JPH11252143A - Data transmission system and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure security and identity of data even when reception of broadcast communication data is not sufficient by communication abnormality, etc. SOLUTION: In this data transmission method, upon the receipt of a token by a certain node 1, it is confirmed that all duplicate area right flags Fk are OFF, its own duplicate area right flag Fk is set to an on-state, data are written in a duplicate write area M of a common memory CM, and a transmission signal of data contents is sent to a transmission line 3 through broadcast communication. Upon the receipt of the token by other node, when only one of the duplicate area right flags Fk is ON, the common memory CM of its own node is updated, an updated discrimination flag Fd for its own node is set to the on-state. When the certain node receives the token and two of the duplicate area right flags Fk or more are in ON states, ON state of the duplicate area right flag Fk of its own is cleared into OFF state and the duplicate write processing of other node is processed by priority.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plurality of nodes connected to each other via a ring-shaped transmission line, and a token transmitted from one node to the transmission line is sequentially transmitted to each node via the transmission line. More particularly, the present invention relates to a token circulation type data transmission method and apparatus, and more particularly, to a token circulation type LAN broadcast used in a control system.

[0002]

2. Description of the Related Art In this type of data transmission apparatus, as described in, for example, Japanese Patent Application Laid-Open No. 8-84155, each node has a common memory for writing common information. The identity of the common memory is assured by using an overlapping area right flag for exclusive control when writing data to the area and an updated determination flag for determining the reception of the broadcast communication.

[0003]

In the above-described conventional data transmission apparatus, if data is simultaneously written from a plurality of nodes to the overlapped write area of the common memory, data identity is lost and serious trouble occurs. Will happen.

[0004] Specifically, when a certain node fails to normally receive broadcast data transmitted by writing data in an overlapping write area of the common memory by another node for some reason such as a communication error. When another node executes the data write processing to the overlap write area of the common memory, the overlap area right flag that controls the exclusive control at the time of the data write overlaps, and the identity of the data of the overlap write area of the common memory overlaps. There is a problem that may be lost.

[0005] The present invention has been made in view of the above,
An object of the present invention is to provide a data transmission method and apparatus capable of guaranteeing data security and identity even when reception of broadcast data is not perfect due to a communication error or the like.

[0006]

In order to achieve the above object, according to the present invention, a plurality of nodes are connected to each other via a ring-shaped transmission line, and a plurality of nodes are transmitted from one node to the transmission line. Is a token circulation type data transmission method in which tokens are sequentially transmitted to each node via a transmission path, and an overlapping writing area in which information can be redundantly written from all nodes. A plurality of node-dedicated write areas, each of which is written with information only by a corresponding node, and the node-dedicated write area corresponding to each node. An overlap area right flag indicating that the area is in use and an update indicating that the overlap write area of each corresponding node has been updated. A common memory having a flag writing area in which a completion determination flag is written is provided in each node, and one of the nodes writes the token to the duplicate writing area of the common memory and transmits the data to each node. Is received, it is confirmed that all the overlapping area right flags in the common memory are off, the overlapping area right flag assigned to the own node is set to the on state, and then the overlapping writing area of the common memory is set. And transmits a transmission signal having the content of the common memory in which the data is written to the transmission path by broadcast communication.
In the case where the token is received, when only one overlapping area right flag corresponding to a node other than the own node in the common memory is ON, the common memory of the own node is updated with the content written by the node, The updated determination flag assigned to the own node in the common memory is set to the ON state, and the certain node receives the token, and the overlapping area right flag in the common memory is assigned to the own node. When two or more are in the ON state including the overlapped area right flag, the overlapped area right flag assigned to the own node is released to the OFF state in order to give priority to the overlapped write processing of another node,
When the token is received, when it is confirmed that only the overlapping area right flag assigned to the own node in the common memory is in the ON state and all updated determination flags in the common memory are ON. The gist of the present invention is to reset the overlapping area right flag of the own node to the off state.

