JPH06274775A - Gas alarm cut-off system - Google Patents

Abstract

PURPOSE:To provide a gas alarm cut-off system which can discriminate and detect not only the disconnection of a signal line and a gas alarm but a power interruption the detachment of a power plug socket and the short circuit of the signal line on the side of a gas meter. CONSTITUTION:A disconnection detector means 11a of a gas meter 1 detects the disconnection of a signal line L1 depending on whether the check signal sent to the line L1 is returned or not via a unidirectional element 25b and a signal line L2. Meanwhile a deciding/detecting means 11b detects a power interruption, the gas leakage, the detachment of a power plug socket and the short circuit of the signal line from the number of voltage supply control signals that are transmitted to the line L2 at a certain time interval and then returned via the line L1. In such a constitution, a control means 11 controls a cut-off valve 13. Then an answer transmitter means 21a, an alarm transmitter means 21b, and a plug socket detachment transmitter means 21c of a gas leakage alarm 2 turn on a switching means 27b respectively in different periods of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas leak alarm device, a gas meter and a gas alarm shutoff system having a gas shutoff valve, and more particularly, a gas leak alert device and a gas meter are connected by two signal lines. The present invention relates to a gas alarm shutoff system in which signals are transmitted and received between a gas leak alarm device and a gas meter through a signal line of a book.

[0002]

2. Description of the Related Art Conventionally, as an example of this type of system, a gas leak alarm is connected or not connected by determining whether a check signal sent from a gas meter through a signal line is returned through the signal line at regular intervals. The gas meter sends a pulse signal through the signal line at a short fixed period, and the pulse signal returns through the means for turning on in response to the gas leak detection provided on the gas leak alarm side. It has been proposed that a gas leak is detected by making a judgment. In the proposed device, when the signal line gets wet with water and short-circuits, the same state as when gas leakage occurs occurs, and the gas cutoff valve can be operated to cut off the gas supply.

As another example, a means for turning on the gas leak alarm when the power is on is provided on the gas leak alarm side, and the check signal sent from the gas meter is sent through the signal line when this means is off. There is proposed a device which can detect that the power is not turned on by not returning.

[0004]

However, in the above-mentioned conventional example, it is impossible to distinguish whether the power is not supplied due to a power failure or due to disconnection of an outlet. Therefore, in the case where the gas meter further notifies the centralized monitoring center, the gas meters in the area are simultaneously notified to the centralized monitoring center at the time of a power failure, and there is a possibility that the center cannot complete processing.

Further, since it is impossible to distinguish whether the gas cutoff is due to a gas leak or a short circuit of the signal line, there is a problem that it is not possible to take an appropriate measure after the gas cutoff.

Therefore, in view of the above-mentioned conventional problems, the present invention enables not only the disconnection of the signal line and the gas alarm but also the power failure, the disconnection of the power outlet and the short circuit of the signal line to be separately detected 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 cutoff system according to the present invention comprises:
As shown in the basic configuration diagram of FIG. 1, two signal lines L ₁ and L
_In a gas alarm cutoff system having a gas meter 1 and a gas leak alarm 2 connected to each other at 2, and a gas cutoff valve 13 provided in a gas supply path 12, the gas meter 1 checks one of the signal lines. A signal is sent periodically, and the disconnection detection means 11a detects the disconnection of the signal line depending on whether the check signal returns via the other signal line, and the disconnection detection means 11a detects the disconnection of the signal line. A voltage supply control signal is sent to the other of the signal lines at regular time intervals, and depending on the number of the voltage supply control signals returned via one of the signal lines, a power failure or gas leak on the gas leak alarm side A discrimination detection means 11b for discriminating and detecting whether the outlet is disconnected or the signal line is short-circuited, and the shutoff valve is controlled by the detection by the disconnection detection means and the discrimination detection means. The gas leak alarm 2 is provided at the end of the signal line on the gas leak alarm side, and a unidirectional element 25b that enables conduction from one of the signal lines to the other. Switching means 27b
And an answer sending means 21a for receiving the check signal sent through the signal line during non-power failure and sending an answer signal for turning on the switching means for a first fixed time in response to the check signal, and gas leak detection In response to this, an alarm transmitting means 21b for transmitting a gas alarm signal for turning on the switching means for a second fixed time, and an outlet disconnection signal for turning on the switching means for a third constant time in response to detection of disconnection of the outlet. It is characterized in that it is provided with an outlet disconnection transmitting means 21c.

