JP2001103080A - Data transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the transmitting efficiency, when the same information are transmitted to plural transmitting devices and also to effectively process an answer frame that is received from every transmitting device. SOLUTION: When a transmission frame includes plural individual control header parts C'1-C'n and individual information parts I1-In and also a single piece of information Ij includes plural destinations, sub-addresses ADR showing these destinations are included in an individual control header part C'j. Then transmitting information to be given to all transmitting devices are collected in a single frame and transmitted. Thus, the transmitting efficiency is improved. Since the answer frames are obtained in a process, where all transmitting devices receive the same frames and check them via a frame check sequence FCS, it is sufficient to merely check the answer frame that is received from one transmitting device. Thereby the answer frame processing efficiency is also improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission apparatus, and more particularly to a 1: N data transmission system for transmitting a frame between a master transmission apparatus and a plurality of slave transmission apparatuses. The present invention relates to a data transmission device that improves transmission efficiency when transmitting the same information and reduces the response confirmation processing load from a plurality of slave transmission devices in the master transmission device at that time.

[0002]

2. Description of the Related Art As a conventional frame transmission method in a 1: N type network, an HDLC procedure (High Level Data
Link Control Procedure) is well known. As described in the document "JIS Handbook-Information Processing-Security Technology, Data Communication, Document Communication Edition (1997)", in the HDLC procedure, it is necessary to generate a transmission frame for each destination, and the number of words to multiple destinations at the same time When transmitting information with a small number of frames, the ratio of overhead information for frame transmission such as F (flag sequence) or FCS (frame check sequence) to real information becomes large, so that the frame transmission efficiency decreases. There was a disadvantage. Also, a method of improving the frame transmission efficiency by removing only the flag from the overhead information may be considered (refer to the document "1816 Slotted Ring-type high-speed LA in the 1985 IEICE General Conference").
According to this method, the FCS is added to information addressed to each slave transmission device as in the conventional method, so that the degree of improvement in frame transmission efficiency is small. Further, in the above-described method, when information for a plurality of slave transmission devices is collectively transmitted, an error of information for each destination is detected by each slave transmission device by the FCS added to each destination, and as a result, Is returned as a response frame from each slave transmission device to the master transmission device. Therefore, the master transmission device receives and confirms the response frames from all the slave transmission devices of the transmission destination, and there is a problem that the response confirmation processing load on the master transmission device is high.

In the "communication control device" described in Japanese Patent Application Laid-Open No. 11-17712, the response order from each slave transmission device to a batch transmission frame is transmitted from the master transmission device to each slave transmission device in advance, and each slave transmission device A transmission system that returns a response to a master transmission device in accordance with this order when the transmission device receives a batch transmission frame is disclosed. By doing so, the idle time of each slave station when returning a response can be reduced, and the transmission efficiency of the transmission path is improved, but the response confirmation processing load on the master transmission device is still not reduced.

[0004]

As described above, in the conventional frame transmission method, when the same information is transmitted to a plurality of slave transmission devices at the same time, there is a problem that the transmission efficiency is low. There is a problem that it takes time for the response confirmation processing of the transmission device.

SUMMARY OF THE INVENTION An object of the present invention is to reduce overhead information for frame transmission when simultaneously transmitting the same information to a plurality of slave transmission devices, improve transmission efficiency, and to improve transmission efficiency of a plurality of slave transmission devices in a master transmission device. It is an object of the present invention to provide a data transmission system in which the load of processing for confirming a response from a server is reduced.