According to the first aspect of the present invention, when a certain node receives a token, it confirms that all overlapping area right flags are off, and turns on the overlapping area right flag for its own node. After the setting, the data is written to the overlapping writing area of the common memory, a transmission signal of this data content is transmitted to the transmission line by broadcasting, and when the other node receives the token, the overlapping area right flag is set to 1 When only one is on, the common memory of the own node is updated, the updated determination flag for the own node is set to an on state, and when a node receives a token, the overlapping area right flag is When two or more are in the ON state including the overlap area right flag, the overlap assigned to the own node to give priority to the overlap write processing of another node To release the pass right flag to the off state,
When it is confirmed that only the overlapping area right flag for the own node is on and all the updated determination flags are on when the token is received, the overlapping area right flag of the own node is turned off. Since the resetting is performed, the identity and security of data in the overlapping writing area can be ensured even when the overlapping area right flag is set repeatedly due to a communication error or the like.

[0008] The present invention according to claim 2 is based on claim 1.
In the invention described in the above, after the certain node releases an overlapping area right flag assigned to the own node to an off state, the node shifts to a data writing waiting state, and after a predetermined time elapses, the overlapping writing area of the common memory is again returned. When the token is received in order to write data to the node and transmit it to each node, reconfirm that all the overlapping area right flags in the common memory are off, and repeat the overlapping area right assigned to the own node. After setting the flag to the ON state, the data is written to the overlapping write area of the common memory, and the transmission signal having the content of the common memory to which the data is written is transmitted to the transmission path by broadcast. .

According to the second aspect of the present invention, after a certain node releases the overlapping area right flag assigned to the own node to the off state, the node shifts to a data writing waiting state, and after a predetermined time elapses, Since the data is written to the overlapping write area of the common memory again and the transmission processing is performed, the processing is not interrupted and the data does not lose its identity.

Further, according to the present invention, a plurality of nodes are connected to each other via a ring-shaped transmission path, and a token transmitted from one node to the transmission path is transmitted to each node via the transmission path. A token circulation type data transmission device that is sequentially transmitted, wherein each node is capable of writing information redundantly from all nodes.
Each of the plurality of node-dedicated write areas, each of which is provided corresponding to each node, and in which information is written only by the corresponding node, and each of the node-dedicated write areas corresponding to each node, A common memory having a flag writing area in which an overlapping area right flag indicating that a node uses the overlapping writing area and an updated determination flag indicating that the overlapping writing area of each corresponding node has been updated are written In order to write data in the overlapping writing area of the common memory and transmit the data to each node, if the token is received, confirm that all overlapping area right flags in the common memory are off, Set the overlapping area right flag assigned to the own node to the ON state, and then Data writing and transmitting means for writing data to an overlapping write area of the memory, transmitting a transmission signal having the content of the common memory to which the data is written to a transmission path by broadcasting, and receiving the token when the token is received. When only one overlapping area right flag corresponding to another node in the node is ON, the common memory of the own node is updated with the content written by the data writing / transmitting means of the other node, and the local memory in the common memory is updated. Updated setting means for setting an updated discrimination flag assigned to the node to an on state; and, when the token is received, an overlapped area right flag in the common memory, the overlapped area right flag assigned to the own node. In order to give priority to duplicate write processing of other nodes when two or more are in the ON state The other node priority processing means for releasing the overlapping area right flag assigned to the own node to the off state, and when the token is received, only the overlapping area right flag assigned to the own node in the common memory is in the on state. The gist of the present invention is to include usage right reset means for resetting the overlapping area right flag of the own node to an off state when it is confirmed that all the updated determination flags in the common memory are on.

According to the third aspect of the present invention, when a node receives a token, it confirms that all overlapping area right flags are off, and turns on the overlapping area right flag for its own node. After the setting, the data is written to the overlapping writing area of the common memory, a transmission signal of this data content is transmitted to the transmission line by broadcasting, and when the other node receives the token, the overlapping area right flag is set to 1 When only one is on, the common memory of the own node is updated, the updated determination flag for the own node is set to an on state, and when a node receives a token, the overlapping area right flag is When two or more are in the ON state including the overlap area right flag, the overlap assigned to the own node to give priority to the overlap write processing of another node To release the pass right flag to the off state,
When it is confirmed that only the overlapping area right flag for the own node is on and all the updated determination flags are on when the token is received, the overlapping area right flag of the own node is turned off. Since the resetting is performed, the identity and security of data in the overlapping writing area can be ensured even when the overlapping area right flag is set repeatedly due to a communication error or the like.

