. At this time, step S12
8 is repeated to increment the PCI.
Output port O_TwoInput port I even if₁Is L
Level and the PCI is 2 or more
If the determination in step S126 is NO, step S1
Proceed to 32 (FIG. 6). Step S125 has never been performed.
If the answer is YES, the process proceeds to steps S123 to S123.
S127 and S129 to 131 are repeated,
At the time when 60 seconds have elapsed since the start of the
Return to 01.

As described above, the control unit 2 of the gas leak alarm 2
Gas alarm signal SG ₆ or outlet missing signal S from 1
When advanced G ₇ is output as the count value of the PCI is 2 or more in accordance with this step S132, the process proceeds from here to the output port O ₂ to H level to step S133. In step S133, it is determined whether the PCI is 2-3 or not. If the determination is YES, the process proceeds to step S134 to set the PCI to 0, and then the process proceeds to step S13.
Proceeding to step 5 to perform outlet disconnection determination processing. In the outlet disconnection determination process, the central control center is notified via the notification device 15, and other tasks such as shutting off the gas shutoff valve 13 are performed. After the process in step S135, the process proceeds to step S136, and waits for the time T2 to elapse, and then returns to step S123.

[0036] When the determination in step S133 is NO, i.e., when the count value of PCI has been input gas alarm signal SG ₆ at 4-6, to 0 the count value of the PCO proceeds to step S137, then step Proceeding to S138, the count value of the PCI is set to 0. Then, step S1
Proceeds willing Wait for time T2 has elapsed 39 to step S140, the process proceeds where the output port O ₂ Wait for the willing time T1 elapsed since the L level to the step S141 to the step S142 . Step S1
42, whether the input port I ₁ is at the H level or not, that is, in step S140, the output port O 1
₁ to determine if the signal at the input port I ₁ when the L level is input, the step S1 when the determination in step S142 when the determination is YES in YES
Advances to 43, where the output port O ₂ proceeds from increments PCO to step S144 to H level. Thereafter, the process proceeds to step S145 to determine whether the PCO count value is 7 or more. If the determination is NO, the process returns to step S139 to return to steps S139 to S139.
Repeat 145.

[0037] In course of repeating the steps S139～S145, when the input port I ₁ is determined in step S142 becomes L level determination result is NO, step S1
Proceed to 46 determines whether the count value of the PCO is 3 or less, the judgment at step S146 into the re-monitoring operation of the input ports I ₁ returns to the step S128 when the YES. If the determination in step S146 is NO, that is, if the PCO count value is 4 to 6, step S146
Incrementing the PCI proceeds to 147, then the process proceeds to the output port O ₂ proceeds to step S148 after the H level in step S149 (Fig. 7). This step S
Proceeds Wait for the 149 time T2 has elapsed step S150, the wherein the output port O ₂ proceeds to step S151 after the L level. Proceeds at step S151 the time waiting for T1 elapses to step S152, the input ports I ₁ determines whether the L level here.

The determination in step S152 is incremented PCI proceeds to step S153 when YES, the then proceeds to output port O ₂ proceeds to step S154 after the H level in step S155. At step S155, it is determined whether or not the PCI count value is 7 or more.
149, and the above steps S149 to S155 are repeated. P output port O ₂ in step S150 when there is also the determination of step S152 in the L level of NO, the program proceeds as no signal input to the step S156
It is determined whether or not the count value of CI is 1 or less, and if the determination in step S156 is YES, the process proceeds to step S156.
Return to 127. On the other hand, when the determination in step S156 is NO, that is, when the PCI count value is 2 or more,
Proceeding to step S157, it is determined whether the PCI count value is 4-6. The determination in step S157 is N
When the value is O, that is, when the PCI count value is 2-3, the process returns to step S132, and finally, the process proceeds to step S1.
At 35, the outlet disconnection determination process is performed. If the judgment at step S157 is YES, i.e., subjected to gas leakage judgment processing proceeds to step S158 when the count value of the PCI is 4-6, Step output port O ₂ in the next step S159 after the H level S137 returning to, performs the input processing of the gas alarm signal SG _6. In the gas leak determination process, the valve drive circuit 14 controls the gas shutoff valve 1
In addition to shutting down the communication line 3, the communication device 15 performs a job of notifying the centralized monitoring center of the fact.

When the determinations in steps S130 and S155 are YES, that is, when the PCI count value is 7 or more, the flow proceeds to step S160 (FIG. 8) to set PCI to 0, and then proceeds to step S161 to determine whether or not water is wet. After performing the processing, the process returns to the step S136. In the water wetting determination process of step S161, the valve drive circuit 14
In addition to shutting off the gas shut-off valve 13, the notification device 15 performs a notification to the centralized monitoring center. When the determination in step S145 is YES and the PCO count value is 7 or more, the time elapses and the flow waits until the flowchart starts next.