[0006]

According to the present invention, there is provided a master transmission apparatus accommodating a plurality of master control devices for managing and controlling a system, and a plurality of slave control devices operating by receiving control information from each master control device. In a data transmission system including a plurality of slave transmission devices to be accommodated, and a transmission line that connects the plurality of slave transmission devices and the master transmission device on a loop and performs HDLC frame transmission, the master transmission device includes a master control device. A first group number is defined for one or a plurality of slave control devices to which the transmission information is transmitted for each transmission information from the device and the group number is associated with the real address of the corresponding slave control device. Table, the sub-address defined for each group number and the corresponding group number And a group number corresponding to the second table obtained by inputting a plurality of pieces of transmission information from the master control device by referring to the first table using a real address of a destination slave control device of the transmission information as a key. First means for extracting non-overlapping items, second means for extracting a sub-address corresponding to each group number taken out by this means from the second table, and each sub-address taken out by this means Third means for generating a control section and an information section of an HDLC frame by concatenating a set of the transmission information and the corresponding transmission information, a control section and an information section generated by this means, and a destination address section set to broadcast. And a fourth means for generating and transmitting a transmission frame having the following formula: And 2 of the table,
When the transmission frame generated and transmitted by the fourth means is received, the destination sub-address in the transmission frame is sequentially taken out and the corresponding one is obtained by referring to the second and first staples using the destination sub-address as a key. Or fifth means for sequentially taking out a plurality of real addresses, and when the real address taken out by this means includes the real address of the slave control device accommodated in the own slave transmission apparatus, the corresponding transmission information is stored in the reception memory. And a sixth means for storing as a data transmission system.

Further, the present invention provides a master transmission device accommodating a plurality of master control devices for managing and controlling a system, and a plurality of slaves accommodating a plurality of slave control devices operating by receiving control information from each master control device. In a data transmission system including a transmission device and a transmission line that connects the plurality of slave transmission devices and the master transmission device on a loop and performs HDLC frame transmission, the master transmission device transmits a plurality of transmission signals from a master control device. First means for generating, when information is input, a set of an individual control information section in which actual addresses of one or a plurality of slave control devices as destinations are collected for each piece of transmission information and corresponding transmission information; A set of information generated by this means is connected to form a control unit and an information unit of an HDLC frame,
And second means for generating and transmitting one transmission frame whose broadcast destination address portion is broadcast,
Upon receiving the transmission frame generated and transmitted by the second means, the slave transmission device sequentially extracts the real address of the individual control information section, and the real address includes the real address of the slave control device accommodated in the slave transmission device. A third aspect of the present invention discloses a data transmission system comprising a third means for storing corresponding transmission information as reception information in a reception memory.

Further, according to the present invention, in the above-mentioned data transmission system, the master transmission device is the most downstream one of the slave transmission devices accommodating the slave control device which is the destination of the transmission frame to be generated and transmitted. Seventh means for detecting and storing the transmission device, and only when the response frame from the slave transmission device is received is the most downstream transmission device detected and stored by the seventh means, And a eighth means for receiving a response frame.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration example of a transmission system according to the present invention, which comprises a master transmission device 1 and a plurality of slave transmission devices 2 to n.
It is a transmission system. The master transmission device 1 connects the plurality of master control devices 11 to 1m1 to the interface unit 121.
And the slave transmission devices j (j = 2 to n) accommodate slave control devices j1 to jmj. The master transmission device 1 is provided with a management unit 11A including a CPU, a memory 14A as an information buffer, an information management unit 16A for generation of a transmission frame, processing of a reception frame, and the like. A transmission control unit 171, a signal transmission / reception unit 181 is connected to the loop transmission path 101. The slave transmission devices 2 to n are also connected to the transmission line 101 via a transmission control unit and a transmission / reception unit, and have the same internal configuration as the master transmission device 1, but are not shown. However, the information link management unit 16B, the most downstream transmission device determination units 16C and 16J, the destination address conversion unit 16D, and the like are not provided in the slave transmission device.

Next, a transmission frame used in the system shown in FIG. 1 will be described. FIG. 2 shows an example of a transmission frame format in the HDLC procedure. Assuming that the slave transmission devices are ST1 to STn, a frame addressed to the slave transmission device STj has a flag sequence F, a destination address portion DAj, a self-address portion SAj, It comprises a control section Cj, an information section Ij, and a frame check sequence FCSj (j = 1, 2,... N). Conventionally, information addressed to a plurality of slave transmission devices is obtained by concatenating these n frames.
Overhead information per frame is F, DA
n, SAn, Cn, and FCSn. Therefore, the overhead for n transmission devices is 7 × n
(Bytes).