According to a fourth aspect of the present invention, in the third aspect of the present invention, after the other node priority processing means releases the overlapping area right flag assigned to the own node to an off state, the data writing wait state is changed. The gist of the present invention is to include a restart means for restarting the data writing and transmitting means after a lapse of a predetermined time after transition to the state.

According to the present invention, after a certain node releases the overlapping area right flag assigned to the own node to the off state, the node shifts to a data writing waiting state, and after a predetermined time elapses, Since the data write transmission processing to the duplicate write area of the common memory is performed again, the processing is not interrupted and the data identity is not lost.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a data transmission device according to one embodiment of the present invention. In the data transmission apparatus shown in FIG. 1, a plurality of nodes 1a, 1b, 1c,... Are connected to each other via a ring transmission path 3 composed of a token loop type LAN or the like. The tokens transmitted to the nodes 1 are sequentially transmitted to the nodes 1 via the transmission path 3 as shown by arrows. In the present embodiment, a case where three nodes are provided as an example will be described.
Although reference numerals a, 1b, and 1c are assigned, when describing these nodes as representatives, the subscripts a, b, and c are omitted, and the nodes are described as nodes 1. Further, in the following description, when a device related to each node is also described as a representative of the node, the description will be made only with numerals or symbols without subscripts of a, b, and c, and the node will be clearly described. When it is necessary to identify, the subscripts of a, b, and c indicating which of the nodes 1a, 1b, and 1c are added to the numbers or symbols.

Each node 1 has a common memory CM as shown in FIG. This common memory CM
Are provided corresponding to the nodes 1a, 1b, 1c, respectively, and a plurality of node-dedicated dedicated write areas MA, MB,
MC, an overlapped write area M in which information can be redundantly written from all nodes 1. Each of the dedicated write areas MA, MB, and MC corresponding to each node includes a corresponding common memory CM. Area right flags Fka, Fkb, Fkc indicating that the overlapping write area M is used, and an updated determination flag indicating that the overlapping write area M of the common memory CM of each corresponding node has been updated. Fda, Fdb, and Fdc are written.

Each node 1 is connected to each of the nodes 1 shown in FIGS. 2 (a) and 2 (b).
As shown in (1), in addition to the common memory CM having the overlap area right flag Fk and the updated determination flag Fd, a token transmitted through the transmission path 3 is detected, and the token processing means 11 for acquiring the token is provided. Right flag determining means 13 for determining whether or not the overlapping area right flag Fk is set, flag setting means 15 for setting the overlapping area right flag Fk, data writing means 17 for writing data to the common memory CM, Broadcast communication means 19 for transmitting the contents as a transmission signal to the transmission path 3 by broadcast communication; updated determination flags Fda, Fdb, Fdc set in the node-dedicated write areas MA, MB, MC of the common memory CM. From all nodes 1
, A reception completion determination means 21 for determining whether or not the broadcast has been received, a flag reset means 23 for resetting updated determination flags Fda, Fdb, Fdc, an overlap area right flag in the common memory CM due to a communication error or the like. Fk includes the overlapping area right flag Fk assigned to the own node, and 2
When at least one node is set to the ON state and duplicate writing from a plurality of nodes 1 to the duplicate writing area M is detected,
Duplicate write judging means 25 for releasing the duplication area right flag Fk assigned to the own node 1 to the off state in order to give priority to the duplicate write processing of the other node 1, and whether the broadcast data has been written to the common memory CM. Broadcast determination means 27 for determining whether In the data transmission apparatus shown in FIG. 1, for the sake of simplicity of explanation, FIG. 1A shows a configuration related to a broadcast communication process, and FIG. 1B shows a configuration related to a broadcast determination process. Although they are shown functionally divided as described above, they are actually integrally formed.