[0008]

With the above construction, when the signal lines L ₁ and L ₂ are normally connected between the gas meter 1 and the gas leak alarm 2, the disconnection detecting means 11a of the gas meter 1 is connected to one of the signal lines 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.

Further, the discrimination detecting means 11b causes the check signal.
Of the other signal line L after the transmission of₂Constant to
The voltage supply control signal transmitted at time intervals is the signal line L.₁Over
And L ₂Is not short-circuited, and the gas leak alarm 2 side
When the switching means 27b of the
Signal line L₁Do not come back to the gas meter side via
Yes. However, the answer transmission means 21a connects the signal line during non-power failure.
Receives the check signal sent through and responds accordingly
To turn on the switching means for a first fixed time
A signal is sent out and the alarm transmission means 21b detects gas leak.
Gas for which the switching means is accordingly turned on for a second fixed time
Means 21c for sending an alarm signal and disconnecting the outlet
Switches the switching means in response to the detection of the unplugged outlet.
An outlet disconnection signal that turns on for a certain period of time 3 is sent.

Therefore, the discrimination detecting means 11b counts the voltage supply control signals returned via the _one signal line L ₁ in response to the transmission, and depending on the number, the power failure on the gas leak alarm side, the gas leak, the outlet. It is possible to detect whether the disconnection or the signal line is short-circuited, and the control means 11c detects the shut-off valve 13 by the detection by both the detection means 11a and 11b.
Can be appropriately controlled, and the necessity of reporting can be determined according to the detected content.

[0011]

Embodiments of the present invention will now be described with reference to the drawings.
To do. FIG. 2 shows an embodiment of the gas alarm shutoff system according to the present invention.
It is a figure showing an example, and in the figure, in the gas meter 1
The control unit 11 follows the predetermined control program.
Consists of operating microcomputer (CPU)
Output port O₁~ O_FourAnd input port I₁~ I ₃To
R having a control program (not shown)
Built-in RAM for storing OM and various data. output
Port O₁Is the check signal SG₁, Output port O₂Is electric
Source supply control signal SG₂, Output port O₃Is the cutoff signal SG
₃, And output port O_FourIs the notification signal SG_FourEach
Output. Input port I₁Is the answer signal SG_Five, Gas police
Report signal SG₆And outlet missing signal SG₇, Input port
To I₂Is the connection detection signal SG₈, And input port I₃Is
Cutoff state signal SG₉Respectively.

[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 By falling to the level, the transistor Q ₁ is biased in the ON state, and the DC power supply 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 By falling to the L level, the transistor Q ₂ is biased to the ON state, and the DC power supply voltage is supplied to the terminal T ₁₂ . The terminals T ₁₁ and T ₁₂ are respectively connected to the terminals T ₂₁ and T ₂₂ of the gas leak alarm 2 via _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 that drives a gas cutoff valve 13 provided in the gas supply path 12, and an output port O ₄ that outputs a notification signal SG ₄ is remotely monitored through a transmission path L ₃ such as a telephone line. It is connected to the reporting device 15 connected to the center.