FIG. 3 shows an example of a transmission frame format used in the data transmission method of the present invention, and the frame format conforms to the HDLC procedure. The information addressed to the plurality of slave transmission devices is combined into one frame, and a flag sequence F, a destination address portion DA for setting a broadcast address, an own address portion SA for setting an address of the master transmission device, and a frame type portion C
At the head, and a frame check sequence FCS and a flag sequence F indicating the end at the tail. In the meantime, the individual control header sections C'1 to C'n, the individual information section I
1 to In. Here, the individual control header sections C'1 to C'1
C'n is a header for setting management information of the individual information section, and a destination sub-address section ADR indicating a destination of the individual information section.
And individual information section size section LEN indicating the size of the individual information section
The individual information sections I1 to In are information to be transmitted to the destination indicated by the destination subaddress section ADR. Here, the destination subaddress is determined for each device of the slave transmission device, but when there are a plurality of devices of the slave transmission device receiving the same information, they are grouped into one group and one destination subaddress is given. For example, assuming that information of a plurality of destinations to be transmitted simultaneously is an individual information unit I1,
The individual control header section C′1 corresponding to the individual information section I1 includes:
As will be described later, one preset destination subaddress is given, and a plurality of slave transmission devices and devices are designated by this address.

According to such a transmission frame format of the present invention, since one frame is used for all the slave transmission devices, overhead such as a header is greatly reduced, and when transmitting the same information to a plurality of destinations, one frame is used. The transmission efficiency is greatly improved. The individual information section size section LEN becomes unnecessary when the individual information section has a fixed length.

Returning to FIG. 1, the information management unit 16A is composed of a transmission system and a reception system. First, in the transmission system, the master control devices 11 to 1
The address on the transmission buffer 16E for transferring the transmission information 14B of a plurality of destinations received from m1 is calculated by the information link management unit 15B of the information management unit 16A. Further, the information link management unit 16B manages information duplication addressed to control devices sharing the same information. The destination subaddress converted by the destination address conversion unit 16D is stored in the information link management unit 16B.
Is transferred to the address on the transmission buffer 16E calculated by the above. In the master transmission device, the information of the slave transmission device located most downstream from the master transmission device among the plurality of destinations is recorded as management information 14D for each transmission frame by the most downstream transmission device determination unit 16C. This is used to process the response from the slave transmission device.

The transmission information on the transmission buffer 16E is framed by a transmission control unit 171 and transmitted by a signal transmission / reception unit 18
1 and is transmitted to the transmission path 101. In the master transmission device 1 and each of the slave transmission devices 2 to n, the frame received from the transmission line 101 is demodulated by the signal transmission / reception unit, and received by the reception system via the transmission control unit. If the received information is described as a master transmission device, the received information is transferred to the reception buffer 16I of the information management unit 16A. The information separation management unit 16H acquires the destination sub-address part from the information of the plurality of destinations transferred to the reception buffer 16I, and the destination address conversion unit 16G changes the destination of the destination sub-address part to the destination of the control device accommodated in the transmission device. Convert to Then, the converted destination is determined by the self-address information detection unit 16F, and in the case of the self-address, the converted destination of the control device and the individual information are transferred to the reception information 14C on the memory 14A. In the master transmission device, the most downstream transmission device determination unit 16J acquires the own address portion SA on the reception buffer 16I, refers to the most downstream transmission device information (management information 14D) acquired by the transmission system, and acquires the acquired own address. It is determined whether or not the frame is from the most downstream transmission device as compared with the frame. If it is not the most downstream transmission device, the received data on the reception buffer 16I is discarded. If it is the most downstream transmission device, the received data on the reception buffer 16I is transferred to the reception information 14C on the memory 14A. DM
Data processing is performed by AC11C. Reception information 14C
Is transmitted to the corresponding control device via the interface unit 121.

