JP2000286991A - Radio metering system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a communication success rate even at a condition that received power becomes low by controlling the maxim number of times of retransmission of data when the initial transmission from a slave machine to a master machine is failed. SOLUTION: When a carrier detection means 41a detects a start message from a master machine to a slave machine 40, a return means 41b returns a response message to the master machine. A setting operation part 48 sets whether the return means 41b transmits data that a gas meter 20 measures once by the response message or consecutively transmits them three times. Namely, a setting operation part 48 is controlled at a site in accordance with received power level from the slave machine 40 to the master machine. When received power is low, it is considered that a communication success rate is deteriorated. Thus, data are set to consecutive three times transmission when the measured value of received power, which is measured at the time of site execution, is less than a prescribed value. When received power exceeds the prescribed value, data are set so that they are transmitted only once.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless metering system suitable for metering the usage of gas, water, electric power, etc., in particular, the usage of fuel gas.

[0002]

2. Description of the Related Art Conventionally, the amount of fuel gas used, such as city gas or propane gas, has been measured by a gas meter, and meter readers have been to go around each house and check the gas meter for meter reading. However, the conventional method in which the meter reader visually checks the gas meter requires a large number of personnel, and also has a high possibility of misidentifying the usage amount.
Recently, a technology for transmitting meter reading values to a center using a public line has been proposed. Furthermore, connecting the gas meters to the public line via a wired connection is cumbersome, so the master unit is connected to the public line and a slave unit is installed in the gas meter. It has been considered to transmit and receive data wirelessly. That is, when confirming the gas usage, the center calls the slave unit wirelessly from the center through the master unit, and the slave unit wirelessly returns the measurement value of the gas meter to the master unit to notify the center of the gas usage amount. It is.

In this type of wireless meter reading system, since the slave unit is driven by a battery as well as a gas meter, the power consumption must be reduced so that the frequency of battery replacement is about once every ten years. Since the transmission frequency of the slave unit is very low, most of the power consumption in the slave unit occurs in the reception standby state. Therefore, it is considered that the power consumption of the slave unit can be reduced by intermittently performing the carrier sense in the reception standby state of the slave unit and reducing the frequency.

[0004] Based on such knowledge, a technique of setting the time interval of the carrier sense of the slave unit to about once every 20 seconds and transmitting a message longer than this time interval when calling the slave unit from the master unit has been proposed. It is considered. In other words, the slave unit performs carrier sense at least once during transmission of a message from the master unit, whereby a link can be established between the master unit and the slave unit.

[0005]

The communication success rate of the radio signal transmitted between the master unit and the slave unit depends on the reception power on the receiving side. descend. In particular, since the slave unit has to reduce power consumption, the transmission power is relatively small, and therefore, there is a problem that the communication success rate is significantly reduced depending on the positional relationship between the master unit and the slave unit and the use environment. .

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a wireless metering system capable of increasing the communication success rate even under the condition where the received power is small.

[0007]

According to a first aspect of the present invention, there is provided a master unit connected to a public line and a slave unit connected to a meter to be read. In a wireless meter reading system for transmitting and receiving data by a wireless signal and transmitting the measured value of the meter through a public line, a retransmitting means for retransmitting when data transmission from the child device to the parent device fails, a maximum number of retransmissions And a retransmission number adjusting means for adjusting the number of retransmissions is provided in the slave unit.

According to a second aspect of the present invention, in the first aspect of the present invention, there is provided a receiving strength detecting means for detecting a receiving strength of a radio signal transmitted from a slave unit, and the maximum number of retransmissions increases as the receiving strength decreases. In addition, an adjustment instructing means for instructing the retransmission number adjusting means is provided in the master unit.

According to a third aspect of the present invention, there is provided a master unit connected to a public line and a slave unit connected to a meter to be read, and data is transmitted and received between the master unit and the slave unit by a radio signal. In the wireless meter reading system for transmitting the measurement value of the meter through a public line, the slave unit intermittently detects a radio signal from the master unit at a fixed time interval during reception standby, and the time interval And a detection interval adjusting means for adjusting the distance.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the reception intensity detecting means for detecting the reception intensity of the radio signal transmitted from the slave unit, and the time interval for detecting the radio signal as the reception intensity decreases, An adjustment instruction means for instructing the detection interval adjustment means to shorten the detection interval is provided in the master unit.