Next, the operation of the data transmission apparatus configured as described above will be described with reference to the flowchart shown in FIG. Now, when the node 1a intends to execute data writing to the overlapping writing area M of the common memory CM by the token method, the node 1a processes the token transmitted from the node 1c on the transmission path 3 by token processing. Received and acquired by means 11 (step S11
0). Then, the node 1a determines whether or not the overlapped write area M can be used by the other nodes 1b and 1b.
The right flag determining means 13 checks whether the overlapping area right flags Fkb and Fkc corresponding to c have been set (step S120). If the overlapping area right flag Fk of another node is set, the process proceeds to step S
Returning to 110, the overlapping area right flag Fk of another node
Is reset, but if none of the overlapping area right flags Fk of the other nodes are set, the flag setting means 15 of the node 1a sets the overlapping area right flag Fka, and The right to use the duplicated write area M is secured (step S130).

When the overlapping area right flag Fka is set, the data writing means 17 of the node 1a writes the data into the overlapping writing area M of the common memory CM (step S140).
The write completion signal is supplied to the broadcast communication means 19.

When the broadcast communication means 19 of the node 1a receives the write completion signal from the data writing means 17,
A transmission signal having the contents of the common memory CM is transmitted to the transmission path 3 by broadcast communication. It should be noted that the broadcast communication uses the overlapping area right flags Fka, Fkb, Fkc and the updated discrimination flag F
Node dedicated write area M including da, Fdb, Fdc
This is executed in the same transmission frame having the transmission contents of A, MB, MC and the overlapping writing area M.

When the transmission signal is transmitted from the node 1a by broadcasting, the nodes 1b and 1c receive the transmission signal from the node 1a and store the contents of the respective common memories CM in the contents of the transmission signal. Is performed (step S150). Also, node 1
When the token transmitted from a goes around the nodes 1b and 1c, the token is received by the node 1a (step S160). In the course of the round of this token,
When the nodes 1b and 1c confirm that the common memory CM has been updated each time the token is obtained, the nodes 1b and 1c set the updated determination flags Fdb and Fdc to the ON state. Then, each of the nodes 1b and 1c sends the token to the transmission line 3 to send the token to the next node.

As described above, when the token makes a round of the transmission line 3, the node 1a receives the token by the token processing means 11, and the node 1a determines whether the number of sets of the overlapping area right flag Fk is only one or not. The determination is made by the write determination unit 25 (step S170). Overlapping area right flag F
If k is only one of its own overlapping area right flag Fka, the reception completion determining means 21 of the node 1a determines whether or not each node has updated the common memory CM in the common memory CM. It is checked whether or not all updated determination flags Fda, Fdb, Fdc corresponding to all nodes are set (step S180). If all the updated determination flags Fd are not set, the flow returns to step S140, and the same processing from the data writing processing is repeated until all the updated determination flags Fd are set. If the completion determination flag Fd is set, the reception completion determination means 21 determines that the broadcast has been completed, and resets its own overlapping area right flag Fka in the common memory CM by the flag reset means 23 ( (Step S190), the process ends.

If it is determined in step S170 that the number of sets of the overlap area right flag Fk is two or more, specifically, for example, the nodes 1a and 1b simultaneously make a data write request to the overlap write area M of the common memory CM. , The token is first transmitted to the node 1a, the node 1a acquires the token, and the duplicate area right flag Fk of the node-specific dedicated write area MA of the node 1a.
Is set, the data is written to the overlapping write area M, and the data is broadcast. After that, the token is transmitted to the node 1b, and the node 1b acquires the token. If the broadcast from the node 1a cannot be received for some reason, the overlapping area right flags Fk of all the nodes are in the reset state.
Node 1b determines that data has not been written to the node 1b,
Is set, the data is written to the overlapping writing area M, and the data is broadcast. As a result, two overlapping area right flags Fk are set. When two overlapping area right flags Fk have been set due to a communication error or the like, the overlapping writing determination means 25 of the node 1a.
Resets its own overlapping area right flag Fka in order to give priority to the data writing of the other node 1b that sets the other overlapping area right flag Fk other than itself (step S200).

After resetting its own overlapping area right flag Fka, the node 1a shifts to a waiting time for writing data again (step S210), and then returns to step S210.
Return to 110. Then, after the end of the waiting time, step S
Restart from 110 token acquisition. By designating a different waiting time for each node, it is possible to prevent each node from overlapping again.