The details of the entire operation will be described below. FIG. 4 is a processing flow of the transmission system, and FIG. 5 is a diagram showing details of the management information 14D on the memory. Management information 14
In D, a loop configuration information table 141, a control device grouping information table 142, and a destination address conversion information table 143 are created. The loop configuration information table 141 indicates that the master transmission device 1 is No. 1 and a rank “1” is given, and the ranks “2”, “3”,...
"H", "i", "j", etc. The control device grouping information table 142 is a table in which a group number is given to each pair of the transmission device and the device accommodated therein. This means that the same information is always sent to devices having the same group number. In FIG. 5, the same information is always sent to the control device a of the transmission device h and the control device b of the transmission device i. Number is the same Gp
And another information is sent to the control device c of the transmission device j, so that another group number Gq is given. The contents of this table 142 are determined by the configuration of the transmission device and the device. The destination address conversion information table 143 defines a destination sub-address for each of the group numbers given in the grouping information table 142.
In FIG. 5, destination subaddresses ADRp and ADRq are defined for each of the group numbers Gp and Gq. This destination subaddress is incorporated in the transmission frame and transmitted.

The transmission processing flow of FIG. 4 is started for each transmission request, and first generates the head of the transmission frame shown in FIG. 3 (step 401). Here, the destination address DA is a global address, and the own address SA is the address of the master transmission device 1. This head generation is performed by the information link management unit 16B and is written to the transmission buffer 16E. Next, the destination address of each information is obtained from the transmission information 14B on the memory 14A (Step 402). The destination address is the transmission device number and control device
Next, the most downstream transmission device determination unit 16C determines, with reference to the table 141, the slave transmission device located at the most downstream position from the master transmission device among the transmission devices at the destinations. It is recorded as a table 144 (step 403). In FIG. 5, the destination transmission device is number h, i, j of the loop configuration information table 141.
Since the transmission device j is located at the most downstream, the numbers are recorded in the most downstream transmission device management table 144 as the most downstream.

Next, one unprocessed destination address obtained in step 402 is taken out (step 40).
4) The destination address conversion unit 16D converts the extracted destination address into a destination sub-address (step 40).
5). In this conversion, for example, when the destination address is the control device a of the transmission device h, the group number Gp is acquired by referring to the control device grouping information table 142 shown in FIG. This is performed by referring to and obtaining the destination subaddress ADRP for the group Gp. Next, it is checked whether the destination subaddress obtained in this way has already been transferred to the individual control header section on the transmission buffer 16E (step 40).
6) If there is, the process proceeds to step 414, but if not, the information link management unit 16B obtains an address on the transmission buffer 16E connecting the obtained destination sub-address (step 4).
07) Transfer to the address on the transmission buffer 16E (step 408). Next, when the individual information section is set to have an arbitrary length therein, the information link management section 16B checks the size of the transmission information corresponding to the destination subaddress just transferred (step 409), and sets the size. The address of the individual information size portion LEN to be obtained on the buffer 16E is obtained (step 410), and the obtained size is transferred to the address (step 411). Further, an address on the buffer 16E for setting the transmission information is obtained (step 412), and the transmission information is taken out from the memory 14E and transferred to the address (step 413). If the individual information section has a fixed size, steps 409 to 411 are unnecessary. By the processing in steps 405 to 413 described above, the individual control header portion including the destination subaddress corresponding to one destination address and the corresponding transmission information are stored in the transmission buffer 16.
E, but only one destination and transmission information having the same group number are transferred to the transmission buffer by the processing of step 406. Next, it is checked whether there is an unprocessed destination address obtained in step 402 (step 413). If not, the process is terminated.

FIG. 6 shows an example of a transmission frame generated by the above-described transmission processing. The transmission information is, as shown in the example of FIG. The information Ip to be transmitted to the control device b of the device i (the group No. corresponds to Gp) and the information Iq to be transmitted to the control device c of the transmission device j (the group No. corresponds to Gq). The transmission frame generated at this time has a flag F
, Followed by two types of transmission information Ip, Iq and individual control headers C′p, C′q,
Then, by using the FCS and F of the tail part as one frame instead of the three frames in the conventional case, the overhead of the head and the tail part is reduced, and the same information is transmitted once. Can be transmitted to a plurality of destinations, and efficient transmission can be performed in a short time.