The input port I ₁ has a collector for the 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 It is connected to the collector of the connected NPN transistor Q ₄ . The input port I ₃ is connected to a DC power source 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 device 2 uses a battery as a power source.
Unlike the gas meter 1 which rectifies and stabilizes the commercial AC power supply
DC power supply and backup power supply
Microcomputer that operates according to a control program
The control unit 21 includes a CPU (CPU).
This control unit 21 uses the input port I₁₁~ I₁₃And output port
O₁₁And has a control program (not shown)
Built-in ROM and RAM for storing various data
It Input port I₁₁Gas leak detection signal SG₁₁, Input port
Heart I₁₂Is the check signal SG₁, And input port I₁₃
Is an outlet detection signal SG₁₂Respectively.
Output port O₁₁Is the check signal SG₁According to the input of
Sensor signal SG_Five, Gas alarm signal SG₆And unplug
Signal SG ₇Are output respectively.

Gas leak detection signal SG₁₁Enter the input port
Heart I₁₁Is the detected gas concentration from the gas leak sensor 22.
The corresponding gas detection signal and the reference voltage of the reference voltage source 23 are compared.
It is connected to the output of the comparator 24 to
Outgoing signal SG₁₁The gas detection signal is larger than the reference voltage.
Then, it falls from H to L level. Check signal SG ₁
Input port I to input₁₂The collector is DC power
A phototransistor with a mitter connected to ground
Connected to the collector of the switch 25a. Photo transition
The star 25a has a terminal T_{twenty one}Anode, terminal T_{twenty two}On
And the light emitting diode 25b to which
The photo coupler 25 is constructed. Outlet unplugged
Detection signal SG₁₂Input port I to input₁₃Is, for example, real
No. 63-147795 or No. 63-1477
Outlet plug detection proposed by No. 96 etc.
It is connected to the output of circuit 26. Answer signal SG_Five,
Gas alarm signal SG₆And outlet missing signal SG₇Out
Output port O₁₁The anode is connected to the DC power supply
Connected to the cathode of the light emitting diode 27a
There is. The light emitting diode 27a has a terminal T_{twenty one}To the emitter,
Terminal T_{twenty two}The collectors are connected to
The photocoupler 27 is configured with the transistor 27b.
There is.

The outline of the operation of the system having the above configuration will be described below with reference to the waveform charts showing the states of the respective parts in FIG.
The control unit 11 of the gas meter 1 sets 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 , and accordingly, 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 the gas leak alarm 2 is normally connected via the signal lines L ₁ and L ₂ .

Further, a check signal SG from the control unit 11
₁That the light emitting diode 25b is turned on by sending
Therefore, the phototransistor 25a turns on and gas leaks.
Input port I of alarm device 2₁₂Falls from H to L level
This is the check signal SG ₁Input to the control unit 21 as
To be done. This check signal SG₁Depending on the input of
21 is an output port for, for example, 0.4 seconds after 1.25 seconds
O₁₁From H level to L level₁₁Send out
It This answer signal SG₁₁Light emitting diode
As shown in (c), the photo 27a lights up.
The transistor 27b is turned on.

On the other hand, the control section 11 controls the check signal S
Following the transmission of G ₁ , the output port O which is always at H level
₂ is once set to the L level for a predetermined period, and then, for example, one second later, for example, the L level is set to the L level several times at short intervals for a short period to turn on the transistor Q ₂ . At this time, if the phototransistor 27b is turned on, the current i ₂ flows and the transistor Q ₃ is turned on, so that the answer signal SG ₅ is input to the input port I ₁ . The control unit 11 repeatedly sends the voltage supply control signal SG ₂ by repeatedly setting the L level to the L level for a predetermined period every second until the next check signal is sent, and accordingly, the transistor Q _{2 is set} to (b). Turn on as shown.

The control unit 21 of the gas leak alarm 2 is
When a gas leak is detected by the signal from the gas leak sensor 22, the output port O ₁₁ thereof is set to L level for 5 seconds at an interval of 5 seconds, for example, and a gas alarm signal SG ₆ is sent to turn on the light emitting diode 27a at an interval of 5 seconds. As a result, the phototransistor 27b is turned on every 5 seconds as shown in (d). Further, when the outlet removal detection signal SG ₁₂ is input from the outlet removal detection circuit 26, the control unit 21 sets its output port O ₁₁ to the L level for, for example, 2 seconds and sends the outlet removal signal SG ₇ to output the light emitting diode 27a. Is turned on for 2 seconds, which turns on the phototransistor 27b for 2 seconds as shown in (e).

