JP3430589B2 - Communication method and communication device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication method and a communication device, and in particular, one master station and a plurality of slave stations are connected in a ring shape, and communication is performed between the master station and the slave stations by an asynchronous method. The present invention relates to a communication method and a communication device.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
In a communication system in which one and a plurality of slave stations 72 are connected in a ring shape and communication is performed by the start-stop synchronization method, one frame which is a unit of communication from the master station 71 to the slave station 72 identifies synchronization information and slave stations. It consists of address information and data.

Therefore, when the number of slave stations 72 increases,
Since the address information is transmitted to each slave station 72,
There is a drawback that the transmission efficiency is reduced.

Therefore, as disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 2-309730, after the synchronization signal, data for each slave station is made continuous to form a collective frame, and address information of each slave station is formed. There is known a communication system in which is eliminated to improve transmission efficiency.

[0005]

By the way, in the above-mentioned communication system, since the communication is performed by the start-stop synchronization method, the transmission signal is transmitted every time one slave station 72 is passed due to the error of the clock included in the slave station 72. If the number of slave stations increases due to a change in the timing of No. 1, there is a problem that the synchronization signal provided at the beginning of the live frame cannot synchronize in the latter half of the live frame.

The present invention has been made in view of the above problems, and can improve the transmission efficiency.
Another object of the present invention is to provide a communication method and a communication device that can reliably achieve synchronization even if the number of slave stations increases.

[0007]

In order to solve the above problems, a communication method according to the present invention is a communication method in which one master station and a plurality of slave stations are connected to a ring-shaped transmission line for communication. In the above, one frame of communication data transmitted from one master station to each slave station is composed of synchronization information and data, and a frame consisting of all slave stations is collected and a series of frames is added with header information at the beginning. The master station configures data, and the master station transmits the communication data to the plurality of slave stations via the transmission path. Each slave station receives the communication data, detects the synchronization information of a series of frames, counts the synchronization information, and receives the communication data from the master station corresponding to the own frame. And the slave station that received the communication data from the master station,
The own station frame is replaced with a frame addressed to the master station, and communication data is sequentially transmitted to the transmission path.

Further, the communication device according to the present invention is a communication device for communicating by connecting one master station and a plurality of slave stations to a ring-shaped transmission path, and transmitting from one master station to each slave station. Each frame of communication data is composed of synchronization information and data, and frames for all slave stations are collected to form communication data consisting of a series of frames with header information added to the head, and communication data is transmitted through a transmission line. And transmitting communication data to a plurality of slave stations, receiving communication data, detecting synchronization information of a series of frames, counting synchronization information and receiving communication data from the parent station corresponding to the own frame The slave station receiving unit that receives the data from the master station, and the slave station transmitting unit that sequentially transmits the communication data to the transmission line by replacing the own station frame with the frame addressed to the master station with respect to the master station. Obtain.

[0009]

[0010]

[0011]

In the present invention, one frame of communication data transmitted from one master station to each slave station is composed of synchronization information and data, and a frame for all slave stations is collected and header information is added at the beginning. Composing communication data composed of frames, and the master station transmits the communication data to a plurality of slave stations via the transmission path. Each slave station receives the communication data, detects the synchronization information of a series of frames, counts the synchronization information, and receives the communication data from the master station corresponding to the own frame. Then, the slave station, which has received the communication data from the master station, replaces its own frame with a frame addressed to the master station, and sequentially transmits the communication data to the transmission path.

[0012]

[0013]

[0014]

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a communication method and a communication device according to the present invention will be described below in detail with reference to the drawings. In this embodiment, the present invention is applied to a communication system in which one master station and a plurality of slave stations are connected in a ring shape for communication, and FIG. 1 is a block diagram showing the configuration of the master station. 2 is a block diagram showing the configuration of the slave station, and FIG. 3 is a block diagram showing the configuration of this communication system.

First, the communication system will be described. For example, as shown in FIG. 3, this communication system includes one master station 10 and n slave stations 30 _i (i = 1 to n), and the master station 10 and n slave stations 30 _i are It is connected in a ring. The start-stop synchronization method is used as a communication method between these stations.