FIG. 7 is a flowchart of a receiving process performed in the receiving system of the slave transmission device. The reception information obtained by removing the flag sequence F from the frame received from the transmission path is stored in the reception buffer 16I by the transmission control unit. As a result, the process of FIG. 7 is started, and the information separation management unit 16H first obtains the data length L excluding the head and tail on the transmission frame from the data length of the received information (step 701).
This is the total data length of the individual control header section and the individual information section described in FIG. Next, it is checked whether L = 0 (step 702), and if L = 0, the processing is terminated. When L ≠ 0, the information separation management unit 16H obtains the destination subaddress ADR from the first individual control header unit (this is a fixed length) (step 703), and then converts this to the control device destination address by the destination address conversion unit 16G. Conversion is performed (step 704). In this conversion, the destination address conversion information table 143 and the control device grouping information table 142 described with reference to FIG. First, the transmission device and the control device address corresponding to the group number are taken out from the table 142. Then, whether the converted control device destination address belongs to the own transmission device is determined by the own address information detecting unit 16F.
(Step 705), and if it is addressed to the control device accommodated in the own transmission apparatus, the individual information size part LEN following the destination subaddress acquired in Step 703 is acquired (Step 706), and the information on the length is transmitted to the control device. The address and the address are transferred to the memory 14A (step 707). Then, a value obtained by subtracting the size of the individual control header portion processed in steps 703 to 707 and the size of the transmitted individual information portion from L is set to L (step 708), and the process returns to step 702. If it is determined in step 705 that the accommodation control device of the own transmission apparatus is not the destination, only the processing steps 709 and 710 for reducing the data size L are performed, and the process returns to step 702. When the control information has a fixed length, the size of the individual information section is obtained (706, 709).
Is unnecessary.

By the above-described slave transmission device reception processing of FIG. 7, only information destined for the own transmission device among information transmitted from the master transmission device to a plurality of slave transmission devices using the transmission frame of FIG. The information is sequentially taken out, stored as reception information on the memory 14A, and can be sent to each slave control device via the interface unit 121.
The transmission frame of FIG. 3 can greatly reduce the amount of transmission as compared with the case of transmitting one frame at a time for each conventional slave transmission device, thereby enabling efficient transmission.

In the above-described system, the control devices to be controlled by receiving the same information from the master transmission device are predetermined, and the control device grouping information table 142 created by grouping the control devices and the destination address It is assumed that the conversion information table 143 is provided in each transmission device in advance. However, according to this method, when the system configuration changes, the tables 142, 14
3 may need to be changed. Also, when there is one piece of information, (transmission device, control device) = (h,
a), (i, b), at other times, one piece of information is (h,
There may be a system in which the combination of grouping changes dynamically depending on the situation, such as simultaneous transmission in a) and (j, c). In this case, the grouping must be changed dynamically, and for this purpose, the tables 142, 1
If 43 is transmitted to the slave transmission device in accordance with the change, the transmission causes overhead and lowers the transmission efficiency.

A modification for easily coping with the above-mentioned system change and dynamic grouping change is that a set of a transmission apparatus and its control device is changed as described above (h , A), the destination sub-address A of the individual control header section in FIG.
DR is information in which destinations are arranged like (h, a) and (i, b). For example, the information data is sent to the destination (h
When sending to k pieces of (a, a1), (h2, a2)... (Hk, ak), the CDR and I1 of FIG.
1, a1), (h2, a2)... (Hk, ak)}, and I1 =
"Data". On the receiving side, if the individual control header section C'1 is decoded, the control device of the destination can be immediately known, so that even in this case, transmission can be performed with efficiency in the transmission frame of FIG. Moreover, at this time, neither the control device grouping information table nor the destination address conversion information table is required, so that there is no need to change the table, and even if the combination of grouping is dynamically changed, it can be dealt with as it is. However, in such a frame, since the length of the individual control header section is not constant, it is necessary to make a promise such as forming the individual control header section from the number of addresses and the addresses corresponding to the number.

