JPH09224291A - Signal transmission system and metering system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need for revision of the entire system timing even when a radio channel receives a high speed conversion by adopting a radio channel on the way of wired data transmission lines so as to reduce the wiring work cost for wired transmission lines, adopting a high transmission speed for the radio channel so as to be immune to noise. SOLUTION: Data are sent from a device 9 at a transmission seed of 300bps via a wired transmission line 11. A 1st speed converter 13 receives the data and receives one character, e.g. D1 and stores it into a memory. After the reception of the character D1 , the character D1 is continuously sent to a radio transmission line 15 for 32 times at a high speed of 9600pbs. Upon the receipt of 32 characters D1 at a high speed by a 2nd speed converter 14, the converter converts the character into a low speed of 300bps and the converted character is sent to a device 10 via the wired transmission line 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital electric signal transmission system and a meter reading system using this transmission system.

[0002]

2. Description of the Related Art In an automatic meter reading system for automatically metering a water meter, a gas meter or the like using a telephone line, a terminal transmitter such as a T-NCU is provided between a meter (hereinafter also referred to as a terminal) and a telephone line. Therefore, data transmission is performed by wire communication between the meter and the meter-reading center.

The transmission rate is usually 300 bits / second (hereinafter referred to as b
(abbreviated as ps) is used. An automatic meter reading system of this type is shown in FIG. 1 is a center device for automatic meter reading,
2 is a telephone line, 3 is a terminal transmitter such as T-NCU or U-NCU, 4 is a wired transmission line made of a cable, 5 is water
It is a meter for gas, etc.

Data is transmitted at a transmission rate of 300 bps through the telephone line 2 and the wired transmission line 4. Therefore, if the transmission data is n bits and the transmission speed is generally B ₀ (bps), the communication time takes n / B ₀ seconds, and this time is proportional to the data length.

[0005]

In the above prior art,
There is a drawback that the wiring work cost of the wire transmission line 4 between the terminal transmitter 3 and the meter 5 is high.

Therefore, as shown in FIG. 7, the wired transmission line 4
The first wireless unit 6 and the second wireless unit 7
It is conceivable that the two wireless units 6 and 7 are connected by the wireless transmission line 8.

Since wireless communication is more susceptible to disturbances such as noise than wired communication, the wireless transmission path 8 is set to a high transmission speed to transmit data in a short time and reduce the error occurrence rate. For example, 9600bp of 1200bps or more
It is conceivable to wirelessly communicate with s.

Generally, the transmission speed of the wire transmission line 4 and the telephone line 2 is B ₀ (bps), and the transmission speed of the wireless transmission line 8 is B
_{If 1} (bps) is set, the communication time required to transmit n-bit data requires extra time for speed conversion between the first and second wireless units. This extra time becomes [(1 / B ₀ ) + (1 / B ₁ )] n seconds, and this time becomes longer in proportion to the data length.

Therefore, when trying to transmit a large amount of data, there is a problem that extra time for speed conversion is increased and the timeout time of the transmission system is caught and communication may not be established.

In the first and second wireless units, n
After the reception of all bit data, the speed is converted,
There is a problem that a memory for temporarily storing data is required, and its capacity requires a large capacity corresponding to the maximum amount of data.

Such a problem occurs not only in the automatic meter reading system, but also in a transmission system in which a wired transmission line having a low transmission speed and a wireless transmission line having a high transmission speed are generally connected.
Therefore, an object of the present invention is to provide a signal transmission system and a meter reading system that can solve such problems.