Next, the configurations of the master station 10 and the slave stations 30 _i will be described. As shown in FIG. 1, for example, the master station 10 reads a transmission data storage unit 11 that stores data to be transmitted to each slave station 30 _i and data stored in the transmission data storage unit 11, by adding a start bit, respectively as well as a frame to be transmitted to each slave station 30 _i to constitute a series of frames to collect frames for all slave station 30 _i, a header indicating the head to the top of the series of frames A parallel / serial conversion unit 12 that adds information to form a transmission signal, a transmitter 13 that outputs the transmission signal from the parallel / serial conversion unit 12 to a transmission path, and a transmission signal from the slave station 30 _n Receiver 14, a basic clock generator 15 for generating a basic clock, and the receiver 14 using the basic clock from the basic clock generator 15. A start bit detector 16 for detecting a start bit of the received transmission signal, and a receiver for generating a reception clock based on the start bit detected by the start bit detector 16 and the basic clock from the basic clock generator 15. With the clock generation unit 17, the waveform shaping unit 18 that shapes the waveform of the transmission signal received by the receiver 14 by the reception clock from the reception clock generation unit 17, and the reception clock from the reception clock generation unit 17, A serial / parallel conversion unit 19 for extracting data of each slave station 30 _i from the transmission signal waveform-shaped by the waveform shaping unit 18 and data of each slave station 30 _i from the serial / parallel conversion unit 19 are stored. The reception data storage unit 20 is provided.

On the other hand, the slave station 30 _i , for example, as shown in FIG. 2, has a receiver 31 for receiving a transmission signal, a basic clock generating section 32 for generating a basic clock, and a basic clock from the basic clock generating section 32. With this, the start bit detection unit 33 that detects the start bit of the transmission signal received by the receiver 31 and the number of start bits from the start bit detection unit 33 are counted to indicate that the data is for the own station. A start bit counter 34 that outputs a select signal, a transmission clock generator 35 that generates a transmission clock based on the start bit from the start bit detector 33 and the basic clock from the basic clock generator 32, and the transmission clock. Transmission transmitted by the receiver 31 according to the transmission clock from the generation unit 35 Waveform shaping unit 36 for shaping the waveform
And a serial / parallel conversion unit 37 for extracting data from the transmission signal from the waveform shaping unit 36 by the transmission clock from the transmission clock generation unit 35, and a serial / parallel conversion unit by a select signal from the start bit counter 34. A selector 38 for selecting the data for its own station from the data from the parallel converter 37, and the selector 3
Received data storage unit 39 for storing data of its own station from 8
And a transmission data storage unit 40 for storing data to be transmitted to the master station 10 and a transmission clock from the transmission clock generation unit 35 to read the data stored in the transmission data storage unit 40, Based on a select signal from the parallel / serial converter 41 that adds a start bit to form a frame, and the start bit counter 34, the frame from the parallel / serial converter 41 and the waveform from the waveform shaper 36 are automatically generated. A selector 42 for switching and selecting frames for stations to form a transmission signal and a transmitter 43 for transmitting the transmission signal from the selector 42 are provided.

Here, regarding the format of the transmission signal
explain. One frame of the transmission signal (hereinafter referred to as frame 52
_i Is a single slave station, for example, as shown in FIG. 4A.
Thirty_i Start bit for 50_i And data 51_i When
Composed of. Also, all child stations 30_i Against the frame
52_i Are assembled into a series of frames 54.
At the beginning of the continuous frame 54, a header 53 indicating the beginning is
Has been added. That is, following the header 53, each slave station
Thirty_i Frame 52 _i Is a format that continues
It As the header 53, for example, a low level
A break signal in which the signal continues for two or more frames is used.

Next, the operations of the master station 10 and the slave stations 30 _i will be described. The parallel / serial conversion unit 12 of the master station 10 reads the data for each slave station 30 _i stored in the transmission data storage unit 11 as a parallel signal,
A start bit is added to each of these data to form a frame, frames for all slave stations 30 _i are collected to form a series of frames, and a break signal is added as a header to the beginning of the series of frames, Form communication data. Then, the parallel / serial conversion unit 12
Supplies the formed communication data to the transmitter 13 as a serial signal (transmission signal), and the transmitter 13
Transmits this transmission signal to the slave station 30 _i via the transmission path.

The receiver 31 of the slave station 30 _i receives the transmission signal via the transmission path and supplies the received transmission signal to the start bit detecting section 33 and the waveform shaping section 36. The start bit detection unit 33 detects the start bit of the transmission signal supplied from the receiver 31 by the basic clock from the basic clock generation unit 32, and outputs the detected start bit to the start bit counter 34 and the transmission clock generation unit 35. Supply.

