JP3502169B2 - Wireless communication 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 wireless communication system such as an alarm interlocking wireless receiver attached to a gas meter.

[0002]

2. Description of the Related Art Conventionally, a detector for detecting a gas leak or the like is provided in a room, a radio transmitter is attached to the detector, a radio receiver is attached to a gas microcomputer meter, and when the detector detects a gas leak or the like, A system has been developed in which an alarm signal is sent wirelessly and a gas microcomputer meter shuts off the gas.

Further, some alarm receiver interlocking radio receivers are provided when communication is disabled after confirmation of the start of communication of an alarm signal.
Some have a function of issuing a gas cutoff command to a gas meter.

[0004]

However, after the wireless receiver is installed in an actual environment and the communication environment around it deteriorates, even if an alarm signal is issued, it may not be able to be received correctly. was there. For example, in the alarm receiver interlocking radio receiver attached to the gas meter, when the reception environment deteriorates, even if an alarm signal is issued from the transmitter, it cannot be received and continues to be supplied when the gas supply should be cut off, There is a risk of an accident. The present invention has been made in view of such a problem, and an object thereof is to periodically determine whether or not the radio wave environment of the installation location of the wireless receiver has deteriorated, and to say that the radio wave environment has deteriorated. When it is determined, as a fail-safe function, it is necessary to take measures for safety. For example, an alarm interlocking radio receiver attached to a gas meter shuts off gas supply when it is determined that the radio wave environment has deteriorated.

[0005]

In order to achieve the above-mentioned object, the present invention provides a detector for detecting an abnormal condition, a radio transmitter connected to the detector, a radio receiver, and the radio. A wireless communication system comprising a terminal connected to a receiver, and when the detector detects an abnormality, an alarm signal is sent from the wireless transmitter to the wireless receiver, and gas is cut off at the terminal. In the above, the wireless receiver intermittently performs carrier sense, detects the carrier, and determines the number of times that it is determined that there is unintended communication that is not communication addressed to itself.
The wireless communication system, wherein the terminal shuts off gas when the accumulated value exceeds a threshold value .

[0006]

In the wireless communication system according to the gas detector of the present invention, when the detector detects an abnormality and an alarm signal is transmitted as a radio wave through the transmitter and the antenna, the alarm signal is transmitted to the antenna of the receiver. It is a system for receiving gas with a terminal such as a gas microcomputer meter to shut off gas, but there is a danger that an alarm signal will not be received if the radio wave environment is bad, so the receiver intermittently carries out carrier sense. The quality of the radio wave environment is judged according to a predetermined standard. When the radio wave environment is lower than a predetermined standard, it is judged that there is a risk that the radio wave for transmitting the alarm signal cannot be received even if the radio wave is transmitted, and the terminal is operated to shut off the gas.

As a criterion for judging the quality of the radio wave environment, data such as the number of times the carrier is not detected when the carrier sense is performed, the number of times the carrier is detected but the communication is not addressed to itself, and the like To use.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows a wireless communication system 1 according to the present invention.
2 is a block diagram illustrating the configuration of FIG. When any abnormality is detected by the detector 3 such as a city gas alarm, a predetermined alarm signal is sent from the detector 3 to the transmitter 5, and the transmitter 5
Sends an alarm signal as a radio wave through the antenna 7.
When the antenna 11 of the receiver 9 receives the radio wave transmitting the alarm signal, the terminal 13 performs a predetermined operation.
The predetermined operation on the terminal 13 includes shutting off gas by a gas supply shutoff device of a gas microcomputer meter, driving an alarm device, and the like.

In the wireless communication system 1 of the present invention, the receiver 9 intermittently carries out carrier sensing, and based on data such as the number of times a carrier is detected and the number of times communication is not addressed to itself, the receiver 9 The quality of the radio wave environment in which is placed is determined. If the radio wave environment determined by the predetermined method is a bad radio wave environment that is equal to or lower than the predetermined standard, it is determined that there is a danger that the signal cannot be received even if the radio wave that transmits the alarm signal is transmitted, and For avoidance, perform operations such as shutting off gas.

FIG. 2 is a flowchart showing the operation of the wireless communication system 1. The receiver 9 performs carrier sense by intermittent operation (step 201). Next, it is determined whether or not there is a carrier (step 202), and if there is a carrier, it is determined whether or not the communication is addressed to itself (step 203). When it is determined in step 203 that the communication is addressed to itself, it is determined whether or not it is an alarm signal (step 204).