According to a fifth aspect of the present invention, there is provided a master unit connected to a public line and a slave unit connected to a meter to be read, and data is transmitted and received between the master unit and the slave unit by a radio signal. In the wireless meter reading system that transmits the measurement value of the meter through a public line, the slave unit includes a return unit that returns a response to a wireless signal from the master unit to the master unit, and the master unit receives a response from the slave unit. It is provided with retry means for retransmitting the radio signal to the slave unit when confirmation is impossible, and retry number adjusting means for adjusting the maximum number of retransmissions.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, there is provided a receiving strength detecting means for detecting a receiving strength of a radio signal transmitted from a slave unit, and an upper limit value of a maximum number of retransmissions as the receiving strength is lower. An adjustment instructing unit for instructing the retry number adjusting unit to increase the number is provided in the master unit.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) In a wireless meter reading system of the present invention, as shown in FIG. 1, a center 10 for collecting meter reading data is connected to a public line 50 via a C-NCU (network controller) 51. Connected to. T-NC on the public line 50
A U (network controller) 52 is connected, and the T-NCU 52 selectively connects the telephone 53 and the base unit 30 to the public line 50. That is, the T-NCU 52 always connects the telephone 53 to the public line 50, and the master unit 30 is connected to the public line 50 as necessary.

Master device 30 has a function of transmitting and receiving a radio signal, and exchanges data with slave device 40 by radio signal. In addition, the handset 40 has a gas meter 2 as an object of meter reading.
0 is connected. The gas meter 20 is a so-called microcomputer meter, which not only measures the amount of fuel gas used, but also detects abnormalities such as earthquakes, gas leaks, and battery exhaustion, and performs processes such as plugging when abnormalities occur. Having. Since the meter reading of the fuel gas consumption is performed from the center 10 through the master unit 30 and the slave unit 40, the center 10
The T-NCU 52 is controlled by the control signal from the
0 is connected to the public line 50, but the notification accompanying the occurrence of the abnormality transmits data from the slave unit 40 to the center 10 through the master unit 30. In this case, the master unit 30 controls the T-NCU 52 to 30 is connected to the public line 50.

Although the master unit 30 and the slave unit 40 generally have a one-to-one correspondence, a one-to-many correspondence may be used. The slave unit 40 is arranged adjacent to or built into the gas meter 20, and the master unit 30 is arranged inside a house or outside in a detached house, and is arranged in an elevator or a control room in an apartment house. Further, master device 30 may be arranged on a utility pole or the like together with T-NCU 52. In this case, the telephone 53 is unnecessary.

In the following, for the sake of simplicity, the description will be made on the assumption that the master unit 30 and the slave unit 40 correspond one-to-one. Used.

As shown in FIG. 2, the master unit 30 has a microcomputer 31 as a main component, and a memory 32 used for temporary storage of data transmitted and received between the center 10 and the slave unit 40.
Is provided. The microcomputer 31 is a communication interface 33
Is connected to the T-NCU 52 via the communication interface 34 and to the wireless transmission / reception unit 35 via the communication interface 34. An antenna 36 is connected to the wireless transmitting / receiving unit 35,
Transmit and receive wireless signals between Power is supplied to master device 30 from a commercial power supply.

The slave unit 40 has substantially the same configuration as the master unit 30, and as shown in FIG. 3, is mainly configured by a microcomputer 41, and data transmitted and received between the master unit 30 and the gas meter 20. And a memory 42 used for temporary storage of data.
A wireless transmission / reception unit 44 is connected to the microcomputer 41 via a communication interface 43. An antenna 45 is connected to the wireless transmission / reception unit 44 and transmits / receives a wireless signal to / from the parent device 30. The microcomputer 41 has a communication interface 46.
The gas meter 20 is connected via the. As the power supply 47 of the slave unit 40, a battery made of a lithium battery is used.

As is clear from the above description, the center 1
Only the transmission line between the master unit 30 and the slave unit 40 is a wireless transmission line, and the other is a wired transmission line, and the gist of the present invention is a wireless transmission line. In the following, the master unit 30
The procedure of the wireless signal between the terminal and the slave 40 will be described.