As described above, the transistor Q₂Turned on
At this time, if the phototransistor 27b is on,
Depending on the ON period of the₂,
Terminal T₁₂, Signal line L₂, Terminal T_{twenty two}, Phototransistor
27b, terminal T_{twenty one}, Signal line L ₁, Terminal T₁₁, Transis
Q₃Current to ground through the bias resistor of₂Flow
Transistor Q₃As shown in (g) to (i)
Will be This transistor Q₃Control part 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.

When the answer signal SG ₅ is input, the control unit 11 determines that the power is normally supplied and the gas leak alarm 2 is operating normally. When the answer signal SG ₅ is not input, the gas leak alarm is input. It is determined that power is not being supplied to the device 2 due to a power outage or unplugging. Further, it is judged that the gas leak is detected by the gas leak alarm device 2 by the input of the alarm signal SG ₆ , and the shutoff signal SG ₃ is output from the output port O ₃ in response to the detection, and the gas is supplied to the valve drive circuit 14. The shutoff valve 13 is driven to shut off. Further, it is determined that the absence of the answer signal SG ₅ is caused by the input of the outlet disconnection signal SG ₇ , which is caused by the disconnection of the outlet of the gas leak alarm device 2.

The phototransistor 27b is turned on.
Signal line L due to water wetting₁And L₂Is
When you are on the photo, as shown in (f),
The state where the transistor 27b is always on is formed.
Similarly, current flows through the short section,
As shown in (j), the transistor Q₂In sync with on
Transistor Q₃Will also turn on. This transition
Star Q₃Is turned on, the input port I of the control unit 11 is turned on.₁But
It falls from H to L level, and this becomes the water wetting signal.
It is input to the control unit 11. By inputting this water wet signal
Signal line L₁And L ₂Was shorted by water
To judge.

Based on the above judgment, the control unit 11
Is sent from the output port O ₄ when necessary, by the notification signal SG ₄
Is output and the transmission line L ₃ such as a telephone line is output to the notification device 15.
Through the centralized monitoring sensor to make a notification indicating that there is no connection, a gas alarm, a disconnection of an outlet, and water wetness.

The details of the operation of the system outlined above will be described below with reference to the flow charts of FIGS. 4 to 4 showing the processing performed by the CPU 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
U performs processing as shown in the flowcharts of FIGS. 4 to 8 started every 60 seconds, and the first step S10
At 1, the output port O _{1 is set} to L level, which turns on the transistor Q ₁ . Continuing step S10
At 2, wait for the time T1 (for example, 0.1 seconds) to elapse. When the time T1 has elapsed, the process proceeds to step S103, where it is determined whether the input port I ₂ is at L level.

The transistor Q₁When is on, signal
Line L₁Or L₂Is disconnected or not connected, the current i
₁Does not flow, so transistor Q_FourDoes not turn on
To I ₂Remains at the H level, and the judgment in step S103
The determination is NO and the process proceeds to step S104, where the output
Port O₁To H level before proceeding to step S105
Then, disconnection determination processing is performed. In this disconnection determination process, report
For example, by having the device 15 notify the centralized monitoring center of that fact.
Do the work.

On the other hand, when the signal line L ₁ or L ₂ is not broken or not connected, the transistor Q ₄ is turned on and the input port I ₂ becomes L level, the determination in step S103 becomes YES and the process proceeds to step S106. . At this time, the light emitting diode 25b is turned on and the check signal SG ₁ is input to the control unit 21 of the gas leak alarm device 2. In response to this, the control unit 21 outputs the answer signal SG ₅ to the output port O ₁₁ . In step S106, the output port O
_After setting ₁ to H level, the process proceeds to step S107, and waits until time T2 (for example, 0.9 seconds) elapses. When time T2 elapses, the process proceeds to step S108, where CP
Output pulse counter (PC
O) is set to 0, then the process proceeds to step S109, the output port O _{2 is set} to L level, and the transistor Q ₂ is turned on. The PCO is for counting the number of pulses output from the output port O ₂ .