As described above, the CPU forming the control unit 11 executes the signal line L ₁ by executing the flowchart.
The check signal periodically transmitted to, as a disconnection detecting means 11a for detecting a disconnection of the signal lines L _1, L ₂ depending on whether the check signal is returned via the signal line L _2, the sending cycle of the check signal during, and sends the voltage supply control signal at predetermined time intervals to the signal line L _2, a power failure of the gas leak alarm side by the number of the incoming voltage supply control signals back via the signal line L ₁ in accordance with the delivery And a control means 11c for controlling the gas shut-off valve 13 based on the detection by the two detection means.

Next, the CPU of the control unit 21 on the gas leak alarm 2 side performs processing as shown in the flowcharts of FIGS. The flowchart of FIG. 9 shows the processing for the input of the check signal SG _1, waits for the input port I ₁₂ In the first step S201 becomes L level. In other words, wait for the input of the check signal SG _1. Input port I ₁₂ proceeds Wait for the time T11 proceeds to step S202 becomes the L level, for example, 1.25 seconds passes to step S203, where the output port O ₁₁ to L level. Then step S20
4 and waits for the elapse of time T12, for example, 0.4 seconds, and then proceeds to step S205 where the output port O
₁₁ back from the H level to the step S201 waits for input of the next check signal SG _1. This operation, according to the input of the check signal SG _1, when the power is on, the output port O ₁₁ time after time T11 T1
The answer signal is output at L level for two.

The flowchart in Figure 10 is detected gas leakage by a signal from the gas leakage sensor 22 indicates the processing for the input of gas leakage alarm signal SG _12, the input port I ₁₁ becomes L level in the first step S211 that Wait for That is, waits for the input of gas leakage signal SG _11. When the input port I ₁₁ becomes L level step S2
Proceeding to 12, it is determined whether a time T13, for example, 35 seconds, has elapsed. If the input port I ₁₁ is continuously at the L level during the time T13, the determination in the step S212 is YES, and the process proceeds to the step S213, where the input port I ₁₁
Is determined to be still at the L level. This is when the decision is YES in step S213 to the output port O ₁₁ proceeds to step S214 to L level, then willing time T14 in step S215, the wait for example 5 seconds to elapse.

When the time T14 has elapsed, step S216 is performed.
Willing input port I ₁₁ to determines whether the L level. The determination in step S216 is repeatedly executed the steps S216~S218 from the output port O ₁₁ proceeds to step S217 to H level to willing time T14 to a step S218 elapses when YES, the input ports I ₁₁ Time T14 with L level
Has elapsed, the process returns to step S213 to restart the processing from step S213. Incidentally, when the determination in step S213 is NO, i.e., when the gas leak condition input port I ₁₁ is eliminated becomes H level, the output port O ₁₁ proceeds to step S219 to step S211 after the H level Return. If the determination in step S216 is NO, the process returns to step S211 via step S219.

With the above operation, the gas leak detection signal S
If G ₁₁ is continuously inputted over 35 seconds, the output ports O ₁₁
The in the 5 seconds L level every 5 seconds and outputs a gas alarm signal SG ₆ to gas leakage condition is cleared.

The flowchart of FIG. 11 shows the processing for the input of the outlet omission detection signal SG ₁₂ from outlet omission detection circuit 26, the input port I ₁₃ in the first step S221 is waiting for falls from H to L level Proceed to step S222 where the output port O
_{Set 11} to H level. Thereafter, the process proceeds to step S223, and waits for the elapse of time T15, for example, one second, and then proceeds to step S224. In step S224 the output ports O ₁₁ Time advances from the L level to step S225 T6, for example advances Wait for 2 seconds has elapsed in step S226, wherein the output port O ₁₁ from the H level returning to step S221 and waits for the next falling edge of the input port I _13. By the above operation, the outlet omission detection signal SG ₁₂ is inputted, the signal missing outlet to the output port O ₁₁ only once in two seconds L level S
And outputs the G _7. The power supply when the outlet is disconnected is provided by a backup power supply.

[0046] Incidentally, the flowcharts of FIGS. 9-11 as described above are executed in parallel, while waiting for the lapse of time T13 of 35 seconds at a gas leakage detection, the check signal SG ₁ is input Then, after the output of the answer signal, the state returns to the state of waiting for the elapse of the time T13. And after the time T13, the priority to the output of the gas alarm signal SG _6, the check signal is ignored. The outlet disconnection process is performed prior to other processes.