As described above, in the present embodiment, the nodes which can write data in the overlapped write area M of the common memory CM are limited by the overlap area right flag Fk, and other nodes are set until the broadcast is completely completed. It is possible to prevent the node from overwriting data in the overlapped write area M. Further, even when a plurality of overlapping area right flags Fk of the overlapping writing area M are set from a plurality of nodes due to a communication error or the like, the node which detects the overlapping area right flags Fk set in a plurality of overlapping manners determines the own overlapping area. By properly resetting the right flag Fk and allowing other nodes to perform priority processing, accurate data broadcasting using the overlapping write area M can be performed without delay or loss of data identity. Can be.

In this manner, the common memory CM can be used efficiently by the exclusive control method, and the memory can be saved. Further, it is possible to know the node currently using the duplicated write area M, which is useful for data management and maintenance. Also, the overlapping area right flag Fk
Can be confirmed that the broadcast has been performed. Therefore, even if the broadcast communication fails, the broadcast can be continued until the broadcast is completed.
The identity of the M data can be guaranteed.

Next, with reference to the flowchart shown in FIG. 4, the processing of each node and the token round processing in steps S150 and S160 in FIG. 3 will be described. As described above, when the transmission signal is transmitted by broadcast from the node 1a and the node 1b receives the token from the node 1a by the token processing unit 11 (step S310),
The node 1b checks, using the content of the transmission signal received from the node 1a, whether or not the number of sets of the overlap area right flag Fk in the common memory CM is only one by the overlap write determination means 25 (step S320). If the number of overlapping area right flags Fk is not one but a plurality, as described above, for some reason, for example, a communication error or the like, one of the nodes cannot receive the previously transmitted Is written, and as a result, it is determined that two or more overlapping area right flags Fk have been set, the broadcast reception is stopped, and the updated determination flag Fd is reset (step S350). .

On the other hand, if it is determined in step S320 that the number of sets of the overlap area right flag Fk is only one, the node 1b receives the broadcast and
The common memory CM is updated with the content of the transmission signal from a (step S330), and the updated determination flag Fdb is set to indicate that the broadcast has been properly received (step S340). If the reception has not been properly performed, the updated determination flag Fdb is reset (step S
350).

[0029]

As described above, claims 1 and 3
According to the invention described above, when two or more overlapping area right flags are in the ON state when the node receives the token, the overlapping assigned to the own node to give priority to the overlapping writing processing of another node Since the area right flag is released to the OFF state, the identity and security of data in the overlapping write area can be ensured even if the overlapping area right flag is set repeatedly for some reason such as a communication error. .

According to the second and fourth aspects of the present invention, when a plurality of overlapping area right flags are set, after the node releases the overlapping area right flag assigned to the own node to the off state, The state shifts to a data write wait state, and after a predetermined time has elapsed, data is written to the duplicate write area of the common memory again and transmission processing is performed, so that processing is not interrupted and data identity is not lost.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a data transmission device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of each node of the data transmission device shown in FIG.

FIG. 3 is a flowchart showing an operation of the data transmission device shown in FIGS. 1 and 2;

FIG. 4 is a step S15 in the flowchart of FIG. 3;
It is a flowchart which shows the detailed operation of 0, S160.

[Explanation of symbols]

 1a, 1b, 1c Node 3 Transmission path 11 Token processing means 13 Right flag determination means 15 Flag setting means 17 Data writing means 19 Broadcast communication means 21 Reception completion determination means 23 Flag reset means 25 Duplicate write determination means 27 Broadcast determination means CM Common memory MA, MB, MC Dedicated write area for node M Duplicate write area Fka, Fkb, Fkc Duplicate area right flag Fda, Fdb, Fdc Updated discrimination flag

Claims (4)