The start bit counter 34 starts
The number of start bits supplied from the bit detector 33
Count, and this count value is the preset value of your station
The select signal to the selectors 38 and 42 when
Supply. The start bit counter 34 is
Is reset by the break signal (header 53)
It That is, the start bit counter 34 is
Start bit 5 from break signal 53 shown in FIG. 4A
0_i Of the frame 52 _i Received
When the signal is received, the select signal is supplied to the selectors 38 and 42.
To pay.

The transmission clock generator 35 is based on the start bit detected by the start bit detector 33 and the basic clock supplied from the basic clock generator 32.
For example, a transmission clock having a cycle corresponding to 1 bit of the transmission signal is generated, and this transmission clock is supplied to the waveform shaping unit 36, the serial / parallel conversion unit 37, and the parallel / serial conversion unit 41.

The waveform shaping section 36 shapes the waveform of the transmission signal supplied from the receiver 31 based on the transmission clock from the transmission clock generation section 35 and supplies it to the serial / parallel conversion section 37 and the selector 42.

The serial / parallel converter 37 synchronizes with the transmission clock from the transmission clock generator 35, extracts data from the transmission signal waveform-shaped by the waveform shaping unit 36, and supplies it to the selector 38.

The selector 38 selects the data of its own station from the data supplied from the serial / parallel conversion section 37 in response to the select signal supplied from the start bit counter 34, and receives the data of this station from the received data storage section 39.
Supply to. As a result, the data 51 _{i of the} own station is stored in the received data storage unit 39.

On the other hand, the parallel / serial converter 41
The data stored in the transmission data storage unit 40 is read, a start bit is added to this data to form a frame, and this frame is supplied to the selector 42.

The selector 42, based on the select signal supplied from the start bit counter 34, receives the frame from the parallel / serial converter 41 and the waveform shaping unit 3.
The transmission signal is formed by switching and selecting the frame for the own station, which is supplied from 6, and the transmission signal is supplied to the transmitter 43. Then, the transmitter 43 transmits the transmission signal from the parallel / serial conversion unit 41 to the slave station 30 _{i + 1} which is the slave station at the next stage via the transmission path.

[0029] As a result, for example, the slave station 30 _i to 1 stage Menoko station 30 _1, the slave station 30 _1, for example as shown in FIG. 4B, the master station frame 52 ₁ of the own station as necessary The transmission signal is replaced with the addressed frame 52 ₁ and the transmission signal delayed by 1 bit from the transmission signal from the master station 10 is transmitted to the slave station 30 ₂ .

Similarly, the slave station 30 ₂ replaces the frame 52 _i addressed to itself with the frame 52 _i addressed to the master station as required, that is, as shown in FIG.
0 ₂ replaces frame 52 ₂ destined to the frame 52 _{and second} main station, and transmits a transmission signal obtained by 1-bit delayed with respect to the transmission signal from the slave station 30 ₁ to the remote station 30 _3. In addition, child station 3
The above operation is similarly repeated at 0 ₃ to 30 _n ,
Slave station 30 _n, for example, as shown in FIG. 4D, each slave station 30
The frame 52 _i addressed to _i is replaced with a frame 52 _n addressed to the master station from the slave station 30 _{n as} necessary, and a transmission signal delayed by n bits from the transmission signal from the master station 10 is transmitted to the master station 10. .

Then, the receiver 14 of the master station 10 receives the transmission signal from the slave station 30 _n, and supplies this transmission signal to the start bit detecting section 16 and the waveform shaping section 18. The start bit detector 16 detects the start bit of the transmission signal from the receiver 14 by the basic clock from the basic clock generator 15.

The reception clock generator 17 generates a reception clock having a cycle corresponding to 1 bit of the transmission signal based on the start bit supplied from the start bit detector 16 and the basic clock supplied from the basic clock generator 15. The received clock is generated and supplied to the waveform shaping section 18 and the serial / parallel conversion section 19.

The waveform shaping section 18 shapes the waveform of the transmission signal from the receiver 14 based on the reception clock from the reception clock generation section 17 and supplies it to the serial / parallel conversion section 19.