If it is determined in step 204 that the signal is not an alarm signal, a counter C _OFF indicating the integrated value in the case of no carrier integrated in step 206, step 20
The counter C _F indicating the integrated value in the case where there is a carrier accumulated in step 7 but it is determined that the communication is not addressed to itself and there is communication other than the purpose, and all counters related to each determination method shown in FIGS. 3 to 6. Clear (step 205) and wait for the next intermittent operation timing. If it is not confirmed in step 202 that there is a carrier, the counter C _OFF indicating the no-carrier integrated value is incremented by 1 (step 20
6) The quality of the radio wave environment is judged by a predetermined method to judge whether the gas supply should be shut off, and it is judged whether or not various integrated values used for the judgment can be cleared (step 20).
8).

[0012] In step 203, if it is determined not to be communication addressed to itself increases the counter C _F indicating out-of-target communication Yes accumulated value by 1 (step 207), the quality of the radio wave environment in a predetermined manner It is determined whether or not the gas supply should be shut off, and whether or not the various integrated values used for the determination can be cleared is determined (step 208).

A large value of C _F means that there is a large number of times that it is judged that there is communication other than the intended communication that has a carrier but is not addressed to itself, and a radio wave having the same frequency as the radio wave for transmitting the alarm signal. Is frequently present due to an event other than the alarm signal. In other words, even if an alarm signal is emitted due to an accident such as a gas leak, there are radio waves other than the alarm signal that have the same frequency as the alarm signal around the receiver, and the noise interferes with the alarm signal. There is a high possibility that Therefore, if the value of C _F is large, it is necessary to avoid danger.

If it is not determined in step 208 that the gas microcomputer meter should be shut off, the timing of the next intermittent operation carrier sense is awaited.

When it is determined in step 204 that the signal is an alarm signal and when it is determined in step 208 that the gas microcomputer meter should be shut off, the gas microcomputer meter shuts off the gas supply (step 209). .

There are various possible algorithms for determining whether or not the gas supply should be interrupted by the gas microcomputer meter in step 208 of FIG. 2, but four examples will be described below.

FIG. 3 is a flow chart showing the first method of the radio wave environment judging method in the radio communication system 1. The first method is a method in which the gas supply is cut off after K times are repeated after repeating the case of unintended communication in which it is determined that there is a carrier but communication is not addressed to itself at each carrier sense. In order to carry out the first method, for example, it is determined whether or not the counter C _{F, which} is incremented by 1 when the case of non-target communication is repeated, is equal to or more than a threshold value K (step 301), and C _F Is greater than or equal to the threshold value K, it is determined that the radio wave environment is bad, and the process returns to step 209 in FIG. 2 to cut off the gas supply.

At step 301, the counter C _F is set to the threshold K.
If it is less than the above, it is determined that the radio wave environment is not bad, and it is determined that there is unintended communication depending on whether or not the counter C _OFF, which indicates the number of times the carrier is determined to have no carrier, is 1 or more. It is determined whether or not the cases occur continuously (step 302). actually,
C _OFF takes only a value of 0 (zero) or 1.

That is, C _OFF is set to 1 in step 302 in this carrier sense in step 206 of FIG.
This is because the integrated value C _OFF when there is no carrier has increased by 1, and when it is determined that there is unintended communication at this point, there is no continuity of C _F. Therefore, the value of C _F is cleared to 0 (zero), and at the same time, the value of C _OFF is cleared to 0 (zero) (step 303).

Further, C _OFF is 0 in step 302 because it is determined in the present carrier sense that there is a carrier in step 202 of FIG. 2 and it is determined in step 203 that the communication is not addressed to itself. Therefore, C
_{The OFF} value is left at 0 (zero), the C _F value is also increased by 1 in step 207, and the process returns to step 201 in FIG.

If there is unintended communication in the next carrier sense, the value of C _F is integrated. If there is no carrier in the next carrier sense, the value of C _F is cleared to 0 (zero), and at the same time. , C _OFF are also cleared to 0 (zero) (step 303) and the process returns to step 201 of FIG.

FIG. 4 is a flow chart showing a second method of the radio wave environment judging method in the radio communication system 1.
The counter B is incremented each time the counter C _{F, which} is incremented when it is determined that there is a carrier but not the communication destined for itself but unintended communication, is incremented (step 401). In addition, the counter B is decremented each time the counter C _OFF, which indicates the number of times of no carrier determination at the carrier sense timing, increases (step 402).