[0012]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
The present invention relates to a wired data transmission system,
Make a part of the transmission line wireless and change the transmission speed of this wireless section.
Even if it is faster than the transmission speed of the wired section,
So that the transmission speed seems to be the same as the wired one.
And use it without changing the existing system
The first aspect of the invention is a communication system that can be used.
Between the container (9) and the second device (10), one end is the first
A first wired transmission line (11) connected to the device (9),
Second wired transmission with one end connected to the second device (10)
Line (12), first wired transmission line (11) and second wired
A first speed converter (1) is provided between the other ends of the transmission path (12).
3) and the second speed converter (14) through the wireless transmission line
Connected at (15) and connected continuously between both devices (9) and (10)
Multiple characters (..., D_n-1, D_n, D_{n + 1},…)
A system for transmitting data consisting of one speed
The converter (13 or 14) is one wired transmission line (11 or 14).
Data from one device (9 or 10) via 12)
When receiving and transmitting to the wireless transmission line (15)
One of the tractors (D_n) Each time a wired transmission line (1
1, 12) higher than the transmission speed Bo (bps)
Degree B₁B in (bps)₁/ B ₀Only one time in a row
Character (D_n), And the other speed converter (14
Or 13) is the one speed converter (13 or 14)
The other data is received via the wireless transmission line (15)
When transmitting to the wired transmission line (12 or 11) of
One character (D_n) To B₁/ B₀Receiving only once
If you agree, slow transmission speed B₀Send once at (bps)
This is a signal transmission method characterized in that

A second aspect of the present invention is a meter reading system for automatically metering a meter (5) by a center device (1), wherein the center device (1) and the terminal transmitter (3) are connected by a telephone line (2). In addition, between the terminal transmitter (3) and the meter (5), a first wired transmission line (4A) having one end connected to the terminal transmitter (3) and one end connected to the meter (5). Second wired transmission path (4B) and first wired transmission path (4A)
And a first wireless unit (6A) and a second wireless unit (7A) provided at the other ends of the second wired transmission path (4B) are connected by a wireless transmission path (8A), and a center device ( In the automatic meter reading system that transmits a telegram consisting of a plurality of consecutive characters between 1) and the meter (5), one wireless unit (6A or 7A) is connected via one wired transmission path (4A or 4B). When receiving data from the terminal transmitter (3) or meter (5) and transmitting it to the wireless transmission path (8A), each time one of the characters (D ₁ ) is received,
The one character (D ₁ ) is continuously transmitted B ₁ / B ₀ times at a transmission speed B ₁ (bps) higher than the transmission speed B ₀ (bps) of the wired transmission path (4A, 4B), and the other character is transmitted. The wireless unit (7A or 4A) receives data from the one wireless unit (4A or 7A) via the wireless transmission line (8A) and transmits the data to the other wired transmission line (4B or 4A). The one character (D ₁ ) is B ₁ /
If B ₀ times are continuously received, the slow transmission rate B ₀ (bp
The meter reading system is characterized by transmitting once in s).

According to a third aspect of the present invention, in the meter reading system according to the second aspect, one character (D ₁ ) is B ₁ / B ₀ times due to a communication error in the wireless unit (6A or 7A) receiving the wireless signal. Even if all data cannot be received normally, if the data can be received normally for a certain number of times or more, it is assumed that the received data is correct and transmission is started to the wired transmission path (4A or 4B) at the timing of the reception end of B ₁ / B ₀ times. It is characterized by.

According to a fourth aspect of the present invention, in the signal transmission system according to the first aspect, the transmission rate B ₁ (bp) of the wireless transmission line (8A).
s) is the transmission speed B ₀ (b of the wired transmission path (4A or 4B)
ps) is an integral multiple.

According to a fifth aspect of the present invention, in the meter reading system according to the second or third aspect, the transmission speed B ₁ (bps) of the wireless transmission line (8A) is the wired transmission line (4A or 4B).
It is characterized in that it is an integral multiple of the transmission rate B ₀ (bps).

[0017]

1 (a), 1 (b) and 1 (c) are preferred embodiments of the signal transmission system of the present invention, in which 9 is a first device, 10 is a second device, and 11 is one end. Is a first wired transmission line connected to the first device 9, 12 is a second wired transmission line having one end connected to the second device 10, and 13 is another end of the first wired transmission line 11. First speed converter connected, 14
Is a second speed converter connected to the other end of the second wired transmission path 12, and a wireless transmission path 15 is provided between both speed converters 13 and 14.
Connected by

In the first and second wired transmission lines 11 and 12,
Data transmission speed is B₀(Bps) on the wireless transmission line 15
Is the data transmission speed B₀Many times faster than (bps)
Of B ₁(Bps). B₁Is B₀An integer multiple of
is there.