As described above, the CPU constituting the control unit 21 receives the check signal transmitted through the non-power failure signal lines L ₁ and L ₂ by executing the flowchart, and responds to this by receiving the check signal. As an answer transmission means 21a for transmitting an answer signal for turning on the first predetermined time, and as an alarm transmission means 21b for sending a gas alarm signal for turning on the phototransistor 27b in response to the detection of the gas leak for a second predetermined time. In response to detection of disconnection, the phototransistor 27b functions as outlet disconnection transmitting means 21c for transmitting an outlet disconnection signal for turning on the phototransistor 27b for a third fixed time.

[0048]

As described above, according to the present invention, the presence or absence of disconnection of a signal line can be detected by a check signal.
Also, since the time during which the switching means is turned on at the time of non-power failure answer, gas alarm, and outlet disconnection is changed on the gas leak alarm side, the voltage transmitted from the gas meter at a fixed time interval and returned to the gas meter via the switching means The number of supply control signals is changed according to each state and the short-circuit state of the signal line. With this number, not only the gas alarm, but also the power failure, the disconnection of the power outlet and the short-circuit of the signal line can be detected separately on the gas meter side. become.

[Brief description of the drawings]

FIG. 1 is a diagram showing a basic configuration of a gas alarm shutoff system according to the present invention.

FIG. 2 is a view showing one embodiment of a gas alarm shutoff system according to the present invention.

FIG. 3 is a timing chart showing a state of each unit in FIG. 2;

FIG. 4 is a flowchart illustrating a part of a process performed by a control unit of the gas meter in FIG. 2;

FIG. 5 is a flowchart showing another part of the processing performed by the control unit of the gas meter in FIG. 2;

FIG. 6 is a flowchart showing yet another part of the process performed by the control unit of the gas meter in FIG. 2;

FIG. 7 is a flowchart showing another part of the process performed by the control unit of the gas meter in FIG. 2;

8 is a flowchart showing still another part of the process performed by the control unit of the gas meter in FIG.

FIG. 9 is a flowchart showing one process performed by a control unit of the gas leak alarm in FIG. 2;

FIG. 10 is a flowchart showing another process performed by the control unit of the gas leak alarm in FIG. 2;

FIG. 11 is a flowchart showing yet another process performed by the control unit of the gas leak alarm in FIG. 2;

[Explanation of symbols]

1 meter 11a CPU (disconnection detecting means) 11b CPU (determination detecting means) 11c CPU (control means) 12 gas supply passage 13 the gas shut-off valve L _1, L ₂ signal line 2 gas leak alarms 21a CPU (answer transmission means) 21b CPU (alarm transmitting means) 21c CPU (outlet outlet transmitting means) 25b Light emitting diode (unidirectional element) 27b Phototransistor (switching means)

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-63-982 (JP, A) JP-A-6-111160 (JP, A) JP-A 4-111696 (JP, U) JP-A 2-111 95495 (JP, U) JP-A 3-119298 (JP, U) JP-A 61-112493 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G08B 21/00 G01R 31 / 04

Claims (1)

(57) [Claims] 1. A gas alarm shutoff system having a gas leak alarm and a gas meter interconnected by two signal lines, and a gas shutoff valve provided in a gas supply path, wherein the gas meter comprises the signal line Disconnection detecting means for periodically transmitting a check signal to one of them, and detecting a disconnection of the signal line depending on whether the check signal returns via the other signal line; A power supply control signal is transmitted to the other of the signal lines at regular time intervals, and the number of the voltage supply control signals returned via one of the signal lines in response to the transmission causes a power failure on the gas leak alarm device side. A discriminating detecting means for discriminating and detecting whether there is a gas leak, an outlet disconnection, or a short circuit of the signal line; and controlling the shutoff valve by detecting the disconnection detecting means and the discriminating detecting means. The gas leak alarm device, a one-way element that enables conduction from one of the signal lines to the other, and a switching device provided at an end of the signal line on the gas leak alarm device side. An answer transmitting means for receiving the check signal transmitted through the signal line when there is no power failure, and transmitting an answer signal for turning on the switching means for a first fixed time in response to the check signal; Alarm transmitting means for transmitting a gas alarm signal for turning on the switching means for a second fixed time in response thereto; and outlet disconnection for sending an outlet disconnection signal for turning on the switching means for a third fixed time in response to detection of disconnection of the outlet. A gas alarm shutoff system comprising: a transmission unit.