In step 402, for example, in each carrier sense, a state without carrier and a state with unintended communication are alternately repeated at a frequency of about 50% in time, that is, an alarm signal is transmitted. In this case, it is assumed that there is about 50% possibility that the data can be normally received. If only step 401 does not include step 402, the counter B will increase and increase to the threshold value L or more immediately, but this will cut off the gas supply although it is not necessary. However, if the carrier-free state is 50% or more, the counter B does not exceed the threshold L, and it is determined that the radio wave environment is good.

Next, it is determined whether or not the counter B is equal to or greater than the threshold L (step 403). If the counter B is equal to or greater than the threshold L, it is determined that the radio wave environment is bad, and the process returns to step 209 in FIG. Shut off the gas supply.

In step 403, when the counter B is less than the threshold value L, the number of times the carrier sense was performed but the communication was not addressed to itself (C _F + C
It is determined whether or not ( _OFF ) is greater than or _equal to the threshold value M (step 404). If C _F + C _OFF is greater than or equal to M in step 404, the values of the flag counter C _F , the flag counter C _OFF, and the counter B are cleared to 0.
(Zero) (step 405) and step 20 in FIG.
Return to 1. If C _F + C _OFF is less than M in step 404, the process directly returns to step 201 in FIG.

Determination of step 404 and step 40
The reason why the process of 5 is necessary is, for example, communication outside the purpose ( _CF )
Occurs with a probability of 50.001%, if the value of the counter B is continuously accumulated for a certain period of time or longer, the counter B will eventually reach the threshold value L or more, but C _F , C _OFF and clear counter B to 0
It means to set it to (zero) and avoid meaningless integration for a long time. By adjusting the threshold value M, this period can be set arbitrarily.

FIG. 5 is a flow chart showing a third method of the radio wave environment judging method in the radio communication system 1.
The third method uses C instead of the counter B of the second method.
This is a determination method using a counter C in which _F and C _OFF are respectively weighted.

First, the counter C is incremented by i each time the counter C _{F which} is incremented when there is a carrier but communication other than the purpose determined that the communication is not addressed to itself (step 501). In addition, a counter C indicating the number of times of no carrier determination at the carrier sense timing.
Each time _OFF increases, counter C is decremented by j (step 502).

At this time, if i is set to 1 and j is set to 3, for example, the state (C _F ) with unintended communication is 75% in terms of time,
If the carrier-free state (C _OFF ) is 25%, the counter C is deducted to 0 (zero) and the threshold N
The above does not occur and the gas supply is continued. If the status of non-target communication exceeds 75%, counter C
Will eventually exceed the threshold value N, and it will be judged that the radio wave environment is bad, and the gas will be shut off. Non-target communication status is 75
If the degree of exceeding% is small, the time until the threshold N is exceeded becomes long, and if the degree of communication with non-target communication exceeds 75%, the time until the threshold N is exceeded becomes short. Depending on the situation, it is possible to take a gas shutoff procedure at an appropriate timing. Further, by appropriately adjusting the values of i and j, it becomes possible to finely adjust the judgment standard of the radio wave environment.

Next, it is determined whether or not the counter C is equal to or more than the threshold value N (step 503). If the counter C is equal to or more than the threshold value N, it is determined that the radio wave environment is bad, and the process returns to step 209 in FIG. Shut off the gas supply.

When the counter C is less than the threshold value N in step 503, it is determined whether C _F + C _OFF is greater than or equal to the threshold value P (step 504). Step 504
If C _F + C _OFF is P or more, C _F , C
The values of _OFF and the counter C are cleared to 0 (zero) (step 505), and the process returns to step 201 of FIG.
If C _F + C _OFF is less than P in step 504, the process directly returns to step 201 in FIG.

The reason why steps 504 and 505 in FIG. 5 are necessary is that steps 404 and 405 in FIG.
The reason is the same as above.

FIG. 6 is a flow chart showing a fourth method of the radio wave environment judging method in the radio communication system 1.
In the fourth method, in addition to the cumulative values of C _OFF and C _F , the cumulative number of consecutive times of C _OFF and C _F is used as a criterion. It should be noted that step 601 is a determination process required because the following process is different depending on whether it is C _OFF or C _F in the current carrier sense, but in reality, in step 203 and step 204 of FIG. The content has already been determined.