Now, one device, for example, the first device 9 has data consisting of a plurality of consecutive characters ..., D _n-1 , D.
Speed converters 13 and 14 for transmitting _n , D _{n + 1} , ...
The speed conversion at will be described.

The data received by the first speed converter 13 from the first device 9 via the wire transmission path 11 are characters D _n-1 , D _n , D _{n + 1,} etc. as shown in FIG. 1 (b). Are consecutive in sequence, and the transmission rate is B ₀ (bps).

The first speed converter 13 receives the signal from the first device 9 and stores it in the memory, while at the same time transmitting the previously stored character to the wireless transmission line 15 at high speed. For example, when the character D _n-1 from the first device 9 is received and accumulated, this character D _n-1 is continuously transmitted at the transmission rate B ₁ (bps) B ₁ / B ₀ times by the wireless transmission line 15.
Send to Then, this character D _n-1 is B ₁ / B
_While transmitting ₀ times, the next character D _n from the first device 9 is received and stored in the memory. In this way, the characters D _n-1 , D _n , D _{n + 1} , ...
_It is converted to ₁ (bps) and wirelessly transmitted (FIG. 1 (b)).

The second speed converter receiving this radio signal transmits this character every B ₁ / B ₀ identical characters sent at a high transmission speed.
Transmission is performed once at a slow rate of ₀ (bps) (see FIG. 1).
(C)).

As described above, when the first speed converter 13 transmits at a high transmission speed, the data is always delayed by one character. This delay is (1 / B ₀ ) × (number of bits of one character).

When the second speed converter 14 transmits at a slower transmission speed, the delay becomes (1 / B ₀ ) × (the number of bits of one character).

Therefore, the bit number of one character is 10,
When the transmission rate B _{0 is set} to 300 bps and B _{1 is set} to 9600 bps, a delay of 1/300 = 33.3 ms occurs every time the transmission rate is converted, but the number of bits per character is rather independent of the length of the transmission data. It will be a fixed time determined by the transmission rate.

Since this delay time is a time that can be neglected from the viewpoint of the time-out time of the entire signal transmission system, for example, even if the transmission rate is converted in the middle, it is not possible to operate the system. The timing may be the same as when communicating at the same speed.

In the above description, the data transmission from the first device 9 to the second device 10 has been described, but the reverse transmission in which the data transmission is performed from the second device 10 to the first device 9 is also performed. Communication is possible with the same operation.

[0028]

2 to 5 are embodiments of a meter reading system of the present invention, 1 is a center device for automatic meter reading, 2 is a telephone line, 3 is a terminal transmitter such as T-NCU or U-NCU, and the center device In the telephone line 2 between the terminal 1 and the terminal transmitter 3, the transmission speed B ₀ is set to 300 bps.

Reference numeral 5 is a meter such as a water or gas meter, 4A is a first wired transmission line having one end connected to the terminal transmitter 3 and the other end connected to the first wireless unit 6A, and 4B has one end connected to the meter 5. A second wired transmission line whose other end is connected to the second wireless unit 7A, and 8A is a wireless transmission line which connects between the first wireless unit 6A and the second wireless unit 7A.

The data transmission rate on the second wired transmission line 4B is set to 300 bps, which is the same as the data transmission rate B _{0 on} the first wired transmission line 4A. The data transmission rate B _{1 on} the wireless transmission line 8A is set to 9600 bps, which is 32 times the data transmission rate B _{0 on} the two wired transmission lines 4A and 4B.