After that, the routine proceeds to step S110, where time T3 is reached.
Wait for (eg 0.2 seconds) to elapse. When the time T3 has elapsed, the routine proceeds to step S111, where PCO is incremented and then the routine proceeds to step S112 where it is determined whether or not the input port I ₁ is at the L level. If the determination in step S112 is no, the process proceeds to step S114, where the output port O _{1 is set} to H level, and then step S1.
In step 15, it is determined whether the PCO count value is 3. When the determination in step S115 is NO, in step S116, the time T3 elapses, the process returns to step S109, and step S109 described above is performed.
The operation of S116 is repeated, but the gas leak alarm 2
When the answer signal SG ₅ from the control unit 21 is output, the phototransistor 27b is turned on accordingly, so that the determination in step S112 eventually becomes YES,
At this time, the process proceeds to step S113, where the input pulse counter (PCI) formed in the RAM in the CPU is incremented, and then the process proceeds to step S114.

In any case, when the PCO count value becomes 3 and the determination in step S115 becomes YES, the process proceeds to step S117 (FIG. 5), in which it is determined whether the PCI count value is 0 or not. To do. When there is no answer signal SG ₅ , the input port I ₂ does not go to the L level and PCI is not incremented in step S113, so the determination in step S117 becomes YES and the process proceeds to step S118, where a power failure occurs. Judgment processing is performed. In this power failure determination process, the notification device 15 is not made to notify the centralized monitoring center. In addition, when it is determined that the outlet is unplugged before this, the power failure determination is not performed.

When the determination in step S117 is NO, that is, when the answer signal SG ₅ is normally sent from the gas leak alarm device 2, the process 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 the power failure determination is performed before that, it is considered that the power is restored, and the outlet disconnection determination is performed before that. If it is, it is regarded as plugging in the outlet, the process proceeds to step S120, the PCI is set to 0, and then the process proceeds to step S122. In addition, the determination in step S119 is YE.
When S, that is, when PCI is a value of 2 or more, the process proceeds to step S121, the PCI is set to 2, and then the process proceeds to step S122.

In step S122, time T4 (example
Wait for 1 second) and proceed to step S123.
Output port O here₂To L level
Q ₂Turn on. Then proceed to step S124
Wait for the time T1 to elapse and then proceed to step S125.
Here, input port I₁Determine whether is at L level
Set. If the determination in step S125 is no,
That is, the phototransistor 27b does not turn on
Star Q₃Does not turn on or the phototransistor 27
b turned on, but turned off after a certain period of time.
Langista Q₃Is also turned off, step S1
Go to step 26 and check if the PCI count value is 1 or less.
judge. If the determination in step S126 is yes,
Go to step S127 and set PCI to 0, then step
Proceed to S129 to output port O₂To H level.

On the other hand, when the determination in step S125 is YES, that is, when the phototransistor 27b is turned on and the transistor Q ₃ is turned on, the process proceeds to step S128, PCI is incremented, and then the process proceeds to step S129. Go to output port O ₂ to H
To level. After that, the process proceeds to step S130, where P
It is determined whether or not the CI count value is 7 or more. If this determination is NO, the process returns to step S123 after waiting for the time T2 to elapse in step S131, and steps are performed until the determination in step S125 becomes NO. S123
~ 125 and steps S128 to S131 are repeated.

If the determination in step S125 is YES.
Output port O₂When the L level becomes
Output port O of the control unit 21 of the leak detector 2₁₁Alarm from
Signal SG₆Or outlet missing signal SG₇Is output
The phototransistor 27b is turned on or a signal
Line L₁And L₂Input port I due to short circuit ₁
Is at the L level, and at this time, step S12
8 is repeatedly executed to increment the PCI.
Output port O₂Input port I₁Is L
It does not reach the level, and the PCI is 2 or more
If the determination in step S126 is no, step S1
32 (FIG. 6). In addition, step S125 has never been
If not YES, step S123-
Repeat S127, S129-131
60 seconds after the start of
Return to 01.