The master unit 30 and the slave unit 40 always carry out carrier sense at a cycle of 18 seconds, and when transmitting information to each other, as shown in FIG.
Is sent for 20 seconds. Now, assuming that the center 10 requests the gas meter 20 to transmit the usage amount, at least one of the carrier detection means 41a provided in the slave unit 40 while the startup message STX is transmitted from the master unit 30 for 20 seconds. At this time, the activation message STX is detected. Therefore, if the ID included in the activation message STX matches the ID set in the child device 40, the child device 40 sends the response message RTX to the parent device 30 by the return means 41b. I will send it back. The return means 41b transmits the data DT such as the usage amount measured by the gas meter 20 only once or continuously three times by the response message RTX (three times continuous transmission).
It is configured to be. Whether the data DT is transmitted only once or three times in the response message RTX is set by the setting operation unit 48 provided in the slave 40. That is, the setting operation unit 48 is adjusted on site according to the received power from the slave unit 40 in the master unit 30. If the received power is small, it is considered that the communication success rate is reduced. Therefore, when the measured value of the received power measured at the time of construction at the site is equal to or less than a specified value, three consecutive transmissions are set. When the received power exceeds a prescribed value, the same data DT is transmitted only once.

Incidentally, in order to increase the communication success rate when the received power is small, a technique of transmitting the data DT a plurality of times in one response message RTX and transmitting the response message RTX a plurality of times is also employed. . That is, the master unit 30 is configured to return an acknowledgment ACK to the slave unit 40 when successfully receiving the response message RTX from the slave unit 40,
Acknowledgment ACK within a certain time after sending response message RTX
Is not returned to the child device 40, the retransmission means 41c is sent to the child device 40 so that the response message RTX is retransmitted from the child device 40.
Is provided. The maximum number of retransmissions of the response message RTX is restricted. Here, it is considered that the higher the received power at the base unit 40, the higher the communication success rate is. Therefore, when the received power is equal to or less than a predetermined value, the maximum number of retransmissions is set larger. That is,
In the same way as the number of continuous feeds, the child device 4
The maximum number of retransmissions is set to three by measuring the reception power from 0 and adjusting the setting operation unit 48 provided in the slave unit 40 when the reception power is equal to or less than the specified value. in this way,
The setting operation section 48 functions as retransmission number adjusting means. When the received power exceeds the prescribed value, retransmission is not performed, and the response message RTX is transmitted only once, thereby preventing an increase in power consumption in the slave unit 40.

In the transmission of a radio signal between the master unit 30 and the slave unit 40, a fading phenomenon is liable to occur because radio waves are reflected by an obstacle such as a building and interference or polarization disturbance occurs. When the fading phenomenon occurs, a period during which the received power is large and a period during which the received power is small occur. Therefore, it is necessary to increase the probability of transmitting a radio signal during the period when the received power is large. In particular, when the reception power is low on average, the communication success rate decreases unless a wireless signal is transmitted during the period when the reception power increases. Therefore, the time interval for retransmitting the response message RTX can be adjusted so that the time interval for retransmitting the response message RTX does not coincide with the fading cycle. The retransmission time interval may be adjusted by the setting operation unit 48 according to the reception power at the base unit 30 measured in the field. Here, the smaller the received power, the shorter the retransmission time interval is set. Note that the response message RTX has a maximum number of times set to three when retransmitting, so that the retransmission time interval can be adjusted only when retransmitting.

(Embodiment 2) In the first embodiment, the number of continuous transmissions, the number of retransmissions, and the retransmission interval are adjusted on site by the setting operation unit 48 provided in the slave unit 40. At least one element of the number of continuous transmissions, the number of retransmissions, and the retransmission interval in the child device 40 can be adjusted by the wireless signal from the terminal 30. That is, as shown in FIG.
The master unit 30 is provided with a reception intensity detection unit 37 for detecting the reception intensity of the response message RTX from the slave unit 40, and an adjustment instructing unit 38 for indicating the setting contents of the slave unit 40 based on the reception intensity. In this case, the setting operation section 48 is unnecessary in the slave 40, and the microcomputer 41 and the memory 42 of the slave 40 function similarly to the setting operation section 48 by the wireless signal from the master 30. That is, the retransmission number adjusting means is realized by the microcomputer 41 and the memory 42.