Step 601 (step 203 in FIG. 2)
In the case were C _F is in this carrier sense, C _F is up counter D to each successive Q times (step 602). Even after up counter D placed without clearing the integrated value of the continuous number of C _F unless C _F is continuously generated, continuously count integrated value of C _F is whether it is R times When the determination is made (step 603) and the cumulative value of C _F consecutive times has continued R times, it is determined that the radio wave environment is bad, and the flow returns to step 209 in FIG. 2 to shut off the gas supply. In step 603, if the cumulative number of consecutive times of C _F does not reach R times, it is determined whether or not the counter D indicating the number of times C _F has continued Q times or more has reached a predetermined value S or more ( Step 604). In step 604, when the counter D becomes equal to or more than the predetermined value S, it is determined that the radio wave environment is bad, and the process returns to step 209 in FIG. 2 to cut off the gas supply.

When the counter D is less than the predetermined value S in step 604, it is determined that the radio wave environment is not bad at that time. Next, it is determined whether or not the sum of the cumulative values of C _OFF and C _F is equal to or greater than a predetermined value U (step 606).

Step 601 (step 202 in FIG. 2)
In the case were _{C OFF} in this carrier _sense, each time _{the C OFF} is continuous T times, the counter is cleared D (step 605). Whether or not the total number of consecutive C _OFF and C _F is greater than or equal to a predetermined value U is determined in step 606 regardless of whether the number of continuous C _OFF is less than T or more than T. judge.

The reason why steps 606 and 607 in FIG. 6 are necessary is that steps 404 and 405 in FIG. 4 are necessary.
The reason is the same as above.

The thresholds L, M, N, which are used for judging the quality of the electrical environment in each of the first to fourth methods,
By making it possible to easily change the numerical values of P, Q, R, S, T and the up / down coefficients i, j of the counter C of the third method by tuning, it is possible to more appropriately determine the radio wave environment. It is possible.

As described above, according to the present embodiment, the quality of the radio wave environment in which the receiver 9 is placed is determined every time carrier sense is performed, and when it is determined that the radio wave environment is deteriorated,
It is possible to provide a wireless communication system that cuts off gas supply at an appropriate timing.

..

As described above in detail, according to the present invention, it is possible to provide a wireless communication system that shuts off the gas supply when it is determined that the radio wave environment has deteriorated.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a wireless communication system 1.

FIG. 2 is a flowchart showing the operation of the wireless communication system 1.

FIG. 3 is a flowchart showing an example (first method) of a radio wave environment determination method.

FIG. 4 is a flowchart showing an example (second method) of a radio wave environment determination method.

FIG. 5 is a flowchart showing an example (third method) of a radio wave environment determination method.

FIG. 6 is a flowchart showing an example (fourth method) of a radio wave environment determination method.

[Explanation of symbols]

1 ... Wireless communication system 3 ... Detector 5 ......... Transmitter 7 ... Antenna 9 ... Receiver 11 ... Antenna 13 ......... Terminal

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) G08B 19/00-21/24 G08B 23/00-31/00

Claims (4)

(57) [Claims] 1. A detector for detecting an abnormal state, a wireless transmitter connected to the detector, a wireless receiver, and a terminal connected to the wireless receiver, wherein the detector is abnormal. In the wireless communication system in which an alarm signal is sent from the wireless transmitter to the wireless receiver when the gas is cut off in the terminal, the wireless receiver intermittently performs carrier sense to detect the carrier. Detected, and communication other than the intended one is not addressed to itself
The wireless communication system, wherein the terminal shuts off gas when an integrated value based on the determined number of times exceeds a threshold value . 2. The integrated value is determined to have communication other than the purpose.
Contracts characterized by being accumulated according to the continuity of
The wireless communication system according to claim 1. 3. The integrated value is determined to have communication other than the purpose.
Depending on the ratio between the case where it is judged that there is no carrier and the case where it is judged that there is no carrier
The radio according to claim 1, wherein the radio is accumulated
Communications system. 4. The integrated value is determined to have communication other than the purpose.
If the first continuous count integrated value according to the continuity of the
The second continuity according to the continuity when it is judged that there is no rear
It is characterized in that it is accumulated according to the ratio with the accumulated value of the number of times
The wireless communication system according to claim 1.