The serial / parallel conversion unit 19 synchronizes with the reception clock from the reception clock generation unit 17, and from the transmission signal waveform-shaped by the waveform shaping unit 18, each slave station 3
The data from 0 _i is extracted and supplied to the reception data storage unit 20. As a result, the data from each slave station 30 _i is stored in the reception data storage unit 20.

As described above, in this communication system, the master station 10 has each slave station 3 stored in the transmission data storage section 11.
0 _i , one frame of communication data (frame 52
_i ) each of which is composed of a start bit 50 _i and data 51 _i, and a frame 52 for all slave stations 30 _i .
_i is collected to form a series of frames 54, and a break signal (header 5
3) is added to form a transmission signal, and this transmission signal is sent to the transmission path. Each slave station 30 _i detects the break signal 53 of the transmission signal, and the start bit 50 from the detected break signal 53. The data 51 _i for the local station is detected by counting the number of the data, and the data 51 _i from the master station 10 is received. That is, this communication system does not need address information for identifying the slave station in the transmission signal, and can improve the transmission efficiency. Further, in this communication system, since the start bit is inserted in each frame of the transmission signal, it is possible to reliably achieve the synchronization in the start-stop synchronization even if the number of slave stations increases.

By the way, when the number of slave stations increases, for example, about 64 stations, the timing of the transmission signal is deviated, and in the worst case, the data 51 _i and the next start bit 50 _{i + 1} overlap each other. The remote stations may become out of sync with each other. So, for example, as shown in FIG.
The total number of bits of the start bit 50 _i and the data 51 _i is k bits, and each frame 5 consisting of this k bits
An m-bit interval 59 is provided between the two, and in the master station 10,
The number m of bits at this interval 59 is made variable based on the number n of the slave stations 30 _i to configure the transmission signal. That is, when the parallel / serial conversion unit 12 of the master station 10 collects the frames of all the slave stations 30 _i described above to form a series of frames, an interval 59 is provided between the frames.

Specifically, the parallel / serial converter 1
For example, as shown in FIG. 6, reference numeral 2 is a parallel / serial conversion in which data to be transmitted to each slave station 30 _i is read from the transmission data storage unit 11 and a start bit is added to each of these data to form a frame. 61, an oscillator 62 for generating a transmission clock, a setting switch 63 for setting the number m of bits at intervals 59, a setting of the setting switch 63, and a control signal and a gate signal based on the transmission clock from the oscillator 62. Based on a gate signal from the output counter 64, and the output of the parallel / serial converter 61 based on the gate signal from the transmitter 1
3 and a gate 65 for outputting to 3.

Then, the parallel / serial converter 61
Starts an operation in response to a control signal supplied from the output counter 64, reads data from the transmission data storage unit 11, adds a start bit to form a k-bit frame, and uses it as a transmission clock from the oscillator 62. Communication data is output synchronously. At this time, the parallel / serial converter 61 outputs the start signal to the output counter 6
Supply to 4.

When the start signal is supplied, the output counter 64 supplies to the gate 65 a gate signal which is at a high level for a period corresponding to, for example, k bits. The gate 65 supplies the output of the parallel / serial converter 61 to the transmitter 13 while the gate signal is at the high level.

The parallel / serial converter 61 supplies an end signal to the output counter 64 when the output of the communication data of one frame is completed. When the end signal is supplied, the output counter 64 supplies a gate signal, which is at a low level for a period corresponding to, for example, m bits, to the gate 65 and then supplies the control signal described above to the parallel / serial converter 61.
Supply to.

As a result, the output of the gate 65 is at the low level during the m-bit period.

Thus, the parallel / serial conversion unit 12
Is, as shown in FIG.
The transmitter 13 is supplied with a series of frames (transmission signals) having an m-bit interval 59 between the two.

Then, the slave station 30 _i receives the transmission signal configured as described above. That is, even if there is some error in the basic clock and the timing of the transmission signal fluctuates, the interval 59 can reliably separate the data 51 _i and the next start bit 50 _{i + 1} , and the slave station 30. _i
Can reliably receive data addressed to itself by synchronizing. In the embodiment described above, the bit number m (interval 59) is set by operating the setting switch 63 in correspondence with the number n of stations of the slave station 30 _i. Detecting the number n of stations 30 _i ,
The length of the space 59 may be controlled.