The response message R received by the base unit 30
The reception intensity of the TX is detected by the reception intensity detection means 37, and the reception intensity is compared with a specified value. If the reception intensity is smaller than the specified value, the number of continuous transmissions or the number of retransmissions is increased to a value similar to the first embodiment. By setting, the communication success rate is improved. The process of changing the number of continuous transmissions or the number of retransmissions based on the reception strength may be performed only at the time of adjustment at the site, but may be automatically performed by the base unit 30 in a timely manner. It is also possible to give an instruction to the machine 30 and perform the operation in a timely manner. Further, when retransmission is performed, an instruction may be given to the adjustment instruction means 38 so as to adjust the retransmission time interval according to the reception strength. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 3) In Embodiments 1 and 2, the master unit 3
Although the condition at the time of transmitting the response message RTX in the slave unit 40 was adjusted according to the reception power of the response message RTX at 0,
In the present embodiment, the condition at the time of reception of the slave unit 40 is adjusted. That is, as described in the first embodiment,
Slave device 40 always carries out carrier sense at intervals of 18 seconds, and base device 30 sends a 20-second activation message STX including a call code and an ID. However, in this relationship, the child device 40 receives the activation message STX from the parent device 30 at most twice during transmission of the activation message STX. In general, the higher the number of times the same information is received, the higher the communication success rate.
In order to ensure that the slave device 40 receives the message, the number of times of the carrier sense in the slave device 40 during the transmission of the activation message STX may be increased.

Therefore, in the present embodiment, the reception power when the response message RTX from the slave unit 40 is received by the master unit 30 is measured on site, and when the reception power is smaller than the specified value, the setting operation unit 48 is operated. Thus, the time interval of the carrier sense in the slave unit 40 can be shortened. Specifically, the carrier sense is normally performed at an interval of 18 seconds, but this can be changed to an interval of 6 seconds. That is, the setting operation unit 48 functions as a detection interval adjusting unit. By performing the carrier sense in the slave 40 at one-third of the regular time interval, the number of times the slave 40 can receive the start message STX during transmission of the start message STX increases to four times. The communication success rate is improved. Other configurations and operations are the same as those of the first embodiment.

Here, similarly to the second embodiment, the setting operation unit 4
Instead of providing 8, the master unit 30 may be provided with a reception intensity detecting means 37 and an adjustment instructing means 38 as shown in FIG.
That is, the reception strength detection means 37 of the base unit 30 detects the reception strength of the response message RTX from the handset 40, and when the reception strength is equal to or less than the specified value, the reception strength is specified in the handset 40 through the adjustment instruction means 38. The time interval of the carrier sense is changed to be shorter.

(Embodiment 4) This embodiment is to improve the communication success rate of the radio signal from the master unit 30 to the slave unit 40 as in the third embodiment. That is, in the above embodiment, the wireless signal is transmitted only once from the master unit 30 to the slave unit 40. However, in the present embodiment, if the communication is not successful, the master unit 30 sends the wireless signal to the slave unit 40. By transmitting the wireless signal a plurality of times, the communication success rate is increased.

As shown in FIG. 6, the microcomputer 31 of the master unit 30 is provided with retry means 41a.
Is provided with a setting operation section 39. That is, base unit 30 transmits a wireless signal (for example, start message STX) to handset 40.
Is waited for a certain period of time after transmission of the response message, and a radio signal (for example, a response message RT)
If the parent device 30 cannot receive X), the parent device 30 retransmits the same wireless signal to the child device 40 by the retry means 41a. In this way, the success of communication is
Is not confirmed, the same wireless signal is retransmitted from the master unit 30 to the slave unit 40, and the maximum number of retransmissions is adjusted by the setting operation unit 39 as a retry number adjustment unit. If the number of retransmissions from the master unit 30 to the slave unit 40 increases, the reception probability at the slave unit 40 increases. Therefore, when the reception power at the master unit 30 is equal to or less than a specified value at the site, the master unit 30 The maximum value of the number of times of transmission of the wireless signal to 40 is set to a large value.

Further, similarly to the second embodiment, in the present embodiment, the master unit 30 can also be provided with the reception intensity detecting means 37 and the adjustment instructing means 38. That is, the reception strength detection means 37 of the base unit 30 detects the reception strength of the response message RTX from the slave unit 40, and when the reception strength is equal to or less than the specified value, the adjustment instructing means 38 transmits the retransmission data specified by the retry means 31a. Change the maximum number. In this case, the setting operation section 39 is unnecessary, and the retry number adjusting means is realized by the microcomputer 31 and the memory 32. Other configurations and operations are the same as those of the first embodiment.

[0031]

According to a first aspect of the present invention, there is provided a base unit connected to a public line and a slave unit connected to a meter to be read. Retransmitting means for retransmitting when data transmission from the slave unit to the master unit fails, in a wireless meter reading system for transmitting and receiving data by a wireless signal between the transmitters and transmitting the measured value of the meter through a public line; Re-transmission number adjusting means for adjusting the maximum number of re-transmissions is provided in the slave unit. By providing the re-transmission number adjusting means in the slave unit, when the reception power at the master unit is small, the re-transmission number on the slave unit side is reduced. To increase the communication success rate, and when the received power at the master unit is large, the number of retransmissions of the slave unit can be reduced to suppress an increase in power consumption.