As described above, the control unit 2 of the gas leak alarm device 2
Gas alarm signal SG ₆ from 1 or outlet disconnect signal S
When G ₇ is output and the count value of PCI becomes 2 or more in response to this and the process proceeds to step S132, the output port O _{2 is set} to H level here and then the process proceeds to step S133. In step S133, it is determined whether or not the PCI is 2-3, and if the determination is YES, the process proceeds to step S134 to set the PCI to 0, and then step S13.
Proceeding to step 5, the outlet disconnection determination process is performed. In this outlet disconnection determination process, in addition to notifying the central monitoring center via the notification device 15, the gas shutoff valve 13 is shut off. After the processing of step S135, the process proceeds to step S136, 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 In step S138, the PCI count value is set to zero. Then step S1
After proceeding to step 39 and waiting for the time T2 to elapse, the operation proceeds to step S140, where the output port O _{2 is set} to the L level and then the operation proceeds to step S141 to wait for the time T1 to elapse and then the operation proceeds to step S142. . Step S1
At 42, whether or not the input port I ₁ is at H level, that is, at step S140, the output port O
_{When 1 is set} to the L level, it is determined whether or not a signal is input to the input port I _1. When the determination is YES, the step S142 is YES, and when the determination is YES, the step S1 is performed.
In step 43, PCO is incremented here, and then in step S144, the output port O _{2 is set} to H level. After that, the process proceeds to step S145, and it is determined whether or not the PCO count value is 7 or more. When the determination is NO, the process returns to step S139 and steps S139 to S139.
Repeat 145.

In the process of repeating steps S139 to S145, when the input port I ₁ becomes L level and the determination in step S142 becomes NO, step S1
In step 46, it is determined whether or not the PCO count value is 3 or less. When the determination in step S146 is YES, the process returns to step S128 to start the re-monitoring operation for the input port I ₁ . When the determination in step S146 is NO, that is, when the PCO count value is 4 to 6, step S146 is performed.
In step 147, the PCI is incremented, then in step S148, the output port O _{2 is set} to the H level, and then the process proceeds to step S149 (FIG. 7). This step S
At 149, after the time T2 has elapsed, the process proceeds to step S150, where the output port O ₂ is set to the L level, and then the process proceeds to step S151. In step S151, after the time T1 has elapsed, the process proceeds to step S152, in which it is determined whether the input port I ₁ is at the L level.

When the determination in step S152 is YES, the process proceeds to step S153 to increment the PCI, and then the process proceeds to step S154 to set the output port O ₂ to H level and then proceeds to step S155. In step S155, it is determined whether or not the count value of PCI is 7 or more. If the determination is NO, the above step S155 is performed.
Returning to 149, the above steps S149 to S155 are repeated. Even if the output port O _{2 is set} to the L level in step S150, if the determination in step S152 is NO, it is determined that there is no signal input and the process proceeds to step S156.
It is determined whether or not the CI count value is 1 or less, and when the determination in step S156 is YES, the above step S
Return to 127. On the other hand, when the determination in step S156 is NO, that is, when the count value of PCI is 2 or more,
In step S157, it is determined whether the PCI count value is 4 to 6. If the determination in step S157 is N
When it is O, that is, when the count value of PCI is 2 to 3, the process returns to step S132, and finally step S1.
At 35, the outlet disconnection determination process is performed. When the determination in step S157 is YES, that is, when the PCI count value is 4 to 6, the process proceeds to step S158 to perform the gas leakage determination process, and the output port O _{2 is set} to the H level in the next step S159, and then the above step S137. Then, the gas alarm signal SG ₆ is input. In the gas leakage determination process, the gas shutoff valve 1 is set in the valve drive circuit 14.
In addition to shutting off 3, the notification device 15 performs the work of notifying the centralized monitoring center to that effect.