Next, a method of confirming a response in the master transmission apparatus will be described with reference to the processing flow of FIG. As in the case of the slave transmission device, when a reception frame is received and stored in the reception buffer 16I via the signal transmission / reception unit 181 and the transmission control unit 171, the reception processing flow of FIG. 8 is started. Here, the information transmission from the slave transmission device is only a frame addressed to the master transmission device, and the same information does not have a plurality of destinations.
It is a normal transmission frame based on the LDC procedure. However, as the frame, in addition to the response frame indicating the response confirmation result described here, a frame in which the frame transmitted by itself returns after making a round of the transmission path, a frame transmitting information indicating the device state of the slave side, and the like. It is assumed that such a frame type is shown in the control units C1, C2,... In FIG. In the process of FIG. 8, first, it is determined whether there is a response frame by checking the frame type (step 801). If the received frame is not a response frame, the reception processing corresponding to the frame is performed and the processing is terminated (step 802). If the received frame is a response frame, the most downstream transmission device determination unit
Referring to FIG. 4, it is determined whether or not the frame is from the most downstream slave transmission device (step 803). If it is determined that the frame is from the most downstream transmission device, the reception data in the reception buffer 16I is transferred to the reception information 14C in the memory 14A (step 804).
Check with A to confirm the response. If the frame is not from the most downstream transmission device, the received data in the reception buffer 16I is discarded (step 805).

As described above, the transmission frame from the master transmission device in the conventional transmission system generates a frame including the destination address DA and the frame check sequence FCS for each slave transmission device, and transmits this frame. . For this reason, the error check in each slave transmission device is performed for the frame addressed to the own device using the frame check sequence FCS, and the frame check addressed to the other device cannot be performed. Therefore, the master transmission device determines whether or not retransmission is necessary by receiving all the response frames from each slave transmission device one by one, and the processing amount is correspondingly large. On the other hand, the transmission frame used in the system of the present invention shown in FIG. 3 combines information destined for all slave transmission devices into one frame.
Since the check is performed with one frame check sequence FCS, all the slave transmission devices check the contents of the same frame. Therefore, as shown in FIG. 8, the master transmission device can determine the responses of all the slave transmission devices only by looking at the response frame from the most downstream transmission device, and can perform processing such as retransmission when there is an error. Therefore, the system of the present invention has an advantage that the response confirmation processing in the master transmission device can be performed with a small processing amount.

In the conventional system, if an error occurs in the response frame for some reason despite the normal reception of information from the master transmission device, the master transmission device responds to the response from the slave transmission device. , The same frame is retransmitted again. on the other hand,
In the system of the present invention, even if such an error occurs in a response frame of a slave transmission device other than the most downstream transmission device, it is not received and processed by the master transmission device, so that unnecessary retransmission is not performed.

[0026]

According to the present invention, frame transmission between a master transmission device and a plurality of slave transmission devices is performed at 1: N
In the transmission system, it is possible to realize highly efficient transmission when transmitting the same information to a plurality of slave transmission devices at the same time, and to reduce the response confirmation processing load from the plurality of slave transmission devices in the master transmission device.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a data transmission system according to the present invention.

FIG. 2 is an explanatory diagram of a conventional HDLC frame format.

FIG. 3 is an explanatory diagram of a transmission frame used in the system of the present invention.

FIG. 4 is a transmission processing flow of a master transmission device.

FIG. 5 is an explanatory diagram of management information.

FIG. 6 is an example of a transmission frame in the system of the present invention.

FIG. 7 is a reception processing flow of the slave transmission device.

FIG. 8 is a reception processing flow of the master transmission device.