According to a second aspect of the present invention, in the first aspect of the present invention, there is provided a receiving strength detecting means for detecting a receiving strength of a radio signal transmitted from a slave unit, and the maximum number of retransmissions increases as the receiving strength decreases. The main unit is provided with an adjustment instruction means for instructing the retransmission number adjustment means, and the adjustment instruction means for instructing the retransmission number adjustment means provided on the slave unit is provided on the master unit, so that the number of retransmissions is reduced. The setting can be performed from the master unit, and the number of retransmissions can be automatically set together with the detection of the reception strength, and can be set through a public line.

According to a third aspect of the present invention, there is provided a master unit connected to a public line and a slave unit connected to a meter to be measured, and data is transmitted and received between the master unit and the slave unit by radio signals. In the wireless meter reading system for transmitting the measurement value of the meter through a public line, the slave unit intermittently detects a radio signal from the master unit at a fixed time interval during reception standby, and the time interval The detection interval adjusting means is provided in the slave unit, so that when the reception power at the master unit is small, the slave unit detects a carrier from the master unit. By shortening the time interval, the communication success rate can be increased, and when the reception power at the master unit is large, the time interval for detecting the carrier at the slave unit can be increased to suppress an increase in power consumption.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the reception intensity detecting means for detecting the reception intensity of the radio signal transmitted from the slave unit, and the time interval for detecting the radio signal as the reception intensity decreases, Adjustment instructing means for instructing the detection interval adjusting means to shorten the length is provided in the master unit, and by providing the master unit with adjustment instructing means for instructing the detection interval adjusting means provided in the slave unit, The carrier detection time interval can be set from the master unit, and the carrier detection time interval can be automatically set or set through a public line in addition to the reception intensity detection.

According to a fifth aspect of the present invention, there is provided a master unit connected to a public line and a slave unit connected to a meter to be read, and data is transmitted and received between the master unit and the slave unit by radio signals. In the wireless meter reading system that transmits the measurement value of the meter through a public line, the slave unit includes a return unit that returns a response to a wireless signal from the master unit to the master unit, and the master unit receives a response from the slave unit. It has retry means for retransmitting the wireless signal to the slave unit when it cannot be confirmed, and retry number adjustment means for adjusting the maximum number of retransmissions, and sets the upper limit of the number of retransmissions of the wireless signal from the master unit to the slave unit. By providing the retry frequency adjusting means in the master unit, when the reception power at the master unit is small, the number of retransmissions of the radio signal from the master unit to the slave unit can be increased to increase the communication success rate.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, there is provided a receiving strength detecting means for detecting a receiving strength of a radio signal transmitted from a slave unit, and an upper limit value of a maximum number of retransmissions as the receiving strength is lower. Adjustment instruction means for instructing the retry number adjustment means to increase the size is provided in the parent machine,
By providing an adjustment instructing means for instructing the retry number adjusting means provided in the master unit to the master unit, the number of retransmissions of the radio signal from the master unit to the slave unit can be set by the master unit. , The number of retransmissions of the wireless signal from the master unit to the slave unit can be automatically set or set via a public line.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration of a first embodiment of the present invention.

FIG. 2 is a block diagram showing a parent device used in the embodiment.

FIG. 3 is a block diagram showing a slave unit used in the embodiment.

FIG. 4 is an operation explanatory view of the above.

FIG. 5 is a block diagram showing a master unit used in Embodiment 2 of the present invention.

FIG. 6 is a block diagram showing a master unit used in Embodiment 4 of the present invention.

[Explanation of symbols]

 Reference Signs List 10 center 20 gas meter 30 master unit 31a retry means 37 reception intensity detection means 38 adjustment instruction means 39 setting operation unit 40 slave unit 41a carrier detection means 41b return means 41c retransmission means 48 setting operation unit 50 public line