[Claims] 1. A token loop type data in which a plurality of nodes are connected to each other via a ring transmission path, and a token transmitted from one node to the transmission path is sequentially transmitted to each node via the transmission path. A transmission method, comprising: a redundant write area in which information can be redundantly written from all nodes; a dedicated write corresponding to a plurality of nodes, each of which is provided corresponding to each node and each of which writes information only by a corresponding node; Area, and an overlap area right flag provided in each of the node-dedicated write areas corresponding to each node, and indicating that each corresponding node uses the overlap write area, and the overlap write of each corresponding node. A common menu having a flag writing area into which an updated determination flag indicating that the area has been updated is written. When each of the nodes receives the token in order to write data to the overlapping write area of the common memory and transmit the data to each node, all of the nodes in the common memory Confirm that the overlapping area right flag is off, set the overlapping area right flag assigned to the own node to the ON state, and then write data to the overlapping writing area of the common memory, and write the common A transmission signal having the contents of the memory is transmitted to the transmission path by broadcasting, and when receiving the token, the other nodes of the respective nodes, when receiving the token, have an overlapping area right corresponding to a node other than the own node in the common memory. When only one flag is on, the common memory of the own node is updated with the contents written by the node, and the common memory is updated. Setting the updated discrimination flag assigned to the own node in the memory to the ON state, and the certain node, when receiving the token, assigns the overlap area right flag in the common memory to the own node. When two or more are in the ON state including the area right flag, the overlapping area right flag assigned to the own node is released to the OFF state in order to give priority to the overlapping write processing of another node, and the token is received. In the above, when it is confirmed that only the overlapping area right flag assigned to the own node in the common memory is on and all the updated determination flags in the common memory are on, the overlapping area of the own node is A data transmission method comprising resetting a right flag to an off state. 2. The certain node releases the overlapping area right flag assigned to the own node to an off state, shifts to a data writing waiting state, and after a predetermined time elapses, repeats the overlapping writing area of the common memory. When the token is received in order to write data to the node and transmit it to each node, reconfirm that all the overlapping area right flags in the common memory are off, and repeat the overlapping area right assigned to the own node. After the flag is set to the ON state, data is written to the overlapping write area of the common memory, and a transmission signal having the content of the common memory to which the data is written is transmitted to the transmission line by broadcasting. The data transmission method according to claim 1. 3. A token cyclic type data in which a plurality of nodes are connected to each other via a ring-shaped transmission path, and a token transmitted from one node to the transmission path is sequentially transmitted to each node via the transmission path. A transmission device, wherein each node is provided with an overlapping write area in which information can be redundantly written from all nodes, and a plurality of nodes each of which is provided corresponding to each node and in which information is written only by the corresponding node. A node-dedicated write area, and an overlap area right flag provided in each of the node-dedicated write areas corresponding to each node, indicating that each corresponding node uses the overlap write area, and a corresponding node. A flag writing area in which an updated determination flag indicating that the overlapping writing area has been updated is written. When the token is received in order to write data in the overlapping writing area of the common memory and transmit the data to each node, it is determined that all the overlapping area right flags in the common memory are OFF. Check, set the overlapping area right flag assigned to the own node to the ON state, and then
Write data to the overlapping write area of the common memory,
A data writing / transmitting unit for transmitting a transmission signal having the content of the common memory in which the data is written to a transmission line by broadcast, and an overlap area corresponding to another node in the common memory when the token is received. When only one right flag is on, the common memory of the own node is updated with the contents written by the data writing / transmitting means of the other node, and the updated determination flag assigned to the own node in the common memory is updated. Updated setting means for setting an ON state, and when receiving the token, when two or more overlapping area right flags in the common memory are in an ON state including an overlapping area right flag assigned to the own node. The overlapping area right flag assigned to the own node in order to give priority to the overlapping write processing of another node. Other node priority processing means for releasing to the off state, and when the token is received, only the overlapping area right flag assigned to the own node in the common memory is in the on state, and all the updates in the common memory are updated. And a use right resetting means for resetting the overlapping area right flag of the own node to an off state when it is confirmed that the completion determination flag is on. 4. The another node priority processing means resets an overlapping area right flag assigned to the own node to an off state, shifts to a data writing waiting state, and after a predetermined time elapses, the data writing transmitting means. 4. The data transmission device according to claim 3, further comprising a restart unit that restarts the data transmission.