FIG. 3 (a) shows a 300 bps telegram structure on the wired transmission path, and FIG. 3 (b) shows a character structure.
In the first wireless unit 6A or the second wireless unit 7A, the procedure for converting from a slow transmission rate of 300 bps to a high transmission rate of 9600 bps is as follows. (1). When the mark is detected at 300 bps, 9600
The mark is transmitted even at bps and the STX is waited for at 300 bps. (2). 9600 when STX is received at 300 bps
32 STXs are continuously transmitted at bps. (3). While sending STX at 9600 bps,
Since the next character D ₁ is received at 300 bps,
Once the STX 32 or send followed by D ₁ and to 32 transmission. (4). Below, at 300 bps, D ₂ , D ₃ , ..., D _n , E
D ₂ at 9600 bps each time TX and BCC are received,
.., D _n , ETX, and BCC, each 32 in succession.

This conversion procedure is shown in FIG. When speed conversion is performed at the timing shown in FIG. 4, the delay time caused by conversion is only (1/300) × 10 = 33.3 ms for one character (10 bits), and this value does not depend on the data length. It is constant.

Since the time-out time of the meter reading system (communication system) using the transmission rate of 300 bps is usually about 10 seconds, the delay of 33.3 ms can be ignored and does not adversely affect the operation of the system.

Next, in the second wireless unit 7A or the first wireless unit 6A, a high transmission speed of 960
The procedure for converting from 0 bps to the slower transmission rate of 300 bps is as follows. (1). 30 when the mark signal is received at 9600 bps
Send the mark at 0 bps. (2). 3 when receiving 32 STX at 9600 bps
STX is sent at 00 bps.

Even if all 32 data cannot be received normally even if an error occurs, if the data can be received normally for a certain number of times, for example, 3 times or more, this data is regarded as correct and transmission at 300 bps is performed at the timing of receiving 32 data. Start. (3). Continuing, at 1,600 bps, D ₁ , D ₂ , ..., D
_When 32 _n , ETX, and BCC are received, each is transmitted once at 300 bps.

The processing when an error occurs is the same as the above STX.
In the same manner as in the above case, if it can be normally received a certain number of times or more, it is judged as correct and processed. This conversion procedure is shown in FIG. At the timing of FIG. 5, the delay time due to speed conversion becomes 33.3 ms as in the case of FIG. 4, so there is no adverse effect on the system.

Therefore, when this speed conversion method is used, the same timing as when communicating at 300 bps is apparently obtained even if a part of the transmission line is operated at high speed. The unit can be made wireless and can be speeded up.

In the above signal transmission system and meter reading system, when B ₁ / B ₀ is an integer, it is convenient because the timing can be easily adjusted.

[0039]

Since the signal transmission system and the meter reading system of the present invention are configured as described above, the communication timing delay due to the speed conversion is always constant regardless of the data length, and the system time-out time. From the viewpoint, it is so short that there is no problem. Therefore, even if the communication timing between the first and second devices or between the center device and the meter is set to a high transmission speed in the wireless transmission path section on the way, the existing system can be used. Can be used without modification.

The memory for storing data at the time of speed conversion may have a small capacity for one character. Furthermore, in the wireless transmission path, the same data (character) is continuously sent at a high speed by the ratio of the transmission rates (for example, 32 in the above embodiment), so that the influence of disturbance can be reduced and the reliability of the wireless communication is improved. To do.

Furthermore, the cost of wiring work between the meter and the terminal transmitter, which is the purpose of the present invention, can be reduced.

[Brief description of drawings]

FIG. 1 is a preferred embodiment of the signal transmission device of the present invention,
(A) is a block diagram, (b) is a timing diagram when converting a transmission rate to high speed, and (c) is a timing diagram when reducing a transmission rate.

FIG. 2 is a block diagram of an embodiment of the meter reading system of the present invention.

FIG. 3A is a diagram of a data structure of the embodiment of FIG.
(B) is a figure of the same character structure.

FIG. 4 is a timing diagram when converting the transmission speed of the embodiment of FIG. 2 to high speed.

5 is a timing chart when the transmission speed of the embodiment of FIG. 2 is reduced.

FIG. 6 is a block diagram of a conventional technique.

FIG. 7 is a block diagram of another prior art.