 ──────────────────────────────────────────────────の Continued on the front page (71) Applicant 000005821 Matsushita Electric Industrial Co., Ltd. 000005234 Fuji Electric Co., Ltd. 1-1-1, Tanabe-Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa (72) Inventor Masahiro Yasui 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi Inside Osaka Gas Co., Ltd. (72) Inventor Shoji Yamaguchi Inside Osaka Gas Co., Ltd. 4-1-2 Hirano-cho, Chuo-ku, Osaka-shi (72) Inventor Noriaki Iwamoto Inside Osaka Gas Co., Ltd. 4-1-2 Hirano-cho, Chuo-ku, Osaka-shi (72) Inventor Akira Higashino Osaka 4-1-2, Hirano-cho, Chuo-ku, Osaka City Osaka Gas Co., Ltd. (72) Inventor Mamoru Suzuki Minamikashiwa Park 103, 1-4-5 Toyosumi, Kashiwa-shi, Chiba 103 (72) Akiya Kiyohisa Ishikawa 2-7-9 Innai, Funaibashi-shi, Chiba 401 (72) Inventor Jun Fujiwara 1-6-14-901, Morishita, Koto-ku, Tokyo (72) Inventor Takahiro Yuzawa 1 Keishima, Sumida-ku, Tokyo −47−10−604 (72) Inventor Tatsuya Ichihashi 19-18 Sakuradacho, Atsuta-ku, Nagoya-shi, Aichi Prefecture Inside Higashi-Hongas Co., Ltd. In-company (72) Inventor Katsunori Tanie 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Masahiro Yamamoto 1006 Okadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Kawai Toshihiko 70, Yanagicho, Kochi-ku, Kawasaki-shi, Kanagawa Prefecture Inside the Toshiba Yanagicho Plant (72) Inventor Masaharu Takeda 70, Yanagicho, Kochi-ku, Kawasaki-shi, Kanagawa Prefecture Inside the Toshiba Yanagicho Plant (72) Inventor Eiji Matsumoto Kawasaki, Kawasaki-shi, Kanagawa Prefecture 1-1, Tanabe-Shinden-ku, Fuji Electric Co., Ltd. (72) Inventor Shiro Kondo Kana Fuji Electric Co., Ltd. (1-1) Tanabe Nitta, Kawasaki-ku, Kawasaki-ku, Japan (72) Inventor Takeshi Takeshi Nanagami 1-1, Tanabe-Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa F-term in Fuji Electric Co., Ltd. 5K067 AA25 BB27 CC21 DD24 DD51 EE02 EE10 GG07 HH28 5K101 KK12 LL11 RR13 RR14

Claims (6)

[Claims] A master unit connected to a public line and a slave unit connected to a meter to be read are provided, and data is transmitted and received by a wireless signal between the master unit and the slave unit. In a wireless meter reading system that transmits the measured value of the slave unit through a public line, the slave unit includes a resending unit that resends when data transmission from the slave unit to the master unit fails and a resending number adjusting unit that adjusts a maximum number of resendings. A wireless meter reading system, which is provided in the system. 2. A reception strength detection means for detecting a reception strength of a radio signal transmitted from a slave unit, and an adjustment instruction means for instructing a retransmission number adjustment means to increase the maximum number of retransmissions as the reception strength decreases. 2. The wireless meter reading system according to claim 1, wherein the base unit is provided. 3. A master unit connected to a public line and a slave unit connected to a meter to be read, and data is transmitted and received by a wireless signal between the master unit and the slave unit, and the meter uses the meter. In the wireless meter reading system for transmitting the measured value of the master unit through a public line, the slave unit intermittently detects a radio signal from the master unit at a predetermined time interval during reception standby, and a detection interval for adjusting the time interval. A wireless meter reading system provided with adjusting means. 4. A receiving strength detecting means for detecting the receiving strength of the radio signal transmitted from the slave unit, and an adjustment for instructing the detecting interval adjusting means to shorten a time interval for detecting the radio signal as the receiving strength decreases. 4. The wireless meter reading system according to claim 3, wherein the pointing device is provided in the parent device. 5. A master unit connected to a public line, and a slave unit connected to a meter to be read, wherein data is transmitted and received by radio signals between the master unit and the slave unit, and the meter transmits and receives the data. In a wireless meter reading system that transmits the measured value of the slave unit through a public line, the slave unit includes a return unit that returns a response to the wireless signal from the master unit to the master unit. A wireless metering system, comprising: retry means for retransmitting a wireless signal to a device; and retry number adjusting means for adjusting the maximum number of retransmissions. 6. A receiving strength detecting means for detecting a receiving strength of a radio signal transmitted from a slave unit, and an adjusting means for instructing a retry number adjusting means to increase an upper limit value of a maximum number of retransmissions as the receiving strength decreases. 6. The wireless meter reading system according to claim 5, wherein the pointing device is provided in the parent device.