The present invention is not limited to the above-described embodiment. For example, as the header, in addition to the break signal, for example, a high-level signal of two frames, a signal in which a predetermined bit of data is fixed, or a specified bit is specified. It is possible to use a signal or the like composed of the data of the value of.

[0045]

As is apparent from the above description, according to the present invention, when one master station and a plurality of slave stations are connected to a ring-shaped transmission line for communication, each master station transmits each child. Each frame of communication data to be transmitted to the station is composed of synchronization information and data, and frames for all slave stations are collected,
The communication data is composed of a series of frames with header information added to the head, and the master station transmits the communication data to a plurality of slave stations via the transmission path. Each slave station receives the communication data, detects the synchronization information of a series of frames, counts the synchronization information, and receives the communication data from the master station corresponding to the own frame. Then, the slave station, which has received the communication data from the master station, replaces its own frame with a frame addressed to the master station, and sequentially transmits the communication data to the transmission path. This eliminates the need for address information to identify the slave station,
The transmission efficiency can be improved, and since the synchronization information is added to each frame, the synchronization can be surely achieved even if the number of slave stations increases.

Further, according to the present invention, by providing an interval between each frame and varying the interval based on the number of slave stations,
Even if the number of slave stations increases, it is possible to reliably synchronize.

[Brief description of drawings]

FIG. 1 is a block diagram showing a specific configuration of a master station included in a communication system to which the present invention is applied.

FIG. 2 is a block diagram showing a specific configuration of a slave station included in the communication system.

FIG. 3 is a block diagram showing a configuration of the communication system.

FIG. 4 is a diagram showing an example of a format of a transmission signal.

FIG. 5 is a diagram showing an example of a format of a transmission signal.

FIG. 6 is a block diagram showing a specific configuration of a parallel / serial conversion unit that constitutes the master station.

FIG. 7 is a block diagram showing a configuration of a conventional communication system.

[Explanation of symbols]

10 ... Parent station 11 ... Transmission data storage unit 12 ... Parallel / serial conversion unit 13 ... Transmitter 14 ... Receiver 15 ... Basic clock generation unit 16 ... Start bit detection unit 17 ... Reception clock generation unit 18 ... Waveform shaping unit 19 ... Serial / parallel conversion unit 20 ... Reception data storage unit 30 _i ... Slave station 31 ... Receiver 32 ... Basic clock generation Unit 33 ... start bit detection unit 34 ... start bit counter 35 ... transmission clock generation unit 36 ... waveform shaping unit 37 ... serial / parallel conversion units 38, 42 ... selector 39 ... -Reception data storage unit 40 ... Transmission data storage unit 41 ... Parallel / serial conversion unit 43 ... Transmitter

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-62-146041 (JP, A) JP-A-1-291548 (JP, A) JP-A-4-233351 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H04L 12/423

Claims (3)

(57) [Claims] 1. A ring-shaped transmission of one master station and a plurality of slave stations.
In a communication method of connecting to a transmission path to perform communication, one frame of communication data to be transmitted from one master station to each slave station is composed of synchronization information and data, respectively, and collects the frames for all slave stations, A communication consisting of a series of frames with header information added to the beginning.
Signal data, and the master station transmits the communication data to a plurality of slave stations via the transmission path.
Data, each of the slave stations receives the communication data , and transmits the series of data.
Detects synchronization information of frames and counts the above synchronization information
Then, the communication data from the master station corresponding to its own frame is received.
The slave station that received the communication data from the above master station
Replace the frame with a frame addressed to the master station
A communication method that sequentially transmits communication data to a transmission path. 2. A ring-shaped transmission of one master station and a plurality of slave stations.
In a communication device that communicates by connecting to a transmission path, one frame of communication data transmitted from one master station to each slave station is composed of synchronization information and data, and the above frames for all slave stations are collected, Header at the beginning
Constructs communication data consisting of a series of frames with information added.
And the communication data is transmitted via the transmission line.
Master station transmitting means for transmitting to a certain number of slave stations and the synchronization information of the series of frames which receives the communication data.
Information is detected and the above synchronization information is counted to determine the local frame
Slave station reception that receives communication data from the master station corresponding to the
Means and the slave station that has received the data from the master station,
Replace the above with the frame addressed to the master station
To a slave station for sequentially transmitting communication data.
Communication device. 3. The master station transmitting means is provided between the frames.
A space is provided between the stations, and the space can be changed based on the number of slave stations.
The communication device according to claim 2, wherein