[Explanation of symbols]

 Reference Signs List 1 master transmission device 2 to n slave transmission device 11 to 1m1 control device 21 to 2m2 control device n1 to nmn control device 101 transmission line 11A management unit 14A memory 14B transmission information 14C reception information 14D management information 16A information management unit 16B information connection management Unit 16C Downstream transmission device determination unit (transmission system) 16D Destination address conversion unit (transmission system) 16E Transmission buffer 16F Self-addressed information detection unit 16G Destination address conversion unit (reception system) 16H Information separation management unit 16I reception buffer 16J most downstream Transmission device determination unit (reception system) 171 Transmission control unit 181 Signal transmission / reception unit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mamoru Ichimura 5-2-1 Omikacho, Hitachi City, Ibaraki Prefecture Inside Hitachi Process Computer Engineering Co., Ltd. (72) Inventor Takushi Hamada 5-chome Omikamachi, Hitachi City, Ibaraki Prefecture No. 2 Inside Hitachi, Ltd. Omika Works (72) Inventor Takao Nouchi 5-2-1, Omika-cho, Hitachi, Ibaraki Prefecture Inside Omika Works, Hitachi, Ltd. (72) Inventor Isao Terakado Hitachi, Ibaraki (2-1) Inventor Yoshiaki Adachi 5-2-1 Omikacho, Hitachi City, Ibaraki Pref. Hitachi, Ltd. Omika Office (72) Inventor Masanori Sakurada 5-2-1 Omika-cho, Hitachi City, Ibaraki Pref. F-term (reference) in computer engineering Co., Ltd. 5K031 AA01 AA05 BA03 CB16 CB17 DA02 DB04

Claims (3)

[Claims] 1. A master transmission device accommodating a plurality of master control devices for managing and supervising a system, and a plurality of slave transmission devices accommodating a plurality of slave control devices operating by receiving control information from each master control device. In a data transmission system comprising a plurality of slave transmission devices and the master transmission device connected on a loop and a transmission line for performing HDLC frame transmission, the master transmission device transmits the transmission information from the master control device for each transmission information. A first table created by defining the same group number for one or a plurality of slave control devices to which transmission information is sent and associating the group number with the real address of the corresponding slave control device; A second table created by associating the sub-addresses specified in When a plurality of pieces of transmission information are input from the slave control device, the first table is referred to by using the real address of the destination slave control device of the transmission information as a key, and a non-overlapping one of the corresponding group numbers is extracted. (1) means, second means for taking out the subaddress corresponding to each group number taken out by this means from the second table, and transmission information corresponding to each subaddress taken out by this means and corresponding transmission information Third means for generating a control section and an information section of an HDLC frame by concatenating the transmission section, a transmission frame having a control section and an information section generated by this means, and a destination address section set to broadcast. And each of the slave transmission devices includes a first table, a second table, and a fourth table. When the transmission frame generated and transmitted by the means is received, the destination sub-address in the transmission frame is sequentially taken out and the second
And fifth means for sequentially taking out one or more corresponding real addresses by referring to the first table, and the real address taken out by this means makes the real address of the slave control device accommodated in the own slave transmission apparatus. And a sixth means for storing the corresponding transmission information as reception information in the reception memory when the information is included. 2. A master transmission device accommodating a plurality of master control devices for managing and controlling a system, and a plurality of slave transmission devices accommodating a plurality of slave control devices operating by receiving control information from each master control device. And a transmission path for connecting the plurality of slave transmission devices and the master transmission device on a loop and performing HDLC frame transmission, wherein the master transmission device receives a plurality of pieces of transmission information from a master control device. First means for generating a set of transmission information corresponding to each transmission information and an individual control information section in which actual addresses of one or a plurality of slave control devices as destinations are collected for each transmission information; Of the information generated by the above are combined into a control section and an information section of the HDLC frame, and the destination address section is broadcasted. A second transmission unit that generates and transmits one transmission frame as the first transmission unit, wherein the slave transmission device sequentially receives the transmission frame generated and transmitted by the second unit and sequentially changes the real address of the individual control information unit. A data transmission system provided with a third means for taking out the corresponding transmission information as reception information in a reception memory when the real address is taken out and the real address of the slave control device accommodated in the own slave transmission device is included. . 3. The data transmission system according to claim 1, wherein the master transmission device is located at the most downstream position among slave transmission devices that accommodate slave control devices that are destinations of the transmission frame to be generated and transmitted. Seventh means for detecting and storing the most downstream transmission device, and when the response frame from the slave transmission device is the most downstream transmission device detected and stored by the seventh means. And a eighth means for receiving the response frame only.