When the determinations at steps S130 and S155 are YES, that is, when the PCI count value is 7 or more, the process proceeds to step S160 (FIG. 8) to set the PCI to 0, and then the process proceeds to step S161 to determine the wetness determination. After performing the process, the process returns to step S136. In addition, 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 reporting device 15 also performs such work as making a notification to that effect to the centralized monitoring center. When the determination in step S145 is YES, and when the PCO count value is 7 or more, the process waits until the time elapses and the flowchart starts next.

As described above, the CPU constituting the control section 11 executes the flow chart to execute the signal line L ₁
A check signal is sent periodically to the check signal, and the check signal sending cycle is used as the disconnection detecting means 11a for detecting the disconnection of the signal lines L ₁ and L ₂ depending on whether the check signal returns via the signal line L _2. During this period, a voltage supply control signal is sent to the signal line L ₂ at regular time intervals, and in response to this sending, the number of voltage supply control signals returned via the signal line L ₁ causes a power failure on the gas leak alarm side. , And a control means 11c for controlling the gas cutoff valve 13 by the detection by both the detection means and the discrimination detection means 11b for discriminating and detecting the gas leak, the disconnection of the outlet and the short circuit of the signal line.

Next, the CPU of the control unit 21 on the side of the gas leak alarm 2 performs the processes shown in the flowcharts of FIGS. 9 to 11 which are executed in parallel. The flowchart of FIG. 9 shows the processing for the input of the check signal SG ₁ , and waits for the input port I _{12 to} go to the L level in the first step S201. That is, the input of the check signal SG ₁ is awaited. When the input port I ₁₂ becomes L level, the process proceeds to step S202, waits for time T11, for example, 1.25 seconds, and then proceeds to step S203, at which the output port O _{11 is set} to L level. Then step S20
4 and waits for time T12, eg, 0.4 seconds, to proceed to step S205, where the output port O
_After setting ₁₁ to the H level, the process returns to step S201 and waits for the next check signal SG ₁ to be input. By this operation, when the power is turned on in response to the input of the check signal SG ₁ , the output port O ₁₁ is turned on after the time T11 at the time T1.
During 2 the L level is set and the answer signal is output.

The flow chart of FIG. 10 shows the processing for the input of the gas leak alarm signal SG _{12 when} the gas leak is detected by the signal from the gas leak sensor 22, and the input port I ₁₁ becomes L level in the first step S211. Wait for That is, it waits for the input of the gas leak signal SG ₁₁ . When the input port I ₁₁ becomes L level, step S2
In step 12, it is determined whether time T13, for example, 35 seconds has elapsed. If the input port I ₁₁ is continuously at the L level for the time T13, the determination in step S212 is YES and the process proceeds to step S213, where the input port I _{11 is}
Is still at the L level. When the determination in step S213 is YES, the process proceeds to step S214, the output port O _{11 is set} to L level, and then the process proceeds to step S215 to wait until time T14, for example, 5 seconds has elapsed.

When time T14 elapses, step S216
Then, the process proceeds to step S30 to determine whether the input port I ₁₁ is at L level. When the determination in step S216 is YES, the process proceeds to step S217 to set the output port O ₁₁ to the H level, and then proceeds to step S218 to repeatedly execute the above steps S216 to S218 until the time T14 elapses, and the input port I ₁₁ Time T14 with L level
When elapses, the process returns to step S213 to restart the process from step S213. When the determination in step S213 is NO, that is, when the gas leakage state is eliminated and the input port I ₁₁ becomes H level, the process proceeds to step S219, where the output port O _{11 is set} to H level, and then the above step S211 is performed. Return. If the determination in step S216 is no, the process returns to step S211 via step S219.

By the above operation, the gas leak detection signal S
When G ₁₁ is input for 35 seconds or longer, output port O ₁₁
Is set to the L level for 5 seconds every 5 seconds, and the gas alarm signal SG ₆ is output until the gas leakage state is eliminated.