[Explanation of symbols]

1 Center Device 2 Telephone Line 3 Terminal Transmitter 4A First Wired Transmission Line 4B Second Wired Transmission Line 6A First Wireless Unit 7A Second Wireless Unit 8A Wireless Transmission Line 9 First Equipment 10 Second Equipment 11 First Wired Transmission Line 12 Second Wired Transmission Line 13 First Speed Converter 14 Second Speed Converter 15 Wireless Transmission Line B ₀ , B ₁ Transmission Speed D ₁ , D _n-1 , D _n , D _{n + 1} character

Claims (5)

[Claims] 1. A first device (9) and a second device (10)
Between the first end and the first end connected to the first device (9).
Connect the cable transmission line (11) and one end to the second device (10).
A second wired transmission line (12) connected to the first wired transmission
Between the other end of the line (11) and the second wire transmission line (12)
First speed converter (13) and second speed converter (14)
Connected via a wireless transmission line (15) via
A plurality of consecutive characters (..., D) between (10)_n-1,
D_n, D_{n + 1}, ...) for transmitting data consisting of
And one speed converter (13 or 14) is one wired transmission line
One device (9 or 10) via (11 or 12)
To receive these data and send them to the wireless transmission line (15)
One of the characters (D_n) Every time you receive
Higher than the transmission rate Bo (bps) of the transmission line (11, 12)
High transmission speed B₁B in (bps)₁/ B ₀Only once in a row
The one character (D_n) Is transmitted, and the other speed converter (14 or 13)
The data from the converter (13 or 14) is transferred to the wireless transmission line (1
5) via the other wired transmission line (12 or 1)
1) When sending to the one character (D_n)
To B₁/ B₀Slow transmission speed B if received only once
₀Signal transmission characterized by transmitting once at (bps)
method. 2. A meter reading system for automatically metering a meter (5) by a center device (1), the center device (1) and a terminal transmitter (3) being a telephone line (2).
Connected with the terminal transmitter (3) and meter (5)
Between the first wire transmission line (4A) having one end connected to the terminal transmitter (3), the second wire transmission line (4B) having one end connected to the meter (5), 1 wired transmission line (4
A) and the first wire provided at the other end of each of the second wire transmission path (4B)
Wireless unit (6A) and second wireless unit (7A)
Between the center device (1) and the meter (5) by transmitting a telegram consisting of a plurality of continuous characters, in which the wireless unit (6A or 7A) receives the data from the terminal transmitter (3) or the meter (5) via one wired transmission path (4A or 4B) and transmits the data to the wireless transmission path (8A). Transmission rate B of the wired transmission path (4A, 4B) each time one (D ₁ ) is received.
₀ B ₁ with (bps) from transmission speed B ₁ (bps)
/ B ₀ times, the one character (D ₁ ) is continuously transmitted, and the other wireless unit (7A or 4A) transmits the data from the one wireless unit (4A or 7A) to the wireless transmission path (8A). When receiving the one character (D ₁ ) B ₁ / B ₀ times consecutively when receiving it via the other wired transmission path (4B or 4A), the slow transmission speed B ₀ (bps) The meter reading system is characterized by transmitting once. 3. A wireless unit (6A) for receiving a wireless signal.
Or 7A) is a character (D) due to a communication error.
₁₎ even if not receive B ₁ / B ₀ times all successfully, if successfully received over a certain plurality of times, and the received data is correct, the wired transmission path at a timing of B ₁ / B ₀ times reception end (4A Alternatively, the meter reading system according to claim 2, wherein the transmission is started to 4B). 4. The transmission rate B ₁ (b) of the wireless transmission line (8A)
ps) is the transmission speed B of the wired transmission path (4A or 4B)
It is an integral multiple of ₀ (bps).
Described signal transmission method. 5. The transmission rate B ₁ (b) of the wireless transmission line (8A)
ps) is the transmission speed B of the wired transmission path (4A or 4B)
3. An integer multiple of ₀ (bps).
Or the meter reading system described in 3.