The flowchart of FIG. 11 shows the processing for the input of the outlet removal detection signal SG ₁₂ from the outlet removal detection circuit 26, and waits for the input port I ₁₃ to fall from the H level to the L level in the first step S221. Proceed to step S222, where output port O
_{Set 11} to H level. After that, the routine proceeds to step S223, waits for time T15, for example, one second, to elapse, and then proceeds to step S224. In step S224, the output port O _{11 is set} to the L level, then the process proceeds to step S225, waits for the time T6, for example, 2 seconds, and then the process proceeds to step S226, where the output port O _{11 is set} to the H level and then the above. It returns to step S221 and waits for the next fall of the input port I ₁₃ . By the above operation, when the outlet disconnection detection signal SG ₁₂ is input, the output port O _{11 is set} to L level for 2 seconds only once, and the outlet disconnection signal S is set.
Output G ₇ . The power supply when the outlet is unplugged is provided by the backup power supply.

Although the flowcharts of FIGS. 9 to 11 are executed in parallel as described above, the check signal SG ₁ is input while waiting for the elapse of the time T13 of 35 seconds at the time of gas leak detection. In the case of, when the answer signal is output, the state returns to the waiting state for 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. Further, the processing for disconnecting the outlet is performed prior to other processing.

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

[0048]

As described above, according to the present invention, it is possible to detect the presence or absence of disconnection of the signal line by the check signal.
In addition, the gas leak alarm side changes the time to turn on the switching means at the time of uninterrupted answer, gas alarm, and disconnection of outlet, so the voltage sent from the gas meter at fixed time intervals and returned to the gas meter via the switching means. The number of supply control signals will change depending on each state and the short-circuit state of the signal line, and by this number, not only gas alarm but also power failure, disconnection of power outlet and short-circuit of signal line can be detected separately on the gas meter side. become.

[Brief description of drawings]

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

FIG. 2 is a diagram showing an embodiment of a gas alarm cutoff system according to the present invention.

FIG. 3 is a timing chart showing a state of each part in FIG.

FIG. 4 is a flowchart showing a part of processing performed by a control unit of the gas meter in FIG.

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

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

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

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

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

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

FIG. 11 is a flowchart showing still another processing performed by the control unit of the gas leak alarm in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 gas meter 11a CPU (disconnection detection means) 11b CPU (discrimination detection means) 11c CPU (control means) 12 gas supply path 13 gas cutoff valves L ₁ and L ₂ signal lines 2 gas leak alarm 21a CPU (answer transmission means) 21b CPU (alarm transmission means) 21c CPU (outlet disconnection transmission means) 25b Light emitting diode (unidirectional element) 27b Phototransistor (switching means)

Claims (1)

[Claims] 1. A gas alarm cutoff system having a gas leak alarm and a gas meter mutually connected by two signal lines, and a gas cutoff valve provided in a gas supply path, wherein the gas meter is the signal line. A disconnection detecting unit that periodically transmits a check signal to one of the two, and detects a disconnection of the signal line depending on whether the check signal returns via the other signal line; and a disconnection period of the check signal. In addition, a voltage supply control signal is sent 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 sending causes a power failure on the gas leak alarm side. Discrimination detection means for discriminating and detecting whether gas leakage, outlet disconnection, or short circuit of the signal line, and controlling the shutoff valve by detection by the disconnection detection means and the discrimination detection means The gas leak alarm is a unidirectional element that enables conduction from one of the signal lines to the other, and a switching unit provided at the gas leak alarm side end of the signal line. And an answer transmitting means for receiving the check signal sent through the signal line during non-power failure and sending an answer signal for turning on the switching means for a first fixed time in response to the check signal, and for detecting a gas leak. In response, an alarm transmitting means for transmitting a gas alarm signal for turning on the switching means for a second constant time, and an outlet disconnection for transmitting an outlet disconnection signal for turning on the switching means for a third constant time in response to detection of disconnection of the outlet. A gas alarm cutoff system comprising